SPECTROPHOTOMETRIC METHOD FOR DEGRADATION STUDY OF TENOFOVIR DISOPOXIL FUMARATES

Spectrophotometric method for degradation study of Tenofovir disoproxil fumarate was described.  The ultra violet spectrum of both acidic and basic degraded product was found to substantial difference from pure drug. The extent of degradation can be calculated by comparing the decrease in absorbance at selective wavelength. The zero order UV spectrums of TDF showed maximum absorbance at 260nm and at 220nm. The solution in NaOH did not show any absorbance at 220 nm in zero order spectrums and showed decrease in absorbance at 260nm. So the decrease in absorbance at 260 nm was used as measure of extent of degradation in NaOH. In case of HCl degradation also decrease of absorbance is seen due to degradation but in comparison to NaOH degradation is lesser. Absorbance is seen at 260nm in zero order spectrums and there is no peak observed at 220nm. In case of HCl degradation also decrease of absorbance is seen due to degradation but in comparison to NaOH degradation is lesser. Absorbance is seen at 260nm in zero order spectrums and there is no peak observed at 220nm. In the basic degradation study it is found that Tenofovir disoproxil fumarate is more sensitive to alkaline hydrolysis. The 20.49% of drug is degraded if treated with 0.1N sodium hydroxide. The degradation is somewhat slower in acidic conditions as 13.17% of drug is degraded if treated with 0.1N hydrochloric acid. The relative standard deviation (RSD) of both alkaline and acidic degradation was found to be less than 2% which indicate that method is reproducible. The LOD and LOQ for TDF was found to be   0.104, 0.319 and 0.211, 0.639 µg ml^-1 at 260nm and 220nm respectively indicates the method is sensitive.