Bioanalytical method development and validation for the simultaneous estimation of lamivudine and stavudine in human plasma by HPLC.

Lamivudine (Fig. 1), chemically 2í,3í-dideoxy-3í-thiacytidine, is a pyrimidine analogue, whereas stavudine (Fig. 1), 2í,3í-didehydro-3ídeoxythymidine, is a thymidine analogue. Both are reverse transcriptase inhibitors reported to be active against HIV-1, HIV-2 and hepatitis B virus. (ñ) Enantiomer of lamivudine has less cytotoxic and greater antiviral activity than its (+) enantiomer. It shows synergistic effect with other antiretroviral agents including stavudine, zidovudine and nevirapine (1, 2). Lamivudine and stavudine are the first line regimens in HIV treatment (3). Various methods have been used for quantitative determination of these two drugs individually in the human plasma, such as HPLC and HPLC with tandem MS (4ñ6), but for the combination no such method has been reported yet. The rationale of the present study was to develop an accurate, rapid and economical method for bioanalysis of the above combination of drugs in human plasma (7, 8).