Simple Pharmanotes

The history of Chemotherapeutic agents: Bacteria were first identified in the 1670s by van Leeuwenhoek, following his invention of the microscope. This appreciation followed the elegant experiments carried out by the French scientist Pasteur, The possibility that these microorganisms might be responsible for disease began to take hold. During that latter half of the nineteenth century, scientists such as Koch were able to identify the microorganisms responsible for diseases such as tuberculosis, cholera, and typhoid. Methods such as vaccination for fighting infections were studied. Research was also carried out to try and find effective antibacterial agents or antibiotics. However, the scientist who can lay claim to be the father of chemotherapy—the use of chemicals against infection—was Paul Ehrlich. Ehrlich spent much of his career studying histology, then immunochemistry, and won a Nobel prize for his contributions to immunology. By 1910, Ehrlich had successfully developed

After administration a drug has to fight its way for absorption however, various factors affect the rate of absorption they are listed as follows, Physico-chemical, Physiological and Pharmaceutical.     A. PHYSICOCHEMICAL FACTORS: (i) Drug solubility and dissolution rate (ii) Particle size and effective surface area (iii) Polymorphism and amorphism (iv) Pseudo polymorphism (hydrates / solvates) (v) Salt form of the drug (vi) Lipophilicity of the drug – (pH partition hypothesis) (vii) pKa of the drug and pH – (pH partition hypothesis) (viii)Drug stability B. PHYSIOLOGICAL FACTORS These includes factors relating to the anatomic, physiologic and pathologic characteristics of the patient. (i) Age (ii) Gastric emptying time (iii) Intestinal transit time (iv) Gastrointestinal pH (v) Disease states (vi) Blood flow through the GIT (vii) Gastrointestinal contents: a) Other drugs b) Food c) Fluids d) Other normal GI contents (viii) Pre-systemic metabolism by