Growth hormone secretagogues derived from NN703 with hydrazidesas c-terminal.

A series of GH secretagogues based on modifications in the C-terminal of NN703 is reported. The C-terminal N-methyl amide of NN703 has been replaced with alkylated hydrazides in order to decrease the volume of distribution and identify GH secretagogues with shorter duration of action. Most of the prepared compounds show high potency in a rat pituitary assay. Subsequent to an initial in vivo screening in dogs, four compounds were selected for further pharmacological and pharmacokinetic evaluation. The four compounds showed oral bioavailability around 35% and equipotency in vitro compared to NN703. The relationship between lipophilicity and volume of distribution is discussed and it is speculated whether the lower volume of distribution is attributed to the observed higher in vivo potency and shorter plasma elimination half-life.

Absorption, metabolism and excretion of a single oral dose of (14)C-repaglinide during repaglinide multiple dosing.

OBJECTIVE: The present study was designed to assess the disposition of (14)C-repaglinide in whole blood, plasma, urine and faeces, and to measure the total recovery of drug-related material in urine and faeces after a single 2-mg oral dose of (14)C-repaglinide during multiple dosing. METHODS: In this single-centre, open-label, phase-I trial, six healthy male volunteers received 2 mg of the prandial glucose regulator, repaglinide, four times daily for 13 days, 15 min before meals. On the morning of day 7, breakfast was omitted and the dose was given as an oral solution containing 2 mg of (14)C-repaglinide. RESULTS: After oral dosing, a mean peak plasma concentration of repaglinide of 27.74 ng. ml(-1) (range: 16.84-36.65 ng. ml(-1)) was observed with a time to peak concentration of 0.5 h. Approximately 20% of repaglinide and its associated metabolites were distributed into red blood cells. No measurable (14)C-radioactivity was present in whole blood samples 6 h after dosing. Within 96 h of dosing with (14)C-repaglinide, 90% of the administered dose appeared in the faeces and 8% was excreted in urine. In the plasma, the major compound was repaglinide (61%). In the urine, the major metabolites were unidentified polar compounds, the aromatic amine (M(1)) (24%), and the dicarboxylic acid (M(2)) (22%). In the faeces, the major metabolite was M(2) (66% of administered dose). Therefore, repaglinide was excreted predominantly as metabolites and the major in vivo metabolite of repaglinide in humans was M(2). During regular dosing for 6 days, the morning plasma trough levels of repaglinide were, with very few exceptions, almost always too low to measure, indicating the absence of accumulation at this dose of 2 mg four times daily. Repaglinide was well tolerated, and there were no episodes of hypoglycaemia. CONCLUSION: After oral dosing with repaglinide, the mean peak plasma concentration was rapidly attained and, thereafter, plasma concentrations decreased promptly. The major route of excretion was via the faeces. These properties make repaglinide a suitable insulin secretagogue for all patients with type-2 diabetes who retain sufficient beta-cell function.