7/28/2019 Separation of Ceftibuten Stereo Isomers With 100% Aqueous Mo

1/2

Ceftibuten dihydrate is currently one of the safest antimicrobial agents availableto clinicians. As a result, it is one of the most frequently prescribed antibiotics.Ceftibuten belongs to the third generation of cephalosporin antibiotics (cephems),which are used to treat many varieties of infections caused by gram-positive andnegative bacteria. Ceftibuten has two stereo isomers, the (Z) and the (E) isomers.

Most HPLC solvents are considered hazardous to health and to the environment.Safe usage and disposal of large volumes of such solvents has always posedproblems. Availability of columns, such as Zorbax SB-Aq, that can be used underhigh aqueous conditions and still retain consistent retention, resolution, selec-tivity, and peak shape is a great step in reducing the environmental impact ofthese solvents. Attempts to separate ceftibuten isomers on C18 columns withlow percentages of organic modifiers (2%) did not give good resolution and peakshape (Figure 1). However, separation of ceftibuten isomers was achieved with100% aqueous mobile phases on Zorbax SB-Aq column (Figure 2). Ceftibutenalso exhibited very good linearity and a low limit of detection (LOD) (Figure 3).

Separation of Ceftibuten Stereo Isomerswith 100% Aqueous Mobile Phase UsingZorbax SB-AqApplication

Drug Development

Adebayo O. Onigbinde

Highlights

The Zorbax SB-Aq column has analkyl bonded phase designed toeliminate phase collapse and still

retain both hydrophilic and othercompounds, when using highlyaqueous mobile phases, including100% water.

Methods that require ion-pairingreagents for retention on other C8or C18 bonded phases can oftenbe carried out on the ZorbaxSB-Aq column without ion-pairingreagents or organic modifiers.

The Zorbax SB-Aq column sepa-rated ceftibuten stereo isomerswith good peak shape and resolu-

tion in 100% aqueous phase with-out the use of ion-pairing agentsor organic modifiers.

The Zorbax SB-Aq column candeliver unique selectivity and res-olution with very good peak shapefor polar analytes that require lowlevels of organic modifier foradequate retention.

The Zorbax SB-Aq column resolvescompounds at a concentrationcommonly encountered in phar-macokinetic studies (Ceftibuten,LOD = 1.5 ng).Figure 1. Separation of ceftibuten isomers on C-18 columns with low percentages of

organic modifiers. Concentration of ceftibuten dihydrate: 3.0 mg/mL.

Experimental Conditions

Instrument: Agilent 1100 Series HPLC; Temp: ambient; Column: Alkyl-C18,4.6 150 mm, 5 m; Mobile phase: 2% ACN, 98% 10 mM ammonium acetate,pH 5.4; Flow rate: 1 mL/min; Injection volume: 5 L; Diode array detector:254 nm; Reference: 400 nm; Bandwidth: 100 nm

min0 1 2 3 4 5 6 7 8 9

mAU

0

50

100

150

200

250

300

DAD1 A, Sig = 254,100 Ref = 400,100 (71102C\001-0201.D)

1.

0641.

151

1.2

3

0

1.

371

2.

578

5.

015

Z-CeftibutenExcipent

E-Ceftibuten

7/28/2019 Separation of Ceftibuten Stereo Isomers With 100% Aqueous Mo

2/2

Agilent shall not be liable for errors contained herein or

for incidental or consequential damages in connection

with the furnishing, performance, or use of this

material.

Information, descriptions, and specifications in this

publication are subject to change without notice.

Agilent Technologies, Inc. 2002

Printed in the USA

September 18, 2002

5988-7625EN

www.agilent.com/chem

Adebayo Onigbinde is an applications

chemist based at Agilent Technologies,Wilmington, Delaware, USA.

For More Information

For more information on our productsand services, visit our Web site atwww.agilent.com/chem.

Experimental Conditions

Instrument: Agilent 1100 Series HPLC; Temp: ambient; Column: Zorbax SB-Aq,4.6 150 mm, 5 m (part number 883975-914); Mobile phase: 100% 10 mM

ammonium acetate, pH 5.4; Flow rate: 1 mL/min; Injection volume: 5 L; Diodearray detector: 254 nm; Reference: 400 nm; Bandwidth: 100 nm

DAD1 C, Sig = 254,4 Ref = 400,100 (51402B\001-0201.D)

Excipent

Z-Ceftibuten

E-Ceftibuten

min0 2 4 6 8 10 12 14

mAU

0

20

40

60

100

80

6.3

45

8.1

10

13.4

77

N

NH

N

S

S

O

O

O

O

H2NHO

OH

HH

H

N

NH

N

S

S

O

O

OH2N

HO

HO

HHHO

250.00

200.00

150.00

100.00

50.00

0.00

0 5 10 15 20

Concentration (g/mL)

Averagearea

y = 13.86x - 0.6392

R2 = 0.9955

Ceftibuten

Figure 2 Separation of ceftibuten isomers with 100% aqueous phases on Zorbax

SB-Aq column. Concentration of ceftibuten dihydrate: 3.0 mg/mL.

Figure 3. Good linearity and a low limit of detection for ceftibuten using a Zorbax

SB-Ag column.