TLC analysis of non-steroidal anti-inflammatory drugs and videodensitometric determination of fenbufen in tablets

The chromatographic separation of fenbufen, ibuprofen, ketoprofen, diclofenac sodium, mefenamic acid, and tiaprofenic acid has been investigated. Normal-phase chromatography on silica gel by the ascending and horizontal techniques, and reversed-phase chromatography on octaclecyl-bonded silica gel (RP-18) in horizontal chambers, were performed with suitable mobile phases. The substances were identified by UV illumination at lambda = 254 nm and by use of dyeing reagents. Reversed phase chromatography with phosphate buffer, pH 5.73-10% CTMA-Br in methanol, 3.5 + 6.5 (v/v), as mobile phase enabled better separation of the six drugs than normal-phase mode. A simple videodensitometric TLC method on silica gel RP-18 was developed and validated for quantitative determination of fenbufen in tablets. The limits of detection and quantification were determined by videodensitometry at lambda = 254 nm. A calibration plot was constructed in the range 2.0-12.0 mug/5-muL spot and was linear with a good correlation coefficient (0.9926). RSD for quantitation of fenbufen were from 2.44 to 3.10%. The method was applied satisfactorily to pharmaceutical preparations.