4. Dosage Form Design: Biopharmaceutic and Pharmacokinetic considerations
4. Dosage Form Design: Biopharmaceutic and Pharmacokinetic Considerations
Contents General principles of drug absorption Il. Dissolution and drug absorption III. Bioavailability and bioequivalence Iv. Routes of drug administration V. Fate of drug after absorption VI. Pharmacokinetic principles
Contents I. General principles of drug absorption II. Dissolution and drug absorption III. Bioavailability and bioequivalence IV. Routes of drug administration V. Fate of drug after absorption VI. Pharmacokinetic principles
Biopharmaceutics is the area of study embracing the relationship between the physical, chemical, and biological sciences as they apply to drugs, dosage forms, and to drug action. (生物药剂学是围绕物理学、化学和生物科 学及它们关于药物、剂型和药物作用相互 关系的研究领域。)
Biopharmaceutics is the area of study embracing the relationship between the physical, chemical, and biological sciences as they apply to drugs, dosage forms, and to drug action. （生物药剂学是围绕物理学、化学和生物科 学及它们关于药物、剂型和药物作用相互 关系的研究领域。）
For a drug to exert its biological effect, it must be transported by the body fluids, traverse the required biological membrane barriers, escape widespread distribution to unwanted areas, endure metabolic attack,(经受代谢改变) penetrate in adequate concentration to the sites of action, a interact in a specific fashion a causing an alteration of cellular function
For a drug to exert its biological effect, it must be ◼ transported by the body fluids, ◼ traverse the required biological membrane barriers, ◼ escape widespread distribution to unwanted areas, ◼ endure metabolic attack, （经受代谢改变） ◼ penetrate in adequate concentration to the sites of action, ◼ interact in a specific fashion, ◼ causing an alteration of cellular function
Oral administration Gastrointestinal tract Dru Intravenous injection Circulatory systems D 會又 Intramuscular injection Tissues Metabolic sites Drug Subcutaneous injection metabolites ious roule schematic representation of events of absorption, metabolism, and excretion of drugs after their administration by var
The area of study which elucidates the time course of drug concentration in the blood and tissues is termed pharmacokinetics a It is the study of the kinetics of absorption, distribution, metabolism and excretion (ADME) of drugs and their corresponding pharmacologic, therapeutic, or toxic response in animals and man a Pharmacokinetics also may be applied in the study of interactions between drugs
◼ The area of study which elucidates the time course of drug concentration in the blood and tissues is termed pharmacokinetics. ◼ It is the study of the kinetics of absorption, distribution, metabolism and excretion (ADME) of drugs and their corresponding pharmacologic, therapeutic, or toxic response in animals and man. ◼ Pharmacokinetics also may be applied in the study of interactions between drugs
I General principles of drug absorption Body membranes are generally classified as three main types those composed of several layers of cells, as the skin those composed of a single laver of cells, as the intestinal epithelium those of less than one cell in thickness, as the membrane of a single cell
I. General principles of drug absorption Body membranes are generally classified as three main types: - those composed of several layers of cells, as the skin, - those composed of a single layer of cells, as the intestinal epithelium, - those of less than one cell in thickness, as the membrane of a single cell
In most instances a drug substance must pass more than one of these membrane types before it reaches its site of action
In most instances a drug substance must pass more than one of these membrane types before it reaches its site of action
Drugs are thought to penetrate these biologic membranes in two general ways: )by passive diffusion 2) through specialized transport mechanisms
Drugs are thought to penetrate these biologic membranes in two general ways: 1) by passive diffusion 2) through specialized transport mechanisms
1) Passive diffusion Passive diffusion is used to describe the passage of (drug) molecules through a membrane which behaves inertly in that it does not actively participate in the process a Drugs absorbed according to this method are said to be passively absorbed
1) Passive diffusion ◼ Passive diffusion is used to describe the passage of (drug) molecules through a membrane which behaves inertly in that it does not actively participate in the process. ◼ Drugs absorbed according to this method are said to be passively absorbed