Simultaneous TLC-densitometric determination of tamoxifen citrate and medroxyprogesterone acetate and UV-degradation kinetic study of medroxyprogesterone acetate

Coadministration of tamoxifen citrate (TMC) and medroxyprogesterone acetate (MPA) is preferred to increase the response rate and the percentage recovery in patients with endometrial carcinoma. Administration of TMC and MPA and their combination affects estrogen and progestin receptor concentrations in advanced endometrium carcinoma by affecting 17 beta-hydroxyl steroid dehydrogenase activity and serum hormone concentrations. A sensitive, accurate and robust thin-layer chromatography method has been established for simultaneous analysis of TMC and MPA. Method development was carried out on silica gel F-254 using butanol-acetic acid-water (6:0.5:0.5, v/v/v) as mobile phase. Densitometric scanning was carried out at 241nm for simultaneous detection of TMC and MPA. Retardation factor (R-f) values for TMC and MPA were 0.21 and 0.85, respectively. The method was validated according to ICH guidelines. Regression plots revealed linear relationships in the concentration range of 50-500 and 25-250 ng/band for TMC and MPA, successively. Accuracy was >= 99.60 and 98.72% for TMC and MPA, respectively. Forced degradation studies using UV photodegradation was applied on MPA after exposure to UV light for different times and applying a kinetic study for calculating the degradation rate constant (k) and half-life time (t(1/2)).