An experimental animal model for studying the effects of a novel lymphatic drug delivery system for propranolol

Abstract

An experimental model using the anaesthetised pig is described which allowed the simultaneous collection of mesenteric lymph, hepatic portal blood and systemic blood samples. The levels of propranolol observed in lymph reached 103 ng/ml after intraduodenal administration of a standard preparation of the drug at a dose of 2 mg/ml. Dosing with a novel lymphatic drug delivery system containing an equivalent dose of the drug resulted in a lymph propranolol concentration of 278 ng/ml. Peak lymph propranolol levels with each delivery system occurred within 15 min of dosing and then rapidly declined. The hepatic portal blood concentrations of propranolol were initially lower than those observed in lymph in all cases and only equalled or exceeded peak lymph levels 30 min after dosing. The early appearance of propranolol in the systemic circulation is consistent with direct delivery from the lymphatic system.