Chromatographic Method for Quantification of Tenofovir in Pharmaceutical Formulations: Comparison with Spectrophotometric Method

Aims: An efficient therapeutic drug or antiviral agent to treat Covid-19 is still not available. But, previously licensed pharmaceuticals to treat other virus infections are usedon an off-label basis either alone or in combination. Tenofovir emerged as a promising treatment for Covid-19 in September 2020. It is an antiretroviral drug that is active against many viruses. This study explains the development and asessment of liquid chromatographic and UV spectrophotometric methods to quantify tenofovir in raw materials and tablets.

Methods: HPLC analyzes were performed using a C18 column and a mobile phase composed of 20 mM KH2PO4, with a flow rate of 0.8 mLmin-1 and UV detection at 260 nm. For the spectrophotometric analyzes, ultra-pure water was used as a solvent. UV spectrum of standard and sample solution were recorded between 200 and400 nm and Tenofovir was detected using a wavelength of 260 nm. Both methods have been validated according to the procedures described in ICH guidelines Q2(R1) for the validation of analytical methods.

Results: The results showed that both spectrophotometric and liquid chromatographic methods were linear, precise, accurate, rugged and robust with relative standard deviation R.S.D.% values less than 1%, and the recovery percentage was within standard limits (98-102%). Then a statistical comparison of these two analytical methods was performed, and the results of both methods showed no significant difference. It was found that both methods were not statistically significant with respect to each other in the 95% confidence interval (p<0.05). As a result, the proposed methods were found to be highly effective and could be used for routine analysis of tenofovir in pharmaceutical formulations.