DEVELOPMENT AND VALIDATION OF UV SPECTROSCOPIC METHODS FOR SIMULTANEOUS ESTIMATION OF SALBUTAMOL SULPHATE AND DOXOPHYLLINE IN COMBINED SOLID DOSAGE FORM

Objective: Salbutamol sulphate (SBS) and doxophylline (DOX) was used for the treatment of asthma and bronchitis. In the present study, two simple, accurate, precise, reproducible and economical UV-spectroscopic methods (A and B) for simultaneous estimation of SBS and DOX in tablet dosage form have been developed.Methods: In the present study the simultaneous estimation of SBS and DOX was carried out by two methods. Method A employs solving of simultaneous equations based on the measurement of absorbance at two wavelengths, 272 nm and 276 nm which are the 𝜆max values of SBS and DOX respectively in phosphate buffer (pH 7.4). Method B is based on the principle of Q-Analysis where in, absorbance was measured at 225 nm (iso-absorptive point, 𝜆1) and 276 nm (𝜆max of DOX, 𝜆2) in phosphate buffer (pH 7.4).Results: Both SBS and DOX shows linearity at all the selected wavelengths and obeys beer’s law in the concentration range of between 0.2-1.6𝜇g/ml and 0.1-3.5μg/ml at 276 nm; 0.2-1.6 µg/ml and 0.1-4.5 µg/ml at 272 nm and 0.2-2.0µg/ml and 0.2-3.5μg/ml at iso-absorptive point 225 nm. Recovery studies for SBS and DOX were performed and the percentage recovery for both the drugs was obtained in the range of 97.45-98.63% (Method A) and 97.49–98.87 % (Method B) confirming the accuracy of the proposed method.Conclusion: Both the methods showed good reproducibility and recovery with % RSD less than 2. Statistical validation of the data shows that the proposed methods can be successfully applied for the routine analysis of drugs in commercial tablets. Hence, it could be used in the analysis of laboratory samples and marketed formulations containing these two drugs in combined dosage form without the interference of common excipients.