Sensitive and robust methods for simultaneous determination of beclomethasone dipropionate and formoterol fumarate dihydrate in rotacaps.

Fixed dose combination containing beclomethasone dipropionate (BDP) and formoterol fumarate dihydrate (FFD) is used in the treatment of asthma in form of dry powder inhaler. Two methods are described for the simultaneous determination of BDP and FFD in commercial rotacap formulation. The first method was based on HPTLC separation of the two drugs followed by densitometric measurements of their spots at 220 nm. The separation was carried out on Merck HPTLC aluminum sheets precoated with silica gel 60F254 using hexane:ethyl acetate:methanol:formic acid (2.0:2.5:2.0:0.2, v/v/v/v) as mobile phase. The linearity was found to be in the range of 2.4-8.4 µg/spot and 80-280 ng/spot for BDP and FFD, respectively. The second method was based on HPLC separation of the two drugs on the reversed phase Enable HPLC Analytical C18 G 120Å (250 × 4.6 mm, 5 µm) column at ambient temperature using a mobile phase consisting of methanol:acetonitrile:phosphate buffer adjusted to pH 3.6 using orthophosphoric acid (65:25:10, v/v/v). Quantitation was achieved with UV detection at 220 nm based on peak area with linear calibration curves at concentration ranges of 10-200 and 0.3-6.0 µg/mL for BDP and FFD, respectively. Both methods were validated in terms of precision, robustness, recovery and limits of detection and quantitation. The robustness of both methods was assessed using experimental design and results were analyzed by statistical and graphical approaches. Rotacaps formulation containing BDP (200/400 μg) and FFD (6 μg) were successfully quantified using the proposed methods. The proposed methods can be used as sensitive, precise, accurate and robust methods for quantification of BDP and FFD in Rotacaps.