ORAL BIOAVAILABILITY OF HEPARIN USING A NOVEL DELIVERY SYSTEM

Heparin, a large molecule of approximately 20,000 d, was successfully entrapped into biodegradable nanospheres. The final product, at a dose of 2400 U/kg, was given orally with a hydrogel adjuvant to 12 rabbits. Plasma heparin was assayed by use of a validated standard anti-Xa chromogenic method. Elevated levels of plasma heparin were demonstrated for 144 hours after a single oral dose. Oral administration of heparin, heparin with adjuvant, or adjuvant alone (controls) did not result in measurable plasma heparin levels. The nanosphere entrapment of drugs with low bioavailability represents a novel oral delivery system for such agents and confers sustained-release characteristics.