Low molecular weight heparin (LMWH), a glycosaminoglycan of approximately 6000 molecular weight, is currently used in the prevention of postsurgical thrombosis and in the treatment of deep vein thrombosis. Current dosing regimens entail subcutaneous injections of 2500–5000 anti-factor X a units per day. Transbuccal delivery of LMWH may provide significant advantages over the current injectable dosage forms. The kinetics and extent of LMWH absorption from prototype buccal dosage forms were evaluated. Based on pharmacokinetic analysis, over 3000 anti-factor X a units (i.e., 20 mg) could be delivered from a single application. These results demonstrate the feasibility of administering macromolecular drugs, such as LMWH, via the buccal route.