A complex of glucosamine having a purity of at least about 99 wt. % and a maximum halide content of about 0.01 wt. %, and a therapeutic drug having a pK.sub.a of less than 7. Preferably, the complex is stabilized by coating it with at least one pharmaceutically acceptable polymer comprising a water-soluble, water-immiscible and/or water-swellable homopolymer and/or copolymer. Suitable polymers include carboxypolymethylene homopolymers and copolymers; polyethylene glycol homopolymers and copolymers, povidone homopolymers and copolymers; polyacrylic acid homopolymers and copolymers; polyacrylamide homopolymers and copolymers; polysaccharides; and mixtures of two or more of the foregoing polymers. The resultant coated complex will be stable upon exposure to ambient temperature and/or the atmosphere. Suitable therapeutic drugs fall into the following classes: .alpha.- and .beta.-Adrenergic Agonists; Narcotic and Non-Narcotic Analgesics; Anorexics; Antiallergics; Antianginals; Antiarrhythmics; Antiasthmatics; Antibiotics; Anticoagulants; Anticonvulsants; Antidepressants; Antidiabetics; Antihistaminics; Antihypertensives; Nonsteroidal Anti-Inflammatories; Antimigraines; Antineoplastics; Antiparkinsonians; Antipsychotics; Antipyretics; Antispasmodics; Antithrombotics; Antiulceratives; Anxiolytics; Decongestants; Diuretics; Hepatoprotectants; Sedatives; and Vasodilators.