Development and Validation of Ultraviolet Spectrophotometric Method for Estimation of Bambuterol Hydrochloride in Various Buffer and Solvent Systems

Abstract

Introduction: Bambuterol is a long-acting b2-adrenoceptor agonist used in the treatment of asthma. It is a prodrug of terbutaline. Monograph of bambuterol hydrochloride describes non-aqueous titration for the estimation of bambuterol (B.P., 2001). Till date, simultaneous estimation of bambuterol hydrochloride and montelukast in distilled water, methanol, and chloroform by ultraviolet (UV) spectrophotometric method has been reported. Hence, the proposed method for the estimation of bambuterol hydrochloride in various buffers and solvent system was developed. Materials and Methods: Various solutions used during the study were freshly prepared. Distilled water, hydrochloric acid (Ramkem LR grade), potassium chloride (Qualigens AR grade), potassium dihyrogen phosphate (CDH LR), disodium hydrogen phosphate, sodium chloride (S.D. Fine Chem., extra pure), ethanol (Changshu Hongsheng Fine Chemical, AR), petroleum ether 60–80°C (Qualigen), and isopropyl alcohol (IPA) (Sisco Research Laboratories, extra pure) were used in the study. All the glasswares used were of borosilicate glass and were validated. Bambuterol hydrochloride was purchased from Yarrow Chem Products, Mumbai. UV-1800 Shimadzu spectrophotometer was used for the study. A simple, accurate, precise, and rapid UV spectrophotometric method was developed for the estimation of bambuterol hydrochloride in distilled water, pH 1.2 buffer, pH 6.8 buffer, pH 7.4 buffer, 90% v/v ethanol, IPA, and petroleum ether-ethanol (50%v/v) solution. Results: Bambuterol hydrochloride showed maximum absorbance at 264 nm in distilled water, pH 1.2 buffer, pH 6.8 buffer, pH 7.4 buffer, petroleum ether-ethanol (50%v/v) solution, and maximum absorbance at 265 nm in 90% ethanol and IPA. The proposed method is simple, rapid, and economical and R2 value indicates good linearity. The method was validated statistically (P < 0.05). Further, the drug was found to be stable up to 24 h in various media studied. Conclusion: The method can be useful in the estimation of the content of bambuterol hydrochloride in the raw material and commercial tablet preparation. The method can be applied for the estimation of drug in dissolution studies at gastric and intestinal pH and estimation of drug content in oils and other water immiscible media.