[Pharmacokinetics of hypoglycemic sulfonamides: Ozidia, a new concept]

Hypoglycaemic sulfonamides differ in their properties, which vary in clinical importance. The potency of sulfonamide has increased with the generations. However, this potency is compensated in practice by the dose prescribed, which is much smaller for recent generations. The half-life is a far more important property. The effective action period is correlated with half-life but is much longer. The action period for "short-term" sulfonamides is < or = 24 h (tolbutamide, glipizide) and can exceed 24 h for "long-term" sulfonamides (e.g. glibenclamide). Metabolism and elimination reduce the risk of accumulation. All sulfonamides are metabolised more than 95% by the liver. The metabolites are inactive except for one from glibenclamide. As a function of their action period and possibly of intrinsic properties, some sulfonamides more than others (e.g. glibenclamide) affect fasting hepatic glucose production, which is particularly increased early in the day in non-insulin-dependent diabetic patients because of a circadian drop in insulin sensitivity (dawn phenomenon). Finally, in chronic administration, all sulfonamides cause a progressive desensitisation of the beta cell, which responds by an insulin secretion peak only during food intake. This condition indicates the unuselessness of sulfonamide fractionation and, contrary to the classic notion, the low risk of hypoglycaemia after a meal is skipped. The ideal product would be a sulfonamide with high potency and an ultra-short half-life, but capable of maintaining plasma concentrations for 24 h (which might seem incompatible except in continuous administration). Moreover, it would exert its action at relatively low levels of insulinaemia and be completely metabolisable. Glipizide in its osmotic oral form (Ozidia) satisfies all these conditions since it is a very potent sulfonamide with a quite short half-life but with intestinal delivery up to 16 h after administration because of its osmotic principle. It controls fasting glycaema better than ordinary glipizide and at least as well as glibenclamide by acting on hepatic glucose production. Compared to glibenclamide, it has the advantage of generation this effect at lower levels of insulinaemia. In comparison with normal glipizide, it allows identical control for lower postprandial inslinaemias, which is proof of its powerful inductive effect on insulin sensitivity.