QUANTITATIVE ESTIMATION OF ASPIRIN DRUG BY USING UV VISIBLE SPECTROSCOPY

The quantitative estimation of Acetylsalicylic acid present in the marketed tablet formulation was carried out successfully using UV–Visible spectrophotometry, which is based on the measurement of absorbance of ultraviolet radiation by the analyte at a specific wavelength. The standard drug solution exhibited maximum absorbance at a wavelength (λmax) of approximately 275 nm, which was selected for further analytical measurements. A series of standard solutions of varying concentrations were prepared accurately, and their absorbance values were recorded using a UV– Visible spectrophotometer against a suitable blank. These absorbance values were plotted against the corresponding concentrations to obtain a calibration curve, which demonstrated a linear relationship over the selected concentration range. This linearity confirms the applicability of BeerLambert Law, which states that the absorbance of a solution is directly proportional to its concentration, provided the system follows ideal conditions. The regression analysis of the calibration curve showed a high correlation coefficient (close to 1), indicating excellent linearity and reliability of the analytical method. The slope and intercept obtained from the calibration curve were used to determine the concentration of acetylsalicylic acid in the sample solution prepared from the marketed tablet. The sample preparation involved accurate weighing, crushing of tablets, dissolution in a suitable solvent, filtration to remove insoluble excipients, and appropriate dilution to bring the concentration within the linear range of the calibration curve. The absorbance of the sample solution was measured under identical experimental conditions, ensuring consistency and minimizing variability. The calculated concentration of acetylsalicylic acid in the marketed formulation was found to be very close to the labelled claim, and the percentage purity was within the acceptable pharmacopoeia limits (typically ranging between 95% and 105%). This indicates that the marketed product complies with quality standards and contains the appropriate amount of active pharmaceutical ingredient. The results obtained demonstrate good accuracy and precision of the method, as evidenced by minimal deviation between experimental and theoretical values.