Application of orthogonal functions to the determination of prednisolone and hydrocortisone in some pharmaceutical preparations.

: Glenn's method of orthogonal functions has been successfully applied to the direct spectrophotometric determination of the title compounds in presence of phenylephrine and/or neomycin sulphate without preliminary separation. The proposed methods when applied to the analysis of market preparations are in good agreement with those of the triphenyltetrazolium colour reaction recommended as the official method.