STABILITY-INDICATING HPLC ASSAY FOR RETINOIC ACID IN HARD GELATIN CAPSULES CONTAINING LACTOSE AND AS BULK DRUG SUBSTANCE

A reversed phase high performance liquid chromatographic assay for det ermination of Retinoic Acid in raw materials and in hard gelatine caps ules containing Tablettose(R) as excipient is described. The method us es a UV diode array detector. The solution concentrations were measure d on weight basis to avoid the use of an internal standard, otherwise necessary for the presence of the undissolved matrix. The study of the recoveries, planned in a Latin square as experimental design, shows t hat the accuracy and precision of the method are excellent. The assay is selective and stability indicating. The method resolves three relat ed substances (13-cis-retinoic acid, 5,6-epoxy-5,6-dihydroretinoic aci d and 4-oxo-retinoic acid) with quantitation in the range 0.04 divided by 0.2 % of the labelled amount of Retinoic Acid (10 mg).