HPTLC-densitometry method development and validation for simultaneous determination of abacavir, lamivudine and zidovudine in combined dosage form

A simple, accurate and precise HPTLC- densitometry method for the simultaneous determination of abacavir, lamivudine and zidovudine in pharmaceutical tablet has been developed. Separation of tablet components was performed on aluminum backed HPTLC plates (silica gel 60 F254 20×20 cm with 0.2 mm thickness, Camag, Muttenz, Switzerland ) using methanol : chloroform : acetonitrile (4 : 8 : 3 v/v). Good sensitivity for all analytes was observed with UV detection at 275 nm. The method was validated for linearity, accuracy, precision, specificity and robustness. The method allowed quantitation over the 200–1450 ng/band range for the three components. Both linear and second order polynomial relationships were studied. Second order polynomial fit was found to be more suitable and its residuals plot showed a much better fitting than that of linear model, indicating good correlation and determinations (r = 0.99995, 0.9998 and 0.9998 and r2 = 0.9999, 0.9997 and 0.9996 for 3-TC, ABC and AZT, respectively). The method has an accuracy of 99.35, 99.19 and 99.13 % for 3-TC, ABC and AZT respectively. The method is robust and has the potential to determine these drug substances simultaneously from the dosage forms.