Abstract

The topical lotion of clobetasol propionate was approved for the treatment of psoriasis. Commercially, it is available in the various dosage forms like ointment, cream, foam gel, solution, in various quantities ranges from 0.05 %-0.5 % w/w. The drug is reported in all official pharmacopoeias with their 13 related substances. For the purpose of estimating clobetasol propionate in bulk and formulations using the reversed-phase high performance liquid chromatography technology, an accurate and reliable method was devised. Agilent 1260 Infinity II type high performance liquid chromatography with diode array detector and Phenomenex Luna-C18 column, measuring 250×4.6 mm, 5 µm was utilized in the method. Ammonium acetate buffer, acetonitrile and methanol (60:20:20) made up the mobile phase A combination; acetonitrile and ammonium acetate buffer (20:80) made up the mobile phase B combination. The optimum peak was obtained at retention duration of 15.73 min by maintaining a flow rate of 1.0 ml/min at a wavelength of 240 nm throughout. The percentage error for the instrument, method and intermediate precision was 0.01 %, 0.01 % and 0.02 % respectively. For both method and intermediate precision, the total percentage relative standard deviation was 0.02 %. The procedure was linear and accurate with correlation coefficient of 0.9997 for concentration ranges of 0.05-120 μg/ml with accuracy levels of 0.08 %, 0.02 % and 0.03 % for relative standard deviation of 80 %, 100 % and 120 %. When the drug's stress stability was examined, it was discovered to be unstable under basic conditions, degrading at 99.34 % and under heat conditions, degrading at 14.40 %. Since the established approach is relatively linear and the limits of detection and quantification for clobetasol propionate are very low at 0.93 μg/ml and 2.81 μg/ml respectively, it may be employed in a commercial setting. Retentions were verified and impurities were found for injecting the reference standard. Impurities A, B, J, L and M were found and their retention times were 7.91, 9.28, 18.75, 21.35 and 27.07 min. It was discovered that the approach was accurate and robust.