Validated Thin-Layer Chromatographic–densitometric and High-Performance Liquid Chromatographic Methods for the Simultaneous Determination of Alfuzosin and Tadalafil in Pharmaceutical Products

The combination of alfuzosin and tadalafil has recently been approved for the treatment of benign prostatic hyperplasia. The investigation of a new separation method for the simultaneous determination of the combination of alfuzosin and tadalafil is thus an essential issue to cover the usual demands of simple analytical methods for routine analysis. Therefore, herein, simple and fast chromatographic methods were established for the simultaneous determination of alfuzosin and tadalafil in pharmaceutical products. Two chromatographic methods, namely thin-layer chromatography (TLC)–densitometry and high-performance liquid chromatography with PDA detection (HPLC–PDA) were developed and validated for the simultaneous determination of the combination of alfuzosin and tadalafil. For the TLC method, separation was achieved on precoated silica gel 60 F254 aluminum plates using dichloromethane–toluene–methanol (7:1:2, V/V) as the mobile phase. The wavelength selected for detection was 235 nm. Concerning the HPLC–PDA method, C18 column (250 mm × 4.6 mm, i.d. [internal diameter], was used with an isocratic elution mobile phase composed of methanol–phosphate buffer (pH 4.5, pH adjusted with orthophosphoric acid) and acetonitrile (5:2:3, V/V) at a flow rate of 1 mL/min and the detection was at 235 nm. The proposed methods were validated in the light of the International Council for Harmonisation (ICH) guidelines, and it was found that the two chromatographic methods are accurate, precise, and linear in the range of 400–2400 ng/band and 20–100 ng for alfuzosin and 200–1200 ng/band and 10–50 ng for tadalafil by TLC and HPLC, respectively. The validated methods succeeded in detecting the cited drugs in pharmaceutical formulation without interference of excipients. Although HPLC is the most applicable method, TLC–densitometry exhibits a superior sensitivity and is cheap and fast, allowing the determination of a large number of samples in due time.