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Transcript of phtosomes 4
NOVEL DRUG DELIVERY SYSTEM WITH SPECIAL REFERENCE TO PHYTOSOMES FOR HERBAL
FORMULATION
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Introduction
In the past few decades, considerable attention has been focused on
the development of novel drug delivery system (NDDS) for herbal drugs. The
novel carriers should ideally fulfill two prerequisites. Firstly, it should deliver
the drug at a rate directed by the needs of the body, over the period of
treatment. Secondly, it should channel the active entity of herbal drug to the
site of action. Conventional dosage forms including prolonged-release dosage
forms are unable to meet none of these. In phyto-formulation research,
developing nano dosage forms (polymeric nanoparticles and nanocapsules,
liposomes, solid lipid nanoparticles, phytosomes and nanoemulsion etc.) have
a number of advantages for herbal drugs, including enhancement of solubility
and bioavailability, protection from toxicity, enhancement of pharmacological
activity, enhancement of stability, improving tissue macrophages distribution,
sustained delivery, protection from physical and chemical degradation etc.
Thus the nano sized novel drug delivery systems of herbal drugs have a
potential future for enhancing the activity and overcoming problems
associated with plant medicines.
Liposomes, which are biodegradable and essentially non-toxic
vehicles, can encapsulate both hydrophilic and hydrophobic materials
(Medina et al., 2004). Liposome based drug delivery systems offer the
potential to enhance the therapeutic index of anti-cancer agents, either by
increasing the drug concentration in tumor cells and/or by decreasing the
exposure in normal tissues exploiting enhanced permeability and retention
effect phenomenon and by utilizing targeting strategies (Sharma et al., 2006).
The main advantages of using liposomes include: i) the high biocompatibility,
ii) the easiness of preparation, iii) the chemical versatility that allows the
loading of hydrophilic, amphiphilic, and lipophilic compounds, and iv) the
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simple modulation of their pharmacokinetic properties by changing the
chemical composition of the bilayer components (Terreno et al., 2008).
Delivery of agents to the reticuloendothelial system (RES) is easily achieved,
since most conventional liposomes are trapped by the RES (Medina et al.,
2004). The application of novel approaches can also improve the efficacy of
herbal cosmetic formulations on the human body (Chanchal and Swarnlata,
2008). Similarly the other vesicular systems like nanoemulsion, ethosomes
and transferosomes are highly useful assemblies and find various advantages
in the delivery of herbal medicines; some of them are summarized in present
article.
The phytosome process has also been applied to many popular herbal
extracts including Ginkgo biloba, grape seed,hawthorn, milk thistle (Barzaghi
et al., 1990), green tea, and ginseng. The flavonoid and terpenoid
components of these herbal extracts lend themselves quite well for the direct
binding to phosphatidylcholine. Phytosome is produced by binding individual
components of herbal extracts to phosphatidyl choline, resulting in a dosage
form that is better absorbed and thus, produces better results than the
conventional herbal extracts. The results indicate that the absorption of silybin
from silybin phytosome is approximately seven times greater compared to the
absorption of silybin from regular milk thistle extract. Drugs can be embedded
or dissolved in nanoparticles and can also be adsorbed or coupled on the
surface (Yuan and Yi, 2003). Encapsulating drugs within NPs can improve the
solubility and pharmacokinetics of drugs, and, in some cases, enable further
clinical development of new chemical entities that have stalled because of
poor pharmacokinetic properties (Alexis et al., 2008). The major carrier
materials of nanoparticles are synthetic biodegradable high molecular polymer
and natural polymer. The former usually includes poly-α-cyanoacrylate alkyl
esters, polyvinyl alcohol, polylactic acid, and polylacticcoglycolic acid, etc. The
latter is usually divided into two classes: proteins (albumin, gelatin and
vegetable protein) and polysaccharides (cellulose, starch and its derivatives,
alginate, chitin and chitosan, etc. Xiao and Li, 2002). In this seminar, an
attempt has been made to touch upon different aspects related to the
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development of novel herbal formulations, including method of preparation,
type of active ingredient, entrapment efficiency, and applications etc.
Liposome
The liposomes are spherical particles that encapsulate a fraction of the
solvent, in which they freely diffuse (float) into their interior. They can have
one, several or multiple concentric membranes. Liposomes are constructed of
polar lipids which are characterized by having a lipophilic and hydrophilic
group on the same molecules. Upon interaction with water, polar lipids self-
assemble and form self-organized colloidal particles. Simple examples are
detergents, components form micelles, while polar lipids with bulkier
hydrophobic parts cannot associate into micelles with high curvature radii but
form bilayers which can self-close into liposomes or lipid vesicles. A cross-
section of a liposome (Fig. 1) depicts the hydrophilic heads of the amphiphile
orienting towards the water compartment while the lipophilic tails orient away
from the water towards the center of the vesicle, thus forming a bilayer.
Consequently, water soluble compounds are entrapped in the water
compartment and lipid soluble compounds aggregate in the lipid section.
Uniquely, liposomes can encapsulate both hydrophilic and lipophilic materials.
Liposomes usually formed from phospholipids, have been used to change the
pharmacokinetics profile of, not only drugs, but herbs, vitamins and enzymes.
A variety of herbal liposomal formulations has been studied which are
summarized in Table 1. Because of their unique properties liposomes are able
to enhance the performance of products by increasing ingredient solubility,
improving ingredient bioavailability, enhanced intracellular uptake and altered
pharmacokinetics and bio distribution and in vitro and in vivo stability.
Liposomes as a drug delivery system can improve the therapeutic activity and
safety of drugs, mainly by delivering them to their site of action and by
maintaining therapeutic drug levels for prolonged periods of time (Barragan-
Montero et al., 2005). Milk thistle (Silybum marianum) is one of the few herbal
drugs whose excellent pharmacological profile readily lends itself to proof of
clinical efficacy (Weiss and Fintelmann, 2000). Meanwhile, silymarin is poorly
absorbed (20–50%) from the gastrointestinal tract (Blumenthal et al., 2000)
that causes the effects of silybin, one of the main active flavonoids commonly
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found in the dried fruits of silymarin, to be greater after parenteral than oral
administration (Carini et al., 1992).
Fig.1. Cross-section of a liposome (Chanchal and Swarnlata, 2008).
Incorporation of silymarin into liposomal dosage form administered
buccaly can improve its bioavailability. In this connection to improve the
bioavailability of silymarin through its incorporation in a stable liposomal
buccal dosage form, using commercially available soybean lecithin. El-
Samaligy et al., (2006) prepared silymarin encapsulated hybrid liposomes
which shows successful preparation with efficient encapsulation of silymarin.
Mixing silymarin loaded hybrid liposomes with unloaded ones in a (1:1)
proportion was useful in prevention of aggregates which threaten liposomal
stability. M50 proved stability regarding encapsulation efficiency, turbidity
measurement and particle size analysis after 3 months of storage at 4 °C or at
ambient temperature. Refrigeration is recommended to achieve better
stability. The introduced hybrid liposomal silymarin formula for buccal
administration have the advantages of exerting a mucoadhesive effect
(Takeuchi et al., 2003) besides its deformability due to the presence of Tween
20 as edge activator allowing the medicated liposomes to squeeze through
4
buccal mucosal cells. It was also shown to be safe upon contacting the rat
buccal mucosa.
5
Table 1: Liposomal herbal formulation. (Ajazuddin & Saraf, 2010)
Formulations Active Applications of liposome Biological activity Method of % Route ofingredients formulations preparation Entrapment administration
efficiency
Quercetin liposomes Quercetin Reduced dose, enhance Antioxidant Reverse 60% Intranasal
penetration in blood brain Anticancer evaporation
barrier technique
Liposomes Silymarin Improve bioavailability Hepatoprotective Reverse 69.22± Buccal
encapsulated silymarin evaporation 0.6%
technique
Liposoma artemisia Artemisia Targeting of essential oils to Antiviral Film method and 60–74% In vitro
arborescens arborescens cells, enhance penetration sonication
essential oil into, cytoplasmatic barrier
Ampelopsin liposome Ampelopsin Increase efficiency Anticancer Film-ultrasound 62.30% In vitro
method
Paclitaxel liposome Paclitaxel High entrapment efficiency Anticancer Thin film 94% In vitro
and PH sensitive hydration method
Curcumin liposome Curcumin Long-circulating with high Anticancer Ethanol injection 88.27± In vitro
entrapment efficiency method 2.16%
6
Garlicin liposome Garlicin Increase efficiency Lungs Reverse-phase 90.77 % –
evaporation
method
Flavonoids liposomes Quercetin Binding of flavonoids with Hb Hemoglobin Solvent – In vitro
and rutin is enhanced evaporation
Usnea acid liposome with Usnea acid Incrase solubility and Antimycobacterial Hydration of a thin 99.5% In vitro
β-CD localization with prolonged- lipid film method
release profile with sonication
Wogonin liposome Wogonin Sustained release effect Anticancer Film dispersion 81.20± In vivo
method 4.20%
Colchicine Liposome Colchicine Enhance skin accumulation, Antigout Rotary 66.3±2.2% Topical
prolong drug release and evaporation
improve site specificity sonication method
Catechins liposomes Catechins Increased permeation Antioxidant and Rotary 93.0±0.1 Transdermal
through skin chemopreventive evaporation
sonication method
Breviscapine liposomes Breviscapin Sustained delivery of Cardiovascular Double 87.9±3.1% Intramuscular
breviscapine diseases emulsification
process
7
Nanoparticles
In recent year, the nanonization of herbal medicines has attracted
much attention;(Zhinan et al., 2003). Some of them are illustrated in Table 2.
Nanoparticles and nanoemulsions (Fig. 2) are colloidal systems with particles
varying in size from 10 nm to 1000 nm (Ratnam et al., 2006). Nanoparticle
systems with mean particle size well above the 100 nm standard have also
been reported in literature, including nanonized curcuminoids (Tiyaboonchai
et al. , 2007), paclitaxel ( Arica et al., 2006) and praziquantel (Mainardes et
al., 2005) which have a mean particle size of 450, 147.7, and even higher
than 200 nm, respectively. In addition, nanoparticles could also be defined as
being submicronic (b1 lm) colloidal systems (Brigger et al., 2002). The
nanospheres have a matrix type structure in which the active ingredient is
dispersed throughout (the particles), whereas the nanocapsules have a
polymeric membrane and an active ingredient core. Nanonization possesses
many advantages, such as increasing compound solubility, reducing
medicinal doses, and improving the absorbency of herbal medicines
compared with the respective crude drugs preparations.
Fig. 2. Cross-section of (a) nanoemulsion and (b) biopolymeric
nanoparticle (Chanchal and Swarnlata, 2008).
8
Table 2: Nano structured herbal formulations. (Ajazuddin & Saraf, 2010)
Formulations Active Applications of Biological activityMethod of preparation
% Entrapment Route of
ingredients nanostructured formulations efficiency administration
Triptolide TriptolideEnhance the penetration of drugs through the Anti-inflammatory
Emulsification-ultrasound – Topical (skin)
nanoparticlestratum corneum by increased hydration
Nanoparticles of Cuscuta Flavonoids Improve water solubility, Hepatoprotective andNanosuspension method 90% Oral
chinensis and lignans antioxidant effects
Triptolide-loaded Triptolide Decreasing the toxicity Anti-inflammatoryEmulsification-ultrasound – Oral
solid lipid nanoparticle
Artemisinin nanocapsules Artemisinin Sustained drug release Anticancer
Self-assembly procedure 90–93% In vitro
Radix salvia R. salvia Improve the bioavailabilityCoronary heart diseases, angina
Spray-drying technique Upto 96.68% In vitro
miltiorrhiza nanoparticles miltiorrhiza
pectoris and myocardial infarction
Taxel-loaded nanoparticles Taxel Enhance the bioavailability and Anticancer
Emulsion solvent evaporation 99.44% –
sustained drug release method
Berberine-loaded Berberine Sustained drug release Anticancer Ionic gelation method 65.40±0.70% In vitro
nanoparticles
Silibini-loaded nanoparticles Silibini
High entrapment efficiency and stability Hepatoprotective
High pressure homogenization 95.64% –
Tetrandrine-loaded Tetrandrine Sustained drug release LungSelf-emulsification and solvent 84% In vitro
nanoparticles evaporating
9
Glycyrrhizic acid-loaded Glycyrrhizic Improve the bioavailability Anti-inflammatory, Rotary-evaporated 91.76% –
nanoparticles acid antihypertensivefilmultrasonication method
Quercetin-loaded QuercetinIncrease antioxidant activity and release of the Antioxidant
Nanoprecipitation technique over 99% In vitro
nanoparticles drug 74 times higher
Breviscapine-loaded Breviscapine Prolong the half-life and decreaseCardiovascular and cerebrovascular
Spontaneous emulsification 93.1% Intra Venous
nanoparticles RES uptakesolvent diffusion technique
Zedoary turmeric oil ZedoaryIncrease the drug loading and stability of ZTO
Hepatoprotection Anticancer and High pressure 1.62 ± 0.15% –
nanocapsule turmeric oil anti-bacterialHomogenization method
Loading Capacity
Naringenin-loaded Naringenin Improved the release of NAR and HepatoprotectiveNanoprecipitation method – Oral
nanoparticles improved its solubility
Curcuminoids solid lipid CurcuminoidsProlonged-release of the curcuminoids Anticancer and antioxidant
Micro-emulsion technique 70% In vitro
nanoparticles
CPT-encapsulated CamptothecinProlonged blood circulation and high Anticancer Dialysis method N80% In vitro
nanoparticles accumulation in tumors
Ginkgo biloba nanoparticles Ginkgo biloba
Improving the cerebral blood flow and Brain function activation
High pressure homogenization – Oral
extract metabolism method
10
Phytosome
Over the past century, phytochemical and phytopharmacological
sciences established the compositions, biological activities and health
promoting benefits of numerous plant products. Most of the biologically active
constituents of plants are polar or water soluble molecules. However, water
soluble phytoconstituents (like flavonoids, tannins, terpenoids, etc.) are poorly
absorbed either due to their large molecular size which cannot absorb by
passive diffusion, or due to their poor lipid solubility; severely limiting their
ability to pass across the lipid-rich biological membranes, resulting poor
bioavailability (Manach et al., 2004). It has often been observed that the
isolation and purification of the constituents of an extract may lead to a partial
or total loss of specific bio-activity for the purified constituent — the natural
constituent synergy becomes lost. Very often the chemical complexity of the
crude or partially purified extract seems to be essential for the bioavailability
of the active constituents. Extracts when taken orally some constituents may
be destroyed in the gastric environment. As standardized extracts are
established, poor bioavailability often limits their clinical utility due to above
said reasons. It has been observed that complexation with certain other
clinically useful nutrients substantially improves the bioavailability of such
extracts and their individual constituents. The nutrients so helpful for
enhancing the absorption are the phospholipids. Phytosome is a patented
technology developed by a leading manufacturer of drugs and nutraceuticals,
to incorporate standardized plant extracts or water soluble phytoconstituents
into phospholipids(phosphatidylcholine) to produce lipid compatible molecular
complexes, called as phytosomes and so vastly improve their absorption and
bioavailability(Bombardelli et al., 1989). Phospholipids are complex molecules
that are used in all known life forms to make cell membranes. In humans and
other higher animals the phospholipids are also employed as natural digestive
aids and as carriers for both fat-miscible and water miscible nutrients. They
are miscible both in water and in lipid environments, and are well absorbed
orally. Phytosomes are more bioavailable as compared to conventional herbal
extracts owing to their enhanced capacity to cross the lipoidal biomembrane
and finally reaching the systemic circulation. Phytosome has been an
emerging trend in delivery of herbal drugs and nutraceuticals.
11
Table 3: Phytosomal herbal formulations. (Ajazuddin & Saraf, 2010)Formulations Active Applications of phytosomal formulations Biological activity Method of Dose Route of
ingredients preparation administration
Ginkgo biloba Flavonoids Flavonoids of GBP stabilize the ROS Cardio-protective, Phospholipids 100 mg Subcutaneous
phytosomes antioxidant complexation and
activity 200 mg/
kg
Ginkgoselect Flavonoids Inhibits lipid peroxidation (LPO), Hepatoprotective, Phospholipids 25 and Oral
phytosome stabilize the ROS antioxidant complexation 50 mg/
kg
Silybin Flavonoids Absorption of silybin phytosome Hepatoprotective, Silybin- 120 mg Oral
phytosome from silybin is approximately antioxidant for phospholipid
seven times greater liver and skin complexation
Ginseng Ginsenosides Increase absorption Nutraceutical, Phospholipids 150 mg Oral
phytosome immunomodulator complexation
Green tea Epigallocatechin Increase absorption Nutraceutical, Phospholipids 50– Oral
phytosome systemic complexation 100 mg
antioxidant, anti-
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cancer
Grape seed Procyanidins The blood TRAP nTotal Radical-trapping Systemic Phospholipids 50– Oral
phytosome Antioxidant Parameter) were significantly antioxidant, complexation 100 mg
elevated over the control cardio-protective
Hawthorn Flavonoids Increase therapeutic efficacy Cardio-protective Phospholipids 100 mg Oral
Phytosome and absorption and Complexation
antihypertensive
Quercetin Quercetin Exerted better therapeutic efficacy Antioxidant, Quercetin– – Oral
phytosome anticancer phospholipid
complexation
Curcumin Curcumin Increase antioxidant activity and Antioxidant, Curcumin– 360 mg/ Oral
phytosomes Increase bioavailability anticancer phospholipid kg
complexation
Naringenin Naringenin Prolonged duration of action Antioxidant Naringenin– 100 mg/ Oral
phytosomes activity phospholipid kg
complex
13
14
Emulsions
Emulsion refers to a non-homogeneous dispersion system that is
composed of two kinds of liquids unable to dissolve each other, and one of
which disperse in the other one in a form of droplets. Generally, emulsion is
composed of oil phase, water phase, surfactant and sub-surfactant. Its
appearance is translucent to transparent liquid. Emulsion can be classified
into ordinary emulsion (0.1–100 μm), micro-emulsion (10–100 nm), sub-micro-
emulsion (100–600 nm), etc. (Table 4). Among them, themicro-emulsion is
also called nanoemulsions, and the sub-micro-emulsion is also called lipid
emulsion. As a drug delivery system, emulsion distributes in vivo in the
targeted manner due to its affinity to the lymph. In addition, the drug can be
sustained release in a long time because the drug is packaged in the inner
phase and kept off direct touch with the body and tissue fluid(Lu et al., 2005).
After the oily drugs or lipophilic drugs being made into O/W or O/W/O
emulsion, the oil droplets are phagocytosised by the macrophage and get a
high concentration in the liver, spleen, and kidney in which the amount of the
dissolved drug is very large.Whilewater soluble drug is produced
intoW/OorW/O/W emulsion, it can be easily concentrated in the lymphatic
system by intramuscular or subcutaneous injection. The size of the emulsion
particle has an impact on its target distribution. Apart from its targeted
sustained release, producing the herbal drug into emulsion will also
strengthen the stability of the hydrolyzedmaterials, improve the penetrability of
drugs to the skin and mucous, and reduce the drugs' stimulus to tissues.
So far, somekinds of herbal drugs, suchas camptothecin, Brucea
javanica oil, coixenolide oil and zedoary oil have been made into emulsion.
For example, Zhou et al., (2004) studied the influence of the elemenum
emulsion on the human lung adenocarcinoma cell line A549 and protein
expression. Results showed that the elemenum emulsion has a significant
inhibition on the growth and proliferation of the A549 in vitro and it showed a
time and dose-dependent relationship. Elemenum emulsion is a type of new
anti-cancer drug with great application prospects. Furthermore, it has no
marrow inhibition and no harm to the heart and liver.
15
Table 4: Emulsion herbal formulations. (Ajazuddin & Saraf, 2010)
Formulations Active Applications of Biological activity Method of preparation Droplet Drug Route ofingredients emulsion size loading administration
formulations
Self-nanoemulsifying Zedoary Improved aqueous Hepatoprotection Drawing ternary phase 68.3± 30% Oral
Zedoary essential oil turmeric dispersibility, anticancer and Diagram 1.6 nm
oil stability and oral anti-bacterial
bioavailability.
Triptolide micro- Triptolide Enhance the Anti- High pressure b100 nm – Topical
emulsion penetration of inflammatory Homogenization method
drugs through the
stratum corneum
by increased
hydration
Docetaxel submicron Docetaxel Improve residence Anticancer High pressure 166.00 nm 90% Intravenous
emulsion time Homogenization method
Berberine Berberine Improve residence Anticancer Drawing ternary phase 56.80 nm 0.50% Oral
nanoemulsion time and diagram
absorption
Silybin nanoemulsion Silybin Sustained release Hepatoprotective Emulsification method 21.20 nm – Intramuscular
formulation
Quercetin micro- Quercetin Enhance Antioxidant High speed 10– 0.3% Topical
emulsion penetration into Homogenization method 100 nm solution
stratum corneum
and epidermis
16
Other novel vesicular herbal formulations
Transferosomes are applied in a non-occluded method to the skin,
which permeate through the stratum corneum lipid lamellar regions as a result
of the hydration or osmotic force in the skin. The carrier aggregate is
composed of at least one amphiphat (such as phosphatidylcholine), which in
aqueous solvents self-assembles into lipid bilayer that closes into a simple
lipid vesicle. By addition of at least one bilayer softening component (such as
a biocompatible surfactant or an amphiphile drug) lipid bilayer flexibility and
permeability are greatly increased. The resulting, flexibility and permeability
optimised, Transfersome vesicle can therefore adapt its shape to ambient
easily and rapidly, by adjusting local concentration of each bilayer component
to the local stress experienced by the bilayer. In its basic organization broadly
similar to a liposome), the Transfersome thus differs from such more
conventional vesicle primarily by its "softer", more deformable, and better
adjustable artificial membrane.Another beneficial consequence of strong
bilayer deformability is the increased Transfersome affinity to bind and retain
water. An ultradeformable and highly hydrophilic vesicle always seeks to
avoid dehydration; this may involve a transport process related to but not
identical with forward osmosis. For example, a Transfersome vesicle applied
on an open biological surface, such as non-occluded skin, tends to penetrate
its barrier and migrate into the water-rich deeper strata to secure its adequate
hydration. Barrier penetration involves reversible bilayer deformation, but
must not compromise unacceptably either the vesicle integrity or the barrier
properties for the underlying hydration affinity and gradient to remain in place.
Since it is too large to diffuse through the skin, the Transfersome needs to find
and enforce its own route through the organ. The Transfersome vesicles
usage in drug delivery consequently relies on the carrier’s ability to widen and
overcome the hydrophilic pores in the skin or some other (e.g. plant cuticle)
barrier. The subsequent, gradual agent release from the drug carrier allows
the drug molecules to diffuse and finally bind to their target. Drug transport to
17
an intra-cellular action site may also involve the carrier’s lipid bilayer fusion
with the cell membrane, unless the vesicle is taken-up actively by the cell in
the process called endocytosis. It can be applicable as drug carriers for a
range of small molecules, peptides, proteins and herbal ingredients.
Transferosomes can penetrate stratum corneum and supply the nutrients
locally to maintain its functions resulting maintenance of skin (Benson, 2006)
in this connection the transferosomes of Capsaicin has been prepared by
Xiao-Ying et al., (2006) which shows the better topical absorption in
comparison to pure capsaicin.
Ethosome, as a novel liposome ie. Ethosomes are the modified forms
of liposomes that are high in ethanol content. The ethosomal system is
composed of phospholipid, ethanol and water, is especially suitable as a
topical or transdermal administration carrier (Jain et al., 2007; Fang et al.,
2008). The size of ethosomes vesicles can be modulated from tens of
nanometers to microns. Ethosome has a high deformability and entrapment
efficiency and can penetrate through the skin completely and improve drug
delivery through the skin. In contrast to liposomes, ethosomes have been
shown to exhibit high encapsulation efficiency for a wide range of molecules
including lipophilic drugs, and are selective at delivering molecules to and
through the skin, the physical and chemical properties of ethosomes make the
delivery of the drug through the stratum corneum into a deeper skin layer
efficiently or even into the blood circulation (Dayan and Touitou, 2000). This
property is very important as the topical drug carrier and transdermal delivery
system. Moreover, the ethosomes carrier also can provide an efficient
intracellular delivery for both hydrophilic and lipophilic drugs (Touitou et al.,
2001), percutaneous absorption of matrine an anti-inflammatory herbal drug is
increased. It also permits the antibacterial peptide to penetrate into the
fibrocyte easily. The roles of these types of novel vasicular system over herbal
drug delivery are summarized in (Table 5).
18
Table 5: Other novel vesicular herbal formulations. (Ajazuddin & Saraf, 2010)
Formulations Active ingredients Applications Biological Droplet size Route of
activity administration
Capsaicin transferosomes Capsaicin Increase skin penetration Analgesic 150.6 nm Topical
Colchicine transferosomes Colchicine Increase skin penetration Antigout – In vitro
Vincristine transferosomes Vincristine Increase entrapment efficiency and skin Anticancer 120 nm In vitro
permeation y
Matrine ethosome Matrine Improve the percutaneous permeation Anti- 110±8 nm Topical
inflammatory
Ammonium glycyrrhizinate Ammonium Increase of the in vitro percutaneous Anti- 350 nm to Topical
ethosomes glycyrrhizinate permeation inflammatory 100 nm
19
Microspheres
Administration of medication via micro particulate systems is
advantageous because microspheres can be ingested or injected and; they
can be tailored for desired release profiles and used site-specific delivery of
drugs and in some cases can even provide organ-targeted release (Sanli et
al., 2009). So far, a series of plant active ingredients, such as rutin,
camptothecin, zedoary oil, tetrandrine, quercetine and Cynara scolymus
extract has been made into microspheres (Table 6). In addition, reports on
immune microsphere and magnetic microsphere are also common in recent
years. Immune microsphere possesses the immune competence as a result
of the antibody and antigen was coated or adsorbed on the polymer
microspheres.
20
Table 6: Microspheres encapsulated herbal formulations. (Ajazuddin & Saraf, 2010)
Formulations Active Applications of Biological activity Method of Size in Route of
ingredients formulations preparation µm administration
Rutin–alginate– Rutin Targeting into cardiocascular Cardiovascular and Complex- 165.00– In vitro
chitosan and cerebrovascular region Cerebrovascular coacervation method 195.00
microcapsules diseases
Zedoary oil Zedoary oil Sustained release and Higher Hepatoprotective Quasi-emulsion– 100– Oral
microsphere bioavailability solvent diffusion 600
method
CPT loaded Camptothecin Prolonged-release of Anticancer Oil-in-water 10 Intraperitoneally
microspheres camptothecin evaporation method and intravenously
Quercetin Quercetin Significantly decreases the Anticancer Solvent evaporation 6 In vitro
microspheres dose size
Cynara scolymus Cynara Controlled release of Nutritional Spray-drying 6–7 Oral
microspheres scolymus neutraceuticals supplement technique
extract
21
Proprietary novel drug delivery system of plant actives and extracts
Cosmetochem International AG is a Swiss-based company, specialized
in the production of high quality, customized botanical extracts and actives,
launch botanical, standardized, liposomal powders named Liposome
Herbasec® [86] a novel range of standardized botanical extracts in a
liposomal-based powder form. As the liposome carriers are very effective
penetration enhancers which serve as carriers to the skin, increasing the
bioavailability of the plant extracts. In present formulation the freeze-dried
dispersion of Liposome Herbasec ® is reformed when dispersed in water, re
encapsulating the concentrated plant extract. Phospholipids used for the
preparation of formulation are the safest, mildest substances which allow the
penetration of the plant actives into the deeper layers of the epidermis and
avoid the use of solvents.There are five extracts in the current Liposome
Herbasec® range (Table 7) which are standardized for specific
phytochemicals. White and green tea are standardized for caffeine and total
polyphenols, white hibiscus for fruit acids, guarana for caffeine and aloe vera
is aloin-free. Liposome Herbasec® can be used in a wide range of personal
care applications. Smilarly based on Phytosome® technology, a line of
products has been developed and commercialized by Indena (Table 7). The
Phytosome® formulation increases the absorption of active ingredients when
topically applied on the skin (Bombardelli et al.,1991) and improves systemic
bioavailability when administered orally (Marczylo et al., 2007). A
Phytosome® is generally more bioavailable than a simple herbal extract due
to its enhanced capacity to cross the lipid-rich biomembranes and reach
circulation (Rossi et al., 2009). To overcome the poor bioavailability of silybin,
Indena has complexed it with soy phospholipids exploiting the Phytosome®
technology. As demonstrated by comparative pharmacokinetic studies,
Silipide® represents the most absorbable oral form of silybin known. The
pharmacokinetics of Silipide® in healthy human subjects showed that
complexation with phosphatidylcholine improved the oral bioavailability of
silybin 4-6 fold compared with silymarin, presumably because of a facilitated
passage across the gastrointestinal mucosa. The good bioavailability of
Siliphos® was confirmed in a human pharmacokinetic study in prostate
22
cancer patients. The study employed high dosages, and was aimed at getting
information on toxicity and phase II dosage of the product. Siliphos® at a daily
oral dose of 13 g in 3 divided doses, was well tolerated in all patients, and this
dosage was recommended for the phase II study (Flaig et al., 2007). The
results, including the optimal tolerability obtained in these “extreme” clinical
situations, provide strong support for the use of Siliphos® also in less severe
pathologies associated with liver damage. Ginkgoselect® Phytosome® was
administered at a dosage of 360 mg/day (120 mg three times per day) to 22
subjects affected by the Raynaud's disease in a double-blind, placebo-
controlled trial. Patients were required to record the frequency and duration of
any vasospastic attack, also completing a scoring scale of the overall
perception of the severity of the episodes. Patients were reviewed after two,
four and ten weeks of treatment. This pilot study showed the efficacy of
Ginkgoselect® Phytosome® in promoting a clear and highly statistically
significant reduction in the frequency (56%) and severity of Raynaud's attacks
per day (Muir et al., 2002). Meriva® is a patented complex of curcumin, a
dietary phenolic, with soy phosphatidylcholine (Kidd, 2009). A lot of work that
has been published in the journal Cancer Chemotherapy and Pharmacology
(Marczylo et al., 2007) demonstrated Meriva®'s superior bioavailability
compared to a standardized curcumin extract in rats, while very promising
initial preclinical results in terms of improved hydrolytical stability and human
pharmacokinetics have been shown more recently. Including the advantages
of these above mentioned commercialized NDDS preparation of plant
actives/extracts a variety of other preparations is also available (Table 7)
which show the remarkable advantages over pure plant actives/extracts.
23
Table 7: Marketed novel drug delivery formulations of plant active and extracts. (Ajazuddin & Saraf, 2010)
SN Brand name Plant active/extracts Type of Company
NDDS name
1 White tea liposome Herbasec® Camellia sinensis extract Liposome Cosmetochem
2 Green tea liposome Herbasec® Camellia sinensis Extract Liposome Cosmetochem
3 White hibiscus liposome Herbasec® White hibiscus extract Liposome Cosmetochem
4 Aloe vera liposome Herbasec® Aloe vera Extract Liposome Cosmetochem
5 Guarana liposome Herbasec® Guarana extract Liposome Cosmetochem
6 18ß-glycyrrhetinic acid Phytosome® 18ß-glycyrrhetinic acid from licorice rhizome Phytosome Indena
7 Centella Phytosome® Triterpenes from Centella asiatica leaf Phytosome Indena
8 Crataegus Phytosome® Vitexin-2″-O-rhamnoside from Hawthorn flower Phytosome Indena
9 Escin ß-sitosterol Phytosome® Escin ß-sitosterol from horse chestnut fruit Phytosome Indena
10 Ginkgoselect® Phytosome® Ginkgoflavonglucosides, ginkgolides, bilobalide from Phytosome Indena
Ginkgo biloba leaf
11 Ginselect® Phytosome® Ginsenosides from Panax ginseng rhizome Phytosome Indena
12 Ginkgo biloba terpenes Phytosome® Ginkgolides and bilobalide from Ginkgo biloba leaf Phytosome Indena
13 Ginkgo biloba dimeric flavonoids Phytosome® Dimeric flavonoids from Ginkgo biloba leaf Phytosome Indena
14 Greenselect® Phytosome® Polyphenols from green tea leaf Phytosome Indena
15 Leucoselect® Phytosome® Polyphenols from grape seed Phytosome Indena
16 Meriva® Curcuminoids from turmeric rhizome Phytosome Indena
17 PA2 Phytosome® Proanthocyanidin A2 from horse chestnut bark Phytosome Indena
18 Sericoside Phytosome® Sericoside from Terminalia sericea bark root Phytosome Indena
19 Siliphos® Silybin from milk thistle seed Phytosome Indena
20 Silymarin Phytosome® Silymarin from milk thistle seed Phytosome Indena
21 Virtiva® Ginkgoflavonglucosides, ginkgolides, bilobalide from Phytosome Indena
Ginkgo biloba leaf
22 Visnadex® Visnadin from Ammi visnaga umbel Phytosome Indena
24
Phytosomes as a boon for herbal drug delivery
Herbal drugs containing bioactive constituents are mainly water soluble
molecules. However, many flavonoid which are water soluble
phytoconstituents like to be poorly absorbed (Manach et al., 2004) due to their
poor miscibility with oils and other lipids or due to their multiple-ring large size
molecules which cannot be absorbed by simple diffusion, severely limiting
factors are available for their ability to pass across the lipid-rich outer
membranes of the enterocytes of the small intestine. Polyphenols (Water-
soluble phytoconstituents) molecules can be converted into lipid-compatible
molecular complexes, which are called Phytosomes. Phytosomes are more
bioavailable in comparison to simple herbal extracts. They have enhanced
capacity to cross the lipid rich biomembranes and finally reaching the blood
(Bombardelli et al., 1989). The lipid-phase substances employed to make
phytoconstituents, lipid compatible are phospholipids from soy, mainly
phosphatidylcholine (PC). Phospholipids are complex molecules that are used
in all known life forms to make cell membranes. The term “Phyto” means plant
while “some” means cell-like. The Phytosomes process itself produces a little
cell whereby the valuable component of the herbal extract is protected from
destruction by digestive secretions and gut bacteria. Many popular
standardized herbal extracts comprising of flavanoids, polyphenolics,
terpenes, alkaloids, volatile oils are employed for the preparation
ofphytosomes. Flavonoids are the most important group of phytochemicals.
Flavonoids are the class of compounds that have referred to be a natural
biological response modifier which acts as powerful antioxidants that
providing remarkable protection against oxidative and free radical damage.
Various flavonoids which have shown antioxidant activity 50 to 200 times
more potent than vitamin C or E. we can use certain flavonoids-rich extracts
that referred as “tissue specific antioxidants” due to their ability of
concentrated in specific body tissue. There are many plant drugs that are
incorporated to Phytosomes process as herbal extracts including Ginkgo
biloba, grape seed, hawthorn, milk thistle, green tea, and ginseng
.Phytosomes are more bioavailable as compared to conventional herbal
extracts owing to their enhanced capacity to cross the lipoidal biomembrane
and finally reaching the systemic circulation. So, Phytosomes has been a
novel approach for the herbal drug delivery (Bhattacharya, 2009).
Method of preparation:
25
Phytosomes are complexes chemical mixtures which are prepared by
reacting from with one or two mole of natural or synthetic phospholipids
phosphatidyl ethanolamine or phosphatidyiserine with one mole of
component. For example, flavolignanans, either alone or in the natural mixture
in aprotic solvent such as- dioxane or acetone from which complex can be
isolated by precipitation with non solvent such as aliphatic hydrocarbons or
lyophilization or by spray drying. In the complex formation of Phytosomes the
ratio between these two moieties is in the range from 0.5-2.0 moles. The most
preferable ratio of phospholipids to flavonoids is 1:1. In the Phytosomes
preparations, phospholipids are selected from the various group such as,
phosphatidyl, ethanolamine, phosphatidylcholine, soy lecithin, from bovine or
swine brain or dermis, phosphatidyiserine in which acyl group may be same
or different and mostly derived from palmitic, stearic, oleic and linoleic acid.
Flavonoids are selected from the group consisting of quercetin, kaempferol,
quercretin-3, rhamnoglucoside, quercetin- 3- rhamnoside, hyperoside,
vitexine, diosmine, 3- rhamnoside, (+). Some liposomal drugs complex
operate in the presence of the water or buffer solution where as phytosomes
operate with the solvent having a reduced dielectric constant. Flavonoid which
is the Starting material of component is insoluble in chloroform, ethyl ether or
benzene. They become extremely soluble in these solvents after forming
phytosomes. This chemical and physical property change is due to the
formation of a true stable complex (Sharma and Sikarwar, 2005).
How Phytosomes differ from liposome ?
Likewise Phytosomes, a liposome is formed by mixing
phosphatidylcholine with water soluble substance in definite ratio. The
phosphatidylcholine molecules surround the water soluble substance in which
no chemical bond is formed. There are hundreds or even thousands of
phosphatidylcholine molecules surrounding the water-soluble compound. In
contrast, with the Phytosomes process the plant components and the
phosphatidylcholine actually form a 1:1 or a 2:1 molecular complex depending
on the substance(s) complexed, in which chemical bond is formed. This
difference shows that Phytosomes being much better absorbed than liposome
showing better bioavailability. Phytosomes have also been found superior
than liposome in topical and skin care.
26
FIG. 1: PHYTOSOMES DIFFER FROM LIPOSOMES
Properties of Phytosomes
Chemical properties: Phytosomes are novel complexes formed between the
natural product and natural phospholipids, like soy phospholipids. Such a
complex is obtained by reaction of stoichometric amounts of phospholipid and
the substrate in an appropriate solvent. On the basis of spectroscopic data it
has been shown that the interaction of phospholipid-substrate is due to the
formation of hydrogen bonds between the polar head of phospholipids (i.e.
phosphate and ammonium groups) and the polar functionalities of the
substrate.
When it treated with water, phytosomes assumes a micellar shape which
formed the liposomal-like structures, In liposome the active principle is floating
in the layer membrane, while in phytosomes the active principle is anchored
to the polar head of phospholipids, becoming an integral part of the
membrane for example in the case of the catechindistearoyl
phosphatidylcholine complex, there is the formation of H-bonds between the
phosphate ion on the phosphatidylcholine side and the phenolic hydroxyls of
the flavone moiety.
27
FIG. 2: PHOSPHATIDYLCHOLINE COMPLEX
Phosphatidylcholine: This can be assumed from the comparison of the
NMR of the complex with the precursors of complex.The signals of the fatty
chain are almost unchanged. Such evidences inferred that the two long
aliphatic chains are wrapped around the active principle, producing a lipophilic
envelope, which shields the polar head of the phospholipid and the catechin.
Biological Properties: Phytosomes are advanced botanical technology that
offers improved absorption, enhanced delivery and increased bioavailability of
herbal extracts phytosomes over the non complexed botanical derivatives has
been demonstrated by pharmacokinetics studies or by pharmacodynamic
tests in experimental animals and in human subjects.
The Phytosome Technology: The flavonoid and terpenoid constituents of
plant extracts provide them for the direct binding to phosphatidylcholine.
Phytosomes results from the reaction of a stoichometric amount of the
phospholipid (phosphatidylcholine) with the standardized extract or
polyphenolic constituents in a non polar solvent (Bombardelli et al., 1989).
Phosphatidylcholine is a bifunctional compound, the phosphatidyl moiety
being lipophilic and the choline moiety being hydrophilic in nature. In
particular, the choline head of the phosphatidylcholine molecule binds to
28
these compounds while the lipid soluble phosphatidyl portion comprising the
body and tail which then envelopes the choline bound material
Hence, the Phytoconstituents produce a lipid compatible molecular complex
with phospholipids, also called as phytophospholipid complex. By specific
spectroscopic techniques, it can be demonstrated that the molecules are
anchored through chemical bonds to the polar choline head of the
phospholipids (Bombardelli, 1991). Precise chemical analysis designate that
the unit phytosome is usually a flavonoid molecule linked with at least one
phosphatidylcholine molecule. The result is a little micro sphere or cell is
produced. The term "Phyto" means plant while "some" means cell-like. The
phytosome technology produces a little cell, whereby the plant extract or its
active constituent is protected from destruction by gastric secretions and gut
bacteria owing to the gastro protective property of phosphatidylcholine.
Characterization of Phytosomes: There are many factors which govern the
behavior of phytosomes in both physical and biological system, such as
physical size membrane permeability; percent entrapped solutes, chemical
composition as well as the quantity and purity of the starting materials.
Therefore, the phytosomes are characterized for physical attributes i.e. shape,
size, its distribution, percentage drug capture entrapped volume, percentage
drug released and chemical composition (Jain, 2005).
Enhanced bioavailability: Recent researches showed that most of the
phytosomal studies are focused to Silybum marianum (milk thistle) which
contains premier liver-protectant flavonoids. The fruit of the milk thistle plant
contains flavonoids known for hepatoprotective effects (Bombardelli et al.,
1991). Silybin is the chief and most potent constituent of silymarin, the
flavonoid complex from milk thistle. A standardized extract from Silybum
marianum (milk thistle) is an excellent liver protectant but very poorly
absorbed orally.
Yanyu et al., (2006) prepared the silymarin phytosome and show its
pharmacokinetics in rats. In the study after oral administration of prepared
Silybin phospholipid complex, the bioavailability of Silybin in rats was
29
increased remarkably due to an impressive improvement of the lipophilic
property of Silybin-phospholipid complex and the biological effect of Silybin
was improved. Tedesco et al., (2004) reported Silymarin phytosome show
better anti-hepatotoxic activity than silymarin alone. Silymarin phytosome
provide protection against the toxic effects of aflatoxin B1 on performance of
broiler chicks.
Moscarella et al., (1993) perform a human study of 232 patients with
chronic hepatitis (viral, alcohol or drug induced). They are treated with Silybin
phytosome at a dose of 120 mg either twice daily or thrice daily function
returned to normal faster in patients taking Silybin phytosome compared to a
group of commercially available silymarin, 117 controls (49 treated with for up
to 120 days, liver untreated or given placebo). Studies have shown ginkgo
phytosome (prepared from the standardized extract of Ginkgo biloba leaves)
produced better results than the conventional standardized extract from the
plant.
Grape seed phytosome is prepared from grape seed extract containing
oligomeric polyphenols (grape proanthocyanidins or procyanidinsrom) of
varying molecular size, complexed with phospholipids. The main properties of
procyanidin flavonoids of grape seed that they increase the total antioxidant
capacity and stimulation of physiological antioxidant defenses of plasma,
protective effects against atherosclerosis thereby offering marked protection
for the cardiovascular system, protection against ischemia/reperfusion
induced damages in the heart, and other organs through a network of
mechanisms that extend beyond their great antioxidant potency (Schwitters
and Masquelier, 1993).
Despite such potential actions green tea polyphenols have very poor
oral bioavailability from conventional extracts. The complexation of green tea
polyphenols with phospholipids strongly improves their poor oral
bioavailability. A study on absorption of phytosomal preparations was
performed in healthy human volunteers along with complexed green tea
extract following oral administration. Over the study period of 6 hours the
plasma concentration of total non flavonoids was more than doubled when
30
coming from the phytosomal versus the nonphytosomal extract. Antioxidant
capacity was measured as TRAP (Total Radical-trapping Antioxidant
Parameter). The peak antioxidant effect was a 20% enhancement and it
showed that the phytosome formulation had about double the total antioxidant
effect. Maiti et al., (2005) developed the quercetin phospholipid phytosomal
complex which showed that the formulation exerted better therapeutic efficacy
than the molecule in rat liver injury induced by carbon tetrachloride. Recently
they developed the phytosomes of curcumin (flavonoid from turmeric,
Curcuma longa) and naringenin (flavonoid from grape fruit, Vitis vinifera) in
two different studies (Maiti et al., 2006). The antioxidant activity of the
quercetin phospholipid phytosomal complex was significantly higher than pure
curcumin in all dose levels tested.
Advantages of Phytosomes (Kidd and Head, 2005) : Phytosomes have the
following advantages;
Phosphatidylcholine used in preparation of phytosomes, besides acting
as a carrier also acts as a hepatoprotective, hence giving the
synergistic effect when hepatoprotective substances are employed.
They enhance the absorption of lipid insoluble polar phytoconstituents
through oral as well as topical route showing better bioavailability,
hence significantly greater therapeutic benefit.
As the absorption of active constituent(s) is improved, its dose
requirement is also reduced.
Chemical bonds are formed between phosphatidylcholine molecule
and phyto constituents, so the phytosomes show better stability profile.
Added nutritional benefit of phospholipids
31
FIG. 3: ORGANIZATION OF THE PHYTOSOME MOLECULAR COMPLEX
Applications of Phytosomes: There are many plant drugs that are
incorporated to Phytosomes process as herbal extracts including Ginkgo
biloba, grape seed, hawthorn, milk thistle, green tea, and ginseng. Most of the
phytosomal studies are focused to Silybum marianum which shows that it
contains premier liver-protectant flavonoids. The fruit of the milk thistle plant
(S. marianum, Family steraceae) contains flavonoids known for
hepatoprotective effects. It was found that Silymarin has been shown to have
positive effects in treating liver diseases of various kinds, including
inflammation of the bile duct, hepatitis, cirrhosis and fatty infiltration of the
liver. The antioxidant capacity of silymarin significantly boosts the liver’s
resistance to toxic insults (Valenzuela et al., 1989). Silymarin primarily
contains three flavonoids of the flavonol subclass. Silybin predominates,
followed by silydianin and silychristin. Silybin is a flavonolignan which is
probably produced within the plant by the combination of a flavonol with a
coniferyl alcohol. It is now known that Silybin is the most potent of the three
(Hiking et al., 1984). Silybin protects the liver by conserving glutathione in the
parenchymal cells, while PC helps repair and replace cell membranes (Kidd,
1996). These constituents offer the synergistic benefit of sparing liver cells
from destruction. In its native form within the milk thistle fruit, Silybin occurs
primarily complexed with sugars, as a flavonyl glycoside or flavonolignan
Silybin has been extensively researched and found to have impressive
bioactivity, albeit limited by poor bioavailability.
TABLE 8: COMMERCIAL PHYTOSOME PREPARATIONS
Phytosomes Phytoconstituent complexed Indication
32
with Phosphatidylcholine
Silybin
Phytosome TM
Silybin from Silymarin Food Product,
antioxidant for Liver
and skin.
Ginkgo
Phytosome TM
24 % ginkgoflavonglycosides
from Ginkgo biloba
Protects brain and
vascular lining, Anti-
skin ageing agent.
Panax ginseng
Phytosome TM
37.5 % ginsenosides from roots
of Panax ginseng
Food Product.
Green Tea
Phytosome TM
Epigallocatechin 3-O- gallate
from Camelia sinensi
Food Product,
Systemic antioxidant,
Cancer protectant.
Super Milk thistle
Extract
Silybin from Silymarin Food Product;
antioxidant for liver
and skin.
Grape seed
(PCO)
Phytosomes
Procyanidolic oligomers (PCOs)
from grape Seeds
Food Product; protects
against heart
Hawthorn
Phytosomes
Flavonoids Food Product.
Centella
Phytosome
Terpenes Vein & skin disorders.
CONCLUSION:
An extensive research is going on in the area of novel drug delivery
and targeting for plant actives and extracts. Herbal drugs have enormous
33
therapeutic potential which should be explored through some value added
drug delivery systems. Lipid solubility and molecular size are the major
limiting factors for drug molecules to pass the biological membrane to be
absorbed systematically following oral or topical administration. Standardized
plant extracts or mainly polar phytoconstituents like flavonoids, terpenoids,
tannins, xanthones when administered through novel drug delivery system
show much better absorption profile which enables them to cross the
biological membrane, resulting enhanced bioavailability. Phytosomes forms a
bridge between the convectional delivery system and novel delivery system.
The Phytosome process has been applied to many popular herbal extracts
including Ginkgo biloba, grape seed, hawthorn, milk thistle, green tea, and
ginseng. The flavonoid and terpenoid components of these herbal extracts
lend themselves quite well for the direct binding to phosphatidylcholine.
Through study of literature reveals that phytosome show promise in reliving
the pain and symptoms associated with asthma, arthritis, rheumatism, ulcers,
phlebitis, edema, varicose veins, premenstrual syndrome, diabetic retinopathy
and hemorrhoids. Phytosomes are used as a medicament and have wide
scope in cosmetology. Many areas of phytosome are to be revealed in future
in the prospect of pharmaceutical application.
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