The Human Gastrointestinal Track Is A Complex Time

9513 WordsJul 13, 201539 Pages
INTRODUCTION The human gastrointestinal track is a complex time, position, patient-dependent absorptive, metabolizing, and excretive organ. Key of physiological factors that control absorption of drugs from the GIT include gastric, fluid and food intake, bulk fluid and luminal pH, gastric and intestinal secretions, absorptive mechanisms, enterocyte-based metabolism and secretion. Properties of a drug, such as its solubility, stability, ionization, and lipophilicity, strongly influence the rate and extent of drug absorption from GI lumen. Critical assessment of fundamental physicochemical properties and consideration of interplay with physiological constraints of the GIT are paramount to successful design of oral drug delivery systems. Ideal oral extended-release systems rely upon dosage form to control the rate of drug release with no effect from the intrinsic properties of the drug or the conditions prevailing within GIT [1]. In present years, the interest in multiple-layered tablets as an oral controlled release System has increased. Multiple-layered tablets have some advantages Compared to conventional tablets. Commonly used to no chemical Incompatibilities of formulation components by physical separation. Release profiles of drug may depend on combining layers with different release patterns, and by combination of slow-release with immediate-release layers. Conte and Maggi have described an oral controlled-release tablet called Geomatrix, which is based on the
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