Simultaneous spectrophotometric determination of fat-soluble vitamins in multivitamin pharmaceutical preparations

A spectrophotometric method is proposed for the simultaneous determination of vitamins A, D and E in multivitamin pharmaceutical preparations. This is based on multiple linear regression. Most vitamins are directly extracted from the preparations into n-hexane. Microen-capsulated vitamin A preparations require pretreatment of de-encapsulation before the vitamin is extracted. The wavelength range to be used for each preparation and the optimum spectral mode (absorbance or first-derivative) has been chosen in order to assure correct quantitation and avoid interferences from other absorbing species also extracted by n-hexane. The results obtained were validated by simultaneous HPLC analyses for accuracy and precision. © 1995 Springer-Verlag.