Drugs can be derived from multiple sources, each offering unique chemical entities that can be developed for therapeutic use. The primary sources of drugs include natural, synthetic, and semi-synthetic origins. Natural sources encompass plants, animals, and microorganisms. Plant-derived drugs have historically been significant, with compounds like morphine from *Papaver somniferum* and quinine from *Cinchona* bark being classical examples. Animal sources contribute biologically active substances such as insulin from pancreatic extracts and heparin from porcine intestinal mucosa. Microorganisms, particularly bacteria and fungi, are valuable for producing antibiotics like penicillin and streptomycin. Semi-synthetic drugs are chemically modified derivatives of natural compounds, designed to enhance efficacy, reduce toxicity, or improve pharmacokinetic properties. Synthetic drugs, entirely manufactured through chemical processes, dominate modern pharmacotherapy, with examples including aspirin, paracetamol, and many antihypertensive agents. Additionally, biotechnological sources such as recombinant DNA technology enable the production of complex proteins, vaccines, and monoclonal antibodies, which are critical in contemporary pharmacology. Routes of drug administration refer to the pathways through which drugs enter the body to reach systemic circulation and exert their pharmacological effects. The choice of route is determined by factors such