Stability-indicating spectrophotometric methods for determination of tazarotene in the presence of its alkaline degradation product by derivative spectrophotometric techniques.

The stability of tazarotene (TZ) was investigated and two stability-indicating methods-namely, first derivative and a derivative ratio spectrophotometric method-were used to determine tazarotene in the presence of its alkaline degradation product (HD) using methanol as a solvent. A linear relationship was obtained in the range 1-10 µg ml⁻¹ for both methods. By applying the proposed methods, it was possible to determine tazarotene in its pure powdered from with accuracy 99.35 ± 1.410 (n = 10) for the first derivative method and 99.45 ± 1.053 (n = 10) for the derivative ratio method. First derivative and derivative ratio methods were used for the analysis of laboratory-prepared mixtures containing different ratios of tazarotene and its degradation product and they were valid in the presence of up to 70% and 80% degradation product, respectively. The proposed methods were validated and found to be suitable as stability-indicating assay methods for tazarotene in pharmaceutical formulations.