Development and Validation of a RP-HPLC Method For the Interaction Studies of Metformin and Clindamycin in Human Plasma

Background: Metformin is mostly prescribed with clindamycin in the treatment of diabetic disease with bone, joint and lower respiratory infections. The interaction of the two drugs is yet known. This study was aimed at developing and validating a simple and reproducible RP-HPLC method for the interaction Studies of Metformin and Clindamycin in Human- Plasma.

Methods: The study was designed in two phases. Phase one, all volunteers received 1 g metformin; in phase two, it was co-administered with clindamycin (500 mg). In each phase blood samples were collected at intervals within 24 h post-drug administration. Plasma samples were acidified with HCl, deproteinized with acetonitrile and centrifuged, the supernatant was washed with dichloromethane and injected into the HPLC system.

Results: Chromatographic separation was achieved in 10 minutes with metformin and phenytoin having retention times of 2.230 and 4.407 minutes respectively. The method was precise (3.43% RSD), accurate (% Er of 2.24 and % recovery of 96.52%), with a linear calibration curve (r = 0.995.). LOD and LOQ of the developed method were 0.02 and 0.05 ?g/mL respectively. All the parameters were within the acceptable limits.

Conclusion: From the result the developed and validated method was accurate and suitable for routine analysis of metformin in human plasma. It was also concluded that metformin may be co-administered with clindamycin to type 2 diabetic patients with caution to avoid the possible risk of toxicity or therapeutic failure.