Modulation of drug release kinetics from hydroxypropyl methyl cellulose matrix tablets using polyvinyl pyrrolidone.

Hydrophilic matrix tablets are widely used to extend the release of a broad range of pharmaceutically active materials. The mechanism and kinetics of drug release are dependent on the solubility of the active moiety and the swelling and erosion properties of the polymer, with water soluble compounds released predominantly by diffusion. The swelling and erosion properties of hydroxypropyl methyl cellulose (HPMC), typically lead to a first order release rate for water soluble compounds as opposed to the more desirable zero-order kinetics.

Influence of physicochemical properties and intestinal region on the absorption of 3-fluoro-2-pyrimidylmethyl 3-(2,2-difluoro-2-(2-pyridyl)ethylamino)-6-chloropyrazin-2-one-1-acetamide, a water insoluble thrombin inhibitor, in dogs.

In this paper, we describe the physicochemical and biopharmaceutical properties of 3-fluoro-2-pyrimidylmethyl 3-(2,2-difluoro-2-(2-pyridyl)ethylamino)-6-chloropyrazin-2-one-1-acetamide, a direct thrombin inhibitor (1, Fig. 1). Three crystalline forms were characterized and studies were planned to investigate the absorption characteristics of the three selected crystalline forms.