Effect of Solvent: Solvents can change the reaction medium, affecting: Solubility of the drug Polarity of the medium Hydrolysis or oxidation rate Some solvents may stabilize or destabilize the drug. Co-solvent Systems: Adding solvents like ethanol can: Change solvation Affect reaction kinetics Modify degradation pathways Examples: Hydrolysis is faster in aqueous solutions. Adding organic solvents … Read more
Effect of Temperature: As Temperature increases, the rate of degradation increases. Described by Arrhenius equation: $k = A \cdot e^{-\tfrac{E_a}{RT}}$ Where: k = rate constant A = frequency factor Ea = activation energy (J/mol or cal/mol) R = gas constant (8.314 J/mol·K or 1.987 cal/mol·K) T = temperature in Kelvin Implications: Helps estimate shelf life … Read more
Renal Clearance (Clᵣ) explains the volume of plasma cleared of a drug per unit time, key in pharmacokinetics and dosing. Renal Clearance (Clᵣ) is the volume of plasma cleared of a drug by the kidneys per unit time (mL/min or L/h). It evaluates kidney efficiency in drug elimination and helps determine appropriate drug dosing, especially … Read more
Factors Affecting Renal Excretion of Drugs include pH, protein binding, blood flow, drug solubility, and renal function. Factors Affecting Renal Excretion of Drugs Plasma Protein Binding Only free (unbound) drug is filtered. High protein binding may reduce filtration but can still be secreted via active transport. Urine pH and Drug Ionization Weak acids and bases … Read more
Renal Excretion of Drugs involves filtration, secretion, and reabsorption processes that remove drugs through the kidneys. Renal Excretion of Drugs After metabolism (or sometimes directly if they are already sufficiently water-soluble), drugs and their metabolites are excreted from the body. The kidneys are the primary route for most water-soluble agents. Basic Renal Anatomy & Physiology … Read more
Drug Metabolism (Biotransformation) involves enzymatic conversion of drugs into active or inactive metabolites for elimination. Drug metabolism is the enzymatic conversion of drugs into metabolites for easier elimination, primarily occurring in the liver but also in the kidneys, lungs, intestines, and plasma. Phases of Drug Metabolism Phase I (Functionalization Reactions) These reactions introduce or expose … Read more
Apparent Volume of Distribution explains drug distribution between plasma and tissues, guiding dosing and pharmacokinetics. Definition: The apparent volume of distribution (Vd) is a theoretical pharmacokinetic parameter that describes the distribution of a drug in the body. It represents the hypothetical volume in which a drug would need to be evenly distributed to match its … Read more
Plasma Protein Binding of Drugs affects free drug levels, distribution, efficacy, and elimination in pharmacokinetics. Mechanism of Plasma Protein Binding: Reversible Binding: Drugs form non-covalent interactions (e.g., hydrophobic, hydrogen bonding, electrostatic) with plasma proteins, maintaining a dynamic equilibrium between bound and free drug. Competition for Binding Sites: Multiple drugs can bind to the same site, … Read more
Tissue Protein Binding of Drugs influences drug storage, release, duration of action, and overall pharmacological effects. Tissue Protein Binding of Drugs Tissue binding refers to the interaction between drugs and intracellular, extracellular, membrane, or receptor proteins in various organs, affecting drug distribution and elimination. Mechanism of Tissue Protein Binding: Intracellular Binding: Drugs bind to intracellular … Read more
Factors Affecting Protein-Drug Binding include drug concentration, protein levels, affinity, and disease conditions. Protein-drug binding influences pharmacokinetics, pharmacodynamics, and drug efficacy. Several factors determine the extent and specificity of drug binding to proteins. 1. Drug Properties Chemical Structure Size, shape, and functional groups influence binding affinity. Similar drugs may compete for the same binding site. … Read more