The kinetics of cathine (d-norpseudoephedrine) describe how the compound is absorbed, distributed, metabolized, and excreted in the body.--- Factors Influencing Kinetics Individual Variability: Genetics, liver enzyme activity, and kidney function affect cathine metabolism and clearance.Renal Clearance: Cathine is partially reabsorbed in the renal tubules depending on urine pH. Alkaline urine increases reabsorption, prolonging its half-life.Absorption Route of Administration: Typically ingested orally or absorbed through mucous membranes (e.g., by chewing khat leaves).Bioavailability: Cathine is well absorbed from the gastrointestinal tract, though its bioavailability depends on the form consumed (fresh khat vs. isolated compound).Excretion Primary Route: Excreted in urine, primarily as unchanged cathine and minor metabolites.CNS Penetration: Crosses the blood-brain barrier, allowing it to exert stimulant effects on the brain.Metabolism Primary Pathway: Metabolized in the liver via oxidation and deamination.Enzymatic Activity: Cathine is processed by enzymes such as monoamine oxidase (MAO), particularly in the liver and brain.Dose-Dependent Kinetics Cathine exhibits linear pharmacokinetics at typical doses.Co-Administration: Combining cathine with other substances (e.g., alcohol or other stimulants) may alter its kinetics and increase the risk of side effects.Distribution Plasma Protein Binding: Cathine has low plasma protein binding, meaning it remains mostly free in the bloodstream to act on target tissues.Volume of Distribution (Vd): Moderate distribution throughout the body, crossing biological membranes to reach the central nervous system (CNS).Active Metabolites: Limited formation of active metabolites compared to its precursor, cathinone.Half-Life: Approximately 3-6 hours, though this can vary depending on individual metabolism and kidney function.Higher doses may lead to a proportional increase in plasma concentrations.Chronic Use: Long-term use can lead to tolerance and altered metabolism.Here's an overview: --- Pharmacokinetics of Cathine 1.Onset of Action: Effects usually begin within 1-2 hours of ingestion.--- 2.--- 3.--- 4.