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Category Archives: Medicinal Chemistry

Ammonia and Urea Cycle


Ammonia (NH3) is a small metabolite that results predominantly from protein and amino acid degradation. It is highly membrane-permeant and readily crosses epithelial barriers in its nonionized form. Ammonia does not have a physiologic function. However, it is important clinically because it is highly toxic to the nervous system. Because ammonia is being formed constantly […]

Drug Biotransformation Pathways


Pathway 1/Phase 1 Reactions Oxidation is probably the most common reaction in xenobiotic metabolism. This reaction is catalyzed by a group of membrane-bound monooxygenases found in the smooth ER of the liver and other extrahepatic tissues, termed the "cytochrome P450 monooxygenase enzyme system". Additionally, P450 has been called a mixed-function oxidase or microsomal hydroxylase. P450 […]

Factors Affecting Metabolism


Drug therapy is becoming oriented more toward controlling metabolic, genetic, and environmental illnesss rather than short-term therapy associated with infectious disease. In most cases, drug therapy lasts for months or even years, and the problems of drug-drug interactions and chronic toxicity from long-term drug therapy have become more serious. Therefore, a greater knowledge of drug […]