Medicinal Chemistry I

Catecholamines Biosynthesis (dopamine, norepinephrine, and epinephrine) are synthesized from tyrosine in adrenergic neurons and the adrenal medulla. Steps of Catecholamines Biosynthesis Tyrosine Transport & Hydroxylation: Tyrosine, derived from diet or synthesized from phenylalanine, is transported into neurons. Tyrosine hydroxylase (TH) converts tyrosine into L-DOPA (Rate-limiting step). Decarboxylation to Dopamine: DOPA decarboxylase converts L-DOPA into dopamine. … Read more

Sympathetic Nervous System (SNS) Definition  The Sympathetic Nervous System (SNS) is a division of the autonomic nervous system responsible for the “fight or flight” response. Drugs acting on the SNS either stimulate (sympathomimetics) or inhibit (sympatholytic) its activity by targeting adrenergic receptors (α and β), affecting heart rate, blood pressure, bronchodilation, and metabolic processes. Adrenergic … Read more

Parasympathetic Nervous System (PNS) Definition  The Parasympathetic Nervous System (PNS) are drugs that mimic or enhance the effects. They promote “rest and digest” functions by stimulating muscarinic and nicotinic receptors, leading to effects such as reduced heart rate, increased glandular secretions, and enhanced digestive activity. Cholinergic Agonists (Parasympathomimetics) Mimic acetylcholine, stimulating the PNS. Effects: ↓ … Read more

Neurons and Synapses Definition  neurons and synapses, representing the fundamental unit of neural communication where electrical or chemical signals are transmitted from one neuron to another. It emphasizes the inseparable relationship between the nerve cell (neuron) and its connection point (synapse) in processing and transmitting information within the nervous system. Neurons Neurons are the fundamental … Read more

The nervous system is a complex network of nerves and cells, known as neurons, that transmit signals between different parts of the body. It essentially functions as the body’s electrical wiring. It is divided into two main components: Central (CNS) Peripheral (PNS) This system is fundamental to everything the body does, from sensing heat and … Read more

Factors Affecting Drug Metabolism: It is influenced by biological, chemical, and stereochemical factors, affecting drug efficacy, clearance, and potential toxicity. Biological and Chemical Factors Affecting Drug Metabolism Genetic Polymorphisms Enzyme Variability: Differences in genes encoding drug-metabolizing enzymes (e.g., CYP450) lead to variations in metabolic rates. Metabolizer Phenotypes: Individuals can be poor, intermediate, extensive, or ultra-rapid … Read more

Drug Metabolism Principles Definition  Drug Metabolism Principles: Drug metabolism is the biochemical modification of pharmaceutical substances in the body, primarily carried out by liver enzymes. It occurs in two main phases: Phase I Metabolism Overview: Phase I reactions modify drug molecules via oxidation, reduction, or hydrolysis, often introducing or exposing functional groups (-OH, -NH₂, -SH). Common … Read more

Drug metabolism is the chemical transformation of pharmaceuticals, primarily in the liver, converting lipophilic compounds into water-soluble metabolites for easier excretion. Key Goals of Drug Metabolism Detoxification: Converts toxic compounds into less harmful forms. Excretion: Enhances drug elimination via urine or bile. Regulation of Drug Activity: Activates prodrugs or inactivates drugs, influencing their effect. Enzymatic … Read more

Optical and Geometrical Definition  Optical and Geometrical Isomerism: Stereoisomerism is a form of isomerism in which compounds have the same molecular formula and sequence of bonded atoms (constitution) but differ in the spatial arrangement of atoms or groups. It includes geometrical isomerism, which arises from restricted rotation around double bonds or ring structures leading to … Read more

Bioisosterism Definition: Bioisosterism are structurally similar chemical groups that mimic the biological activity of another. Importance in Drug Design: Improved Activity: Replacement of groups can enhance potency and reduce toxicity. Increased Stability: Bioisosteres improve metabolic stability. Reduced Side Effects: Modification helps improve drug safety. Examples: Sulfonamide (-SO₂NH₂) as a bioisostere of carboxyl (-COOH) in diuretics. Fluorine … Read more