Biopharmaceutics refers to the relationship of the: * physicochemical property of the drug * dosage form in which the drug is given * route of administration *extent of systemic absorption of the drug involves factors that influences the: * protection of the activity of drug * release of drug from the drug product * rate of dissolution of drug at the absorption site

PHARMACOKINETICS -involves the kinetics of drug liberation, absorption, distribution, elimination and response or the LADMER system. Liberation- determines the onset of action, rate of absorption and availability of all routes of administration, except IV. Tablet dissolution is the ability of a drug preparation to dissolve. (insert diagram)

Pharmacokinetics involves: Experimental Aspect - development of biological sampling techniques analytical methods for the measurement of drug and metabolites procedures that facilitate data collection and manipulation B. Theoretical Aspect - development of pharmacokinetic models that predict drug disposition after drug administration.

is a hypothesis that uses mathematical terms that concisely describe quantitative relationships. Describes complex biologic system concerning the movement of drugs Used to simulate the rate processes of drug absorption, distribution and elimination. Describes the drug concentration in the body as a function of time.

Pharmacokinetic Models Empirical Model - are practical but not very useful in explaining the mechanism of the actual process by which the drug is absorbed, distributed and eliminated in the body. 2. Physiological Model - interpolates the data and allow a formula to estimate drug levels over time when limited information is available. - it reveals an organ specific or sub-organ regional information and assume that the plasma drug concentration globally within the body.

Why Molecular Models are being used? Predicts plasma, tissue and urine drug level with any dosage regimen. Calculates the optimum dosage regimen for each patient. Estimates the possible accumulation of drugs. Correlate drug concentrations with pharmacologic or toxicologic activity. Evaluates differences in the rate or extent of availability between formulations. Describe how changes in physiology of disease affects absorption, distribution or elimination of drugs. Explains drug interaction.

Different Compartment Models A. MAMMILLARY MODEL One-Compartment Open Model through IV - is the simplest way used to describe the process of drug distribution and elimination of the body. 2. Multi-Compartment Model - highly perfused tissue and blood makes up the central compartment.

Different Compartment Models B. CATENARY MODEL - consist of compartments joined to one another like the compartments of a train. C. PHYSIOLOGIC/FLOW/PERFUSION MODEL - based on the known anatomic and physiologic data.

GENERAL GROUPING OF TISSUE ACCORDING TO THE BLOOD SUPPLY BLOOD SUPPLY TISSUE GROUP % BODY WT. Highly Perused Tissue Heart, kidney, Brain, Hepatic portal system 9 Endocrine glands, skin and muscle 56 Adipose tissue and Marrow 19 Slowly Perfused Tissue Bone,Ligament,Tendons, Cartilage, Teeth and Hair 22

DISTRIBUTION What happened to the medicine after it is absorbed? A D M E Absorption Metabolism Excretion Distribution (tissue bound)

DRUG ELIMINATION Polar Compounds Polar Compounds reabsorb from the kidney excreted URINE FAT TISSUE DRUG ELIMINATION