Analysis of spironolactone in compound powder by ultraviolet-visible spectrophotometry

Abstract

Introduction. Spironolactone (Spir) is a selective and competitive antagonist of aldosterone that increases the excretion of water and sodium while decreasing the excretion of potassium (K+ sparing diuretic). The substance was studied to develop qualitative and quantitative methods of analysis and to validate them according to documents regulating the quality of active pharmaceutical ingredients in the development of pharmaceutical forms. Material and methods. A new dosage form (powder) with Spir was developed and analyzed by a spectrophotometry method using a UV-Vis spectrophotometer (Agilent 8453, USA) with 10.0 mm matched quartz cells at 238±2nm, with methanol as the blank. The method was validated for specificity, linearity, precision, accuracy, robustness, LOD and LOQ. Results. The method was found to be linear in the drug concentration range of 5.0 to 30.0 μg/ml, with a correlation coefficient (R2 ) of 0.9994 for Spir. The LOD of Spir was 0.5 μg/ml and the LOQ was 1.4 μg/ml, indicating the method’s sensitivity. The method was established as accurate (mean recovery values of concentration at 80%, 100%, 120% ranging between 99.9 and 101.7%). Repeatability precision and intermediate precision %RSD values amongst six sample solutions were from 0.13% to 0.25% for Spir (less than 2%). The accuracy (recovery) ranged between 99.9% and 101.7%, with standard deviations ranging from 0.08% to 0.17%. Conclusions. In the presence of common excipients, such as microcrystalline cellulose, lactose monohydrate, and stearic acid, no interferences were observed. This method was found to be suitable for the routine analysis of Spir from the newly developed pharmaceutical form.