Chiral stability of an extemporaneously prepared clopidogrel bisulfate oral suspension.
OBJECTIVE
The purpose of this study was to evaluate the chiral stability of clopidogrel bisulfate in an extemporaneously compounded oral suspension for a period of 60 days.


METHODS
A 5 mg/mL oral suspension of clopidogrel bisulfate was prepared from commercially available Plavix tablets. The clopidogrel suspension was then evenly divided between two light-resistant prescription bottles and stored either under refrigeration (4°C) or at room temperature (25°C). Samples were drawn from the stored suspensions immediately after preparation and on days 7, 14, 28, and 60. Samples were subsequently analyzed at each time point by high-performance liquid chromatography using a reversed-phase column, with chemical stability defined as the retention of at least 90% of the initial intact clopidogrel concentration measured. To determine the chiral stability of the suspension, samples were also analyzed by high-performance liquid chromatography using a chiral column to investigate possible enantiomeric inversion. Chiral stability was defined as the retention of at least 90% of the initial concentration of the suspension as the S-enantiomer, the active moiety of Plavix.


RESULTS
Regardless of storage conditions, the oral suspension of clopidogrel retained at least 98% of the active S-enantiomer for 60 days after preparation. Compared with the clopidogrel suspension stored in the refrigerator, more chiral inversion was noted in the clopidogrel suspension stored at room temperature.


CONCLUSIONS
Our investigation of chiral stability indicates that a 5 mg/mL clopidogrel oral suspension stored under refrigeration and at room temperature maintains chiral stability as the active S-enantiomer.
Department of Pharmaceutical, Administrative, and Social Sciences, McWhorter School of Pharmacy, Samford University, Birmingham, Alabama.
Clay R
CR
Tynes
Department of Pharmaceutical, Administrative, and Social Sciences, McWhorter School of Pharmacy, Samford University, Birmingham, Alabama.
Brad
B
Livingston
Department of Pharmacy, Children's of Alabama Health System, Birmingham, Alabama.
Hetesh
H
Patel
Department of Pharmaceutical, Administrative, and Social Sciences, McWhorter School of Pharmacy, Samford University, Birmingham, Alabama.
John J
JJ
Arnold
chiral; clopidogrel bisulfate; compounded oral suspension; enantiomers; high-performance liquid chromatography