Abstract
OBJECTIVES: Tiotropium (TIO) and formoterol fumarate (FF) combination in dry powder inhaler (DPI) dosage form used for treating asthma, bronchospasm, chronic bronchitis, emphysema and chronic obstructive pulmonary diseases. Aim to develop an analytical method for estimating emerging and advancing dry powder inhaler combination toward 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 reverse phase-high performance liquid chromatography (HPLC) method has been developed for the determination of related substances in FF and TIO DPI. MATERIALS AND METHODS: The analytical method was performed on schimadzu HPLC with a quaternary pump, the separation achieved using BDS Hypersil C18 (250×4.6 mm, 5 μm) column with mobile phase consisting of sodium phosphate buffer pH 3.2 and acetonitrile 1.0 mL min-1 flow rate in the gradient elution. Diluent consists of a mixture of buffer pH 3.2 and acetonitrile in the ratio of (70:30) %v/v. 30°C column temperature and photodiode-array detection detector at a wavelength 240 nm. The run time was 50 min. The Retention time of FF and TIO was found to be at 7.8 and 10.3 min respectively. RESULTS: Both the analyte peaks were found to be free from interference. The method was validated as per the International Council on Harmonisation guidelines, the linearity was performed on 0.015 to 1.089 ppm for TIO and 0.01 to 0.728 ppm for FF concentration with correlation coefficient of 1,000. The precision and accuracy were also performed at the limit of quantification level were within the limits. Forced degradation study was also conducted. CONCLUSION: The recommended method for the related substance determination of FF and TIO is simple, selective, specific and precise. It also demonstrates the study of the degradation pattern. Moreover, the above developed related substance analytical method was applied to the bulk analysis and pharmaceutical dosage form for routine analysis and stability study.