Rectal absorption of some glycosaminoglycan sulphates and heparin in rats

A standardized extract of glycosaminoglycan sulphates containing heparin, with a low affinity for antithrombin III, and a commercial heparin were administered to rats, by the rectal route. When the glycosaminoglycan sulphates were given in oil emulsion with sodium laurylsarcosinate as surfactant, 1 mg kg-1 and 3 mg kg-1 were sufficient for the clearing and anticoagulant activities, respectively. The rectal absorption of glycosaminoglycans after dosing with a suitable 'promoter' produced dose-dependent effects and their kinetics were comparable to those obtained after intramuscular administration. The oil emulsion improved the bioavailability of glycosaminoglycan sulphates at least 20 times.