Validated HPTLC method for the simultaneous determination of alfuzosin, terazosin, prazosin, doxazosin and finasteride in pharmaceutical formulations

Abstract

Benign prostatic hyperplasia (BPH) is one of the most common chronic diseases affecting men and it increases in both incidence and prevalence with age. This work presents a simple, sensitive and fast generic high performance thin layer chromatographic (HPTLC) method for the simultaneous determination of five drugs prescribed for the treatment of BPH. These drugs include the α₁-adrenergic blockers; alfuzosin hydrochloride (ALF), terazosin hydrochloride (TER), prazosin hydrochloride (PRZ) and doxazosin mesylate (DOX) in addition to the 5α-reductase inhibitor; finasteride (FIN). The cited drugs were separated on TLC-silica plates using a mobile phase composed of methylene chloride:n-hexane:methanol (8.8:0.3:0.9, by volume). Densitometric analysis was carried out at 254 nm for the α-blockers while FIN was measured at 220 nm. The five drugs were detected at R_f values of 0.26, 0.36, 0.45, 0.59 and 0.69 for ALF, TER, PRZ, DOX and FIN, respectively. The developed method was validated according to the International Conference on Harmonization (ICH) guidelines regarding; linearity, ranges, accuracy, precision, selectivity, robustness and limits of detection and quantification. The proposed method showed good linearity (r > 0.9990) in the ranges; 30–350, 30–350, 20–200, 30–350, 200–2000 ng/spot for the cited drugs, respectively. The applicability of the proposed method was verified through the analysis of laboratory-prepared mixtures and percentage recoveries between 98.27% and 101.97% were obtained. Commercial tablets were also analyzed by the developed methodology with no interference detected from the co-formulated excipients. The high sensitivity, simplicity and selectivity of the proposed method suggest its applicability for routine quality-control analysis purposes of any of the titled drugs in their pharmaceutical preparations.