Third-order derivative UV spectrophotometry and densitometry for the simultaneous assay of acetylsalicylic acid and salicylic acid in tablet formulations

Abstract

Third-order derivative spectrophotometry is proposed for simultaneous determination of acetylsalicylic acid and free salicylic acid in sustained-release tablets, and compared with TLC-densitometry. Both methods were evaluated through selectivity, and accuracy tests. Results for acetylsalicylic acid and salicylic acid in aspirin sustained-release tablets showed good agreement.