Determination of methylprednisolone and hydrocortisone in plasma using high pressure liquid chromatography.

A method for quantitative determination of methylprednisolone and hydrocortisone in plasma using added methylprednisolone acetate as internal standard and high pressure liquid chromatography is presented. The standard curves were evaluated statistically and logarithmic parabolic equation is preferred over the usual standard curve mathematical relationships. The method was applied to samples of one subject's plasma containing methylprednisolone and endogenous hydrocortisone after oral dosing with multiple doses of methylprednisolone.