Comparative bioavailability study of two haloperidol decanoate containing products

In our hospital pharmacy an injectable solution of haloperidol decanoate 141 mg/ml (equivalent to haloperidol 100 mg/ml) in sesame oil was prepared. The aim of this study was to prove bioequivalence of this formulation with the reference product, Haldol Decanoas. 15 schizophrenic patients, already stabilized with Haldol Decanoas, were enrolled. Intramuscular injections were given every three weeks in the following doses: 100 mg (1 x), 200 mg (7 x) and 300 mg (7 x). In this open, randomized, cross-over study all patients received four injections of the reference product, and four injections of the test product. Only after the fourth injection of each product (when steady-state levels were reached) a concentration-time profile of haloperidol was established during the dose interval of 21 days. The pharmacokinetic parameters AUC0-21 and Cmax were statistically evaluated. Based on these parameters the conclusion was drawn that both products were bioequivalent. The preparation of this injectable haloperidol decanoate solution in our hospital pharmacy amounts to an annual saving of approximately $39,000.