Resin bead detection and spectrophotometric determination of oxyphenbutazone with p-dimethylaminocinnamaldehyde: Application to bulk drug and dosage forms.

An analytical method for resin bead detection and spectrophotometric determination of oxyphenbutazone with p-dimethylaminocinnamaldehyde as a reagent is described. Acid hydrolysed product of oxyphenbutazone produced a red color product with p-dimethylaminocinnamaldehyde that absorbs maximally at 520 nm. The detection limit is 0.8 mug in resin phase and 4.0 mug in aqueous phase. Beer's law is obeyed in the concentration range of 0.4-4.0 mug/ml of oxyphenbutazone. The method is unaffected by the presence of acetylsalicylic acid, salicylamide, phenylbutazone and number of other excipients but paracetamol gives a positive reaction and novalgin being reductone interferes with the test, both should be removed by extraction with dilute sulfuric acid.