Described herein is a drug delivery system, which is based on a novel polymer namely hypromellose-graft-chitosan (HC), useful to deliver a drug to a patient in sustained and controlled release fashion. HC is highly water soluble across the pH range from 1.2 to 10, and has a high pH buffering capacity to provide a pH-stable environment for drug delivery. In addition, the drug delivery system provided herein exhibited a drug loading efficiency of over 90% in all drugs tested, which is 1-2 fold higher than the efficiency attainable by conventional chitosan, and achieved a 2-3 fold longer duration of sustained drug release.L'invention concerne un système d'administration de médicaments basé sur du chitosane greffé d'hypromellose (HC) utile pour administrer un médicament à un patient de manière prolongée et contrôlée.
