Determination of Emulsion Types

Click here to load reader

  • date post

  • Category


  • view

  • download


Embed Size (px)

Transcript of Determination of Emulsion Types


There are many methods available for the determination of emulsion type but the most commonly used are: Drop dilution method. Dye solubility method. Fluorescent test. Electrical conductivity test. Direction of creaming test. Filter paper test. These methods determine whether the emulsion is oil in water (o/w) type or water in oil (w/o) type. DROP DILUTION METHOD: This method is based on the principle that emulsion is always miscible with the external phase. If water is added to water in oil w/o type emulsion, it will not be mixed. On the other hand, oil mixes well. Same is the case with o/w type emulsion. If oil is added to oil in water o/w type emulsion, it will not be mixed. On the other hand, water mixes well. DYE SOLUBILITY METHOD: It is based on the solubility of any dye in the external phase. Amaranth, a water soluble dye gives color to oil in water o/w type emulsion, but not to water in oil w/o type emulsion. Same is the case with oil soluble dyes. FLUORESCENT TEST: Based on the fluorescence of oils under ultraviolet light, the emulsion is examined under the light in the microscope. If the whole fluid is fluorescent, it is water in oil w/o but in case of oil in water o/w spotty fluorescence will appear. ELECTRICAL CONDUCTIVITY TEST: Based on the electrical conductivity of aqueous solutions, the electric current is supplied and electrodes are placed in the emulsion. If the current is passed, it is oil in water o/w and if is not passed, it is water in oil w/o.

DIRECTION OF CREAMING TEST: Creaming is the sedimentation of the dispersed phase which is either upwards or downwards, upon which this test is based. The density of oil is mostly less than water. Thus if creaming is at the upper side, it is oil in water o/w and if it is downwards, it is water in oil w/o type of emulsion. FILTER PAPER TEST: Take a filter paper, put a drop of emulsion on the filter paper. Evaporate it; if there is a spot on the filter paper, the emulsion will be water in oil w/o. On the other hand, if there is no spot, the emulsion will be of oil in water o/w type. DETERMINATION OF TOTAL SOLIDS The term total solids is applied to the residue obtained when the prescribed amount of the preparations is dried to constant weight under the conditions specified. Total solids usually include extractives, both soluble and insoluble in alcoholic or hydro-alcoholic preparations as tinctures and extracts. The total solids are calculated as g/100ml This test is more preferably performed for the tinctures or galenical preparations containing a higher amount of solid contents. PROCEDURE: Take a china dish, weigh it then add 5ml of the tincture or the given preparations. Heat this to evaporation. Then weigh it again. Increase in weight is the weight of total solids in 5ml of sample. Specific ranges are given in pharmacopoeia. Posted by The Pharmacist at 12:33 PM 0 comments Labels: QUALITY CONTROL TESTING EVALUATION OF ELIXIRS Links to this post

Elixirs are clear sweetened usually hydro-alcoholic liquids containing flavoring substance. TESTS FOR THE EVALUATION OF ELIXIR Following are the tests for the evaluation of elixirs.

Consistency. pH determination. Refractive index Alcoholic contents. Identification. Assay of active contents. CONSISTENCY: Should be clear. pH DETERMINATION: 6.0 to 7.0. REFRACTIVE INDEX: 1.4608-1.4630. ALCOHOL CONTENTS: It should be 1 of the percentage given in the monograph.

IDENTIFICATION: To 5ml add 2ml of 5M NaOH and mix. A liquid with the odour of chloroform is separated. ASSAY OF ACTIVE CONTENTS: To 3 grams add 25 grams of Zinc powder, 15ml of glacial acetic acid. Add 30ml of water, boil under reflux condenser for 30 minutes, cool, filter through absorbent cotton, wash the residue with water and combine the filtrate. Add 20 ml of 2M Nitric acid, wash the residue with water and titrate the excess of silver nitrate with 0.1M Ammonium Thiocyanate using Ammonium iron sulphate as an indicator. Each ml of 0.1M silver Nitrate 0.005513 grams of C2H3Cl3O2.

Posted by The Pharmacist at 12:32 PM 0 comments

Links to this post


Syrups are concentrated aqueous solutions having 66.7 % w/v of sucrose. Syrups also contain aromatic or other flavoring materials. TESTS FOR EVALUATION OF SYRUPS Following tests are specified for the evaluation of syrups: Consistency. pH determination. Refractive index. Identification of active contents. Assay of active contents. Solubility. CONSISTENCY: Should be clear solution. There should be no solid particles. pH DETERMINATION: Determine the pH of syrup by suitable means; it should be 6.0 to 7.0. REFRACTIVE INDEX: The value of refractive index should be in the range of 1.4608 to 1.4630. IDENTIFICATION OF ACTIVE CONTENTS: Identify the active contents of syrup by suitable means e.g. invert syrups dissolve with 10 ml of water and 5ml of potassium cupric tartarate solution. A red precipitate is produced. ASSAY OF ACTIVE CONTENTS: For example, Lemon syrup. Mix 8 grams with 100ml of water and titrate with 0.1M NaOH using phenolphthalein as an indicator.

Each ml of 0.1M NaOH=0.007005 grams of C6H8O7.H2O SOLUBILITY: Soluble in water. Posted by The Pharmacist at 12:32 PM 0 comments Labels: QUALITY CONTROL TESTING PYROGEN TEST Links to this post

This test consists of measuring the rise in body temperature evoked in rabbits by the injection of a sterile solution of the substance being examined. PYROGENS: Pyrogens are the by-products of microorganisms mainly of bacteria, molds and viruses. During the processing these pyrogens may come from water, active constituent or the excipient or from the equipments. Chemically these pyrogens are lipid substances associated with carrier usually polysaccharides or may be proteins. Parenteral solutions are officially tested for the presence of pyrogens by a biological test in which FEVER response of rabbits is used as criteria. SELECTION OF ANIMALS: Use healthy adult rabbits of any sex weighing not less than 1.5kg. Feed them a well balanced diet not containing any antibiotics during one week preceding the test. A rabbit should not be used in the pyrogen test if: It has been used in a negative pyrogen test in the preceding three days or It has been used in the preceding three weeks in a pyrogen test in which the substance under examination fails to pass the test or It has been used at any time in the pyrogen test in which the mean response of the rabbit in the group exceeds 1.2C. MATERIALS NEEDED: (a). THERMOMETERS:

The thermometer or electrical device used should indicate the temperature with a great sensitivity and should be inserted in the rectum of the rabbit to the depth of about 5.2cm (B.P specification) or 7.2cm (USP specification). The depth of insertion is constant for any rabbit in every group. When an electrical device is used, it should be inserted in the rectum of the rabbit 90 minutes before injection of the solution to be examined and left in position throughout the test. (b). GLASSWARE, SYRINGES AND NEEDLES: All the glassware, syringes and needles must be thoroughly washed with water and heated in a hot air oven at 250C for 30 minutes or at 200C for an hour. (c). RETAINING BOXES: The retaining boxes for rabbit in which the temperature is being measured by and electrical device should be made in such a way that the animals are retained only by loosely fitting neck stocks, the rest of the body remains relatively free, so the rabbit may sit in a normal position. The animals must be put in box not less than one hour before the test and remain there throughout the test. PRELIMINARY TEST (SHAM TEST): One of the three days before testing the product, inject pyrogen free isotonic NaCl solution (10ml/kg body weight warmed at 38.5C intravenously) into animal, which has not been used during the two previous weeks. Record the temperature of animal beginning at least 90 minutes before injection and continuing for 3 hours after injection of solution. Any animal showing a temperature difference greater than 0.6C must not be used in the main test. MAIN TEST: Carry out the test using a group of three rabbits. PREPARATION AND INJECTION OF SAMPLE Warm the liquids to be examined to approximately 38.5C before injection. The sample liquid to be injected may be diluted with a pyrogen free isotonic NaCl solution. Inject the solution slowly into the marginal vein of the ear of each rabbit over a period of four minutes, unless otherwise mentioned in the monograph. The volume of the injection should be not less than 0.5ml/kg body weight and should not be more than 10ml/kg body weight. DETERMINATION OF INITIAL AND MAXIMUM TEMPERATURE

The initial temperature of each rabbit is the mean of two temperature readings, recorded for that rabbit at an interval of 30 minutes immediately preceding the injection. While the maximum temperature is the highest temperature recorded for that rabbit three hours after the injection of the preparation being tested. Record the temperature of each animal at an interval of 30 minutes beginning at least 90 minutes before the injection. The difference between the initial temperature and the maximum temperature of each rabbit is taken to be its response. When this difference is negative, the result is counted as zero response. REJECT THE RABBIT IF: It is having an initial temperature higher than 39.8C or lower than 38.0C. It is showing temperature difference more than 0.2C between two successive readings taken during the 90 minutes. INTERPRETATION OF RESULTS Having carried out the test on a group of three rabbits, repeat if necessary on further groups of three rabbits to a total of four groups. Depending on the results obtained tabulate the results in the following manner. NUMBER OF RABBITS 3 RABBITS 6 RABBITS 9 RABBITS 12 RABBITS 1.15C 2.80C 4.45C 6.10C 2.65C 4.30C 5.95C 7.60C Links t