Validation of a Thin-Layer Chromatography for the Determination of Hydrocortisone Acetate and Lidocaine in a Pharmaceutical Preparation

A new specific, precise, accurate, and robust TLC-densitometry has been developed for the simultaneous determination of hydrocortisone acetate and lidocaine hydrochloride in combined pharmaceutical formulation. The chromatographic analysis was carried out using a mobile phase consisting of chloroform + acetone + ammonia (25%) in volume composition 8 : 2 : 0.1 and silica gel 60F 254 plates. Densitometric detection was performed in UV at wavelengths 200 nm and 250 nm, respectively, for lidocaine hydrochloride and hydrocortisone acetate. The validation of the proposed method was performed in terms of specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, and robustness. The applied TLC procedure is linear in hydrocortisone acetate concentration range of 3.75 ÷ 12.50 g⋅spot −1 , and from 1.00 ÷ 2.50 g⋅spot −1 for lidocaine hydrochloride. The developed method was found to be accurate (the value of the coefficient of variation CV [%] is less than 3%), precise (CV [%] is less than 2%), specific, and robust. LOQ of hydrocortisone acetate is 0.198 g⋅spot −1 and LOD is 0.066 g⋅spot −1 . LOQ and LOD values for lidocaine hydrochloride are 0.270 and 0.090 g⋅spot −1 , respectively. The assay value of both bioactive substances is consistent with the limits recommended by Pharmacopoeia

Effect of UV Irradiation and Temperature on Free Radical Properties in Dehydrocholic and Ursodeoxycholic Acids: An EPR Study

The effect of UV irradiation and temperature on the formation and properties of free radicals in two pharmaceutical important bile acids, such as dehydrocholic (DH) and ursodeoxycholic acids (UDC), was examined. Electron paramagnetic resonance (EPR) spectroscopy was applied to determine the paramagnetic character of UV irradiated and thermally sterilized drugs. Thermal and UV irradiation sterilizations of both compounds were carried out at different conditions according to pharmaceutical norms. The performed EPR measurements of UV irradiated and thermally sterilized DH and UDC samples proved the existence of the complex free radical systems in examined bile acids. Significant influence of UV irradiation in comparison with applied thermal sterilization on free radical concentrations in DH and UDC samples was observed. The results pointed out that thermal method is most suitable for bile acid sterilization. Therefore, this kind of sterilization should be applied in practice