Quantitative Determination of Related Substances in Formoterol Fumarate and Tiotropium in Tiomate Transcaps^® Dry Powder Inhaler

Tiotropium (TIO) and Formoterol fumarate (FF) combination in dry powder inhaler dosage form used in the treatment of asthma, bronchospasm, chronic bronchitis, emphysema and chronic obstructive pulmonary diseases (COPD). Aim to develop an analytical method for the estimation of emerging and advancing dry powder inhaler combination towards enhanced therapeutics for the estimation of related substances but for this it is foremost to have a sensitive, simple, robust and validated method therefore, a new RP-HPLC method has been developed for the determination of related substances in Formoterol fumarate and Tiotropium in Formoterol fumarate dihydrate and Tiotropium bromide dry powder for inhalation. The chromatographic separation utilises an gradient elution in which buffer solution pH 3.2 used as mobile phase A and acetonitrile as mobile phase B at 1.0 mL min−1 flow rate, 30ºC column temperature, and PDA detector at wavelength 240nm and Hypersil BDS C18 column (250 x 4.6mm, 5μm). Being validated in accordance with ICH guidelines, this method provides a safer and easier solution for QC testing and Stability studies for the related substances test.