Mexiprostil

Nephrotoxicity is the most troublesome side effect of cyclosporin A (CSA) therapy. In vitro studies have shown that verapamil and PGE analogues can protect human and rat kidney allografts and murine pancreatic B cells from CSA cytotoxicity. The LLC-PK.1 pig kidney cell line has recently been shown to be a use-ful in vitro model system for studying CSA nephrotoxicity. We have adopted the MTT assay to assess the effects of CSA on LCC-PK.1 cell growth and have examined the effects of verapamil and MDL 646, a cyto-protective PGE1 analogue, on CSA nephrotoxicity. The results show that neither compound prevents the cytotoxic effects of CSA on kidney cells.

The effects of single oral doses of 800 and 1200 micrograms of the new alprostadil analogue mexiprostil (prostaglandin E1 16-methyl-16-methoxy derivative, MDL 646), presented as tablet and capsule formulation, on basal and pentagastrin-stimulated acid secretion, were studied in 10 healthy volunteers, using a randomized, double-blind, placebo-controlled, 5-way crossover design. Compared to placebo, administration of mexiprostil resulted in a significant inhibition of basal gastric acid secretion, at both doses and formulations. Pentagastrin-stimulated gastric secretion was reduced to a lesser degree and the differences compared to placebo did not achieve statistical significance when adjustments were made for basal effects present before starting stimulation. Total volume of gastric secretion, under basal conditions, was decreased by both doses and formulations, though the changes were significant only at 1200 micrograms for both formulation. The decrease in volume of gastric secretion during pentagastrin infusion did not reach statistical significance. Basal intragastric pH was increased by both doses and formulation, but the changes were significant only for the capsule formulation, at either dose. Neither dose of mexiprostil prevented the decrease in intragastric pH produced by pentagastrin infusion. Tolerability of mexiprostil was excellent with no unwanted effects reported either during or after the study. No changes in heart rate and systemic blood pressure were observed. Laboratory safety parameters were not altered by mexiprostil. There was no significant difference between the effects of both formulations of mexiprostil on any pharmacodynamic parameter.