MEKC Determination of Antiretroviral Reverse Transcriptase Inhibitors Lamivudine, Stavudine, and Nevirapine in Pharmaceutical Formulations

A simple, specific, and cost effective micellar electrokinetic chromatographic (MEKC) method for the simultaneous separation and determination of the nucleoside reverse transcriptase inhibitors (NRTIs) lamivudine (3TC), stavudine (d4T) with the non-nucleoside reverse transcriptase inhibitor (NNRTI) nevirapine (NVP) in pharmaceutical formulations has been developed. Analysis was performed in a 75 μm i.d. uncoated fused-silica capillary with 73.5 cm length (effective length 62 cm) using a buffer consisting of 10 mM sodium tetraborate (pH 9.8), 100 mM sodium dodecyl sulfate (SDS) and 15% ( v/v ) 2-propanol. All analytes were separated within 14 min with the applied voltage of +20 kV (current∼65 μA). Samples were injected hydrodynamically by applying 50 mbar pressure for 9 s. The effect of concentration of sodium tetraborate, SDS, 2-propanol, and pH were also studied. The linearity of method was tested over the range of 20–200 μg mL −1 ( r 2 = 0.9996) for 3TC, 5–50 μg mL −1 ( r 2 = 0.9985) for d4T and 25–250 μg mL −1 ( r 2 = 0.9987) for NVP. The developed method was validated in terms of linearity, accuracy, precision, limit of quantitation (LOQ), and limit of detection (LOD). The proposed method was applied for the determination of 3TC, d4T, and NVP drugs in pharmaceutical formulations and recovery was found to be ≥99.20% with the relative standard deviation (RSD) ≤1.55%. The LOQ of the drugs 3TC, d4T, and NVP were found to be 1.8, 2.0, and 1.6 μg mL −1 respectively. In addition, the proposed method was also applied for the detection of thymine impurity, which is a major degradation product of stavudine.