ORAL BIOAVAILABILITY OF MORPHINE FROM CON TROLLED-RELEASE FORMULATIONS

The oral bioavailability of morphine following administration of a sin gle dose of 30 mg morphine hydrochloride as Vendal retard film tablets (Lannacher Heilmittel) was investigated and compared with the bioavai lability of morphine following administration of 30 mg morphine sulpha te as Mundidol retard film tablets (Mundipharma). A randomized crossov er study was conducted in 24 male, healthy volunteers. In 6 of them a pilot study with formulations containing 60 mg was conducted. Morphine and its metabolites were quantitated with an immunofluorimetric solid -phase assay (DELFIA). With regard to the following parameters the nov el controlled-release formulation was statistically different from the reference formulation: area under the concentration-time curve, time to maximum and half value duration. After a single dose of the test fo rmulation analgesic serum levels were maintained over a longer lasting period of time than after administration of the reference formulation . The maximal levels in serum and the elimination half life were not d ifferent. From the improved pharmacokinetic parameters of the novel co ntrolled-release formulation an improved clinical efficacy can be expe cted.