PHARMACOKINETICS.pptx

This presentation includes the detail information of pharmacokinetics. How body react with drug. Route of drug administration. In this presentation there is a given all the relevant data related to the general pharmacology which is used full for the D. pharm, B. Pharm, Pharm D students . Pharmacodynamics : - What drug does to body.
Pharmacokinetics : - What body does to the drug.
Pharmacotherapeutics : - Use of drugs in prevention & treatment of disease.
Clinical pharmacology : - Scientific study of drugs in man.
Toxicology : - Aspect of pharmacology deals with adverse effects of Drugs.
Pharmacodynamic agents : - Designed to have pharmacodynamic effects in the
recipient.
Chemotherapeutic agents : - Designed to inhibit/kill parasites/malignant cells & does not have or
with minimal pharmacodynamic effects in recipient.
Orphan drugs : - Drugs or Biological Products for diagnosis/treatment/ Prevention of a
rare disease.
E.g.:- Liothyronine (T3), Desmopressin, Baclofen, Digoxin Antibody.PHARMACOKINETICS
Absorption of Drugs:-
A) Simple diffusion: - Bidirectional process rate of transfer across the membrane is proportional to
concn gradient. E.g.:- H20 soluble drugs with low mol-wt, lipid soluble drugs.
B) Active transport: - requires energy – independent of physical properties of membrane. E.g.:- H20
soluble drugs with high mol-wt.
Carrier mediated transport: - E.g.:- Intestinal absorption of Ca2+
.
C) Pinocytosis: - Important in unicellular organisms like Amoeba.
Bioavailability: - Amount of drug reaches systemic circulation following a non-vascular drug
administration.
Auc oral
F = Auc iv
Barriers:-
B.B.B:- made up of choroid cells (strong Barrier).
Testis Barrier: - made up of seroid cells.
Placental Barrier: - made up of sertoli cells (weak Barrier).
Endothelial Barrier: - in all blood cells (very weak).
For absorption of vitB12, IF factor is required which is synthesized by parietal cells?2 types of metabolism: - a. Non synthetic reaction (phase I reaction)
i. Oxidation
ii. Reduction
iii. Hydrolysis
iv. Cyclilization
v. Decyclilization

b. Synthetic reaction (Phase II reaction) conjugation reactions
i. Glucoronide conjugation
ii. Acetylation
iii. Methylation
iv. Sulfate conjugation
v. Glycine conjugation
vi. Glutathion conjugation Remember:- Many drugs are eliminated by the kidney without being.

1. PHARMACOKINETICS BY: - J. Y. Burade (Lecturer) Dr. Rajendra Gode College of Pharmacy Amravati

2. Content Sr. No. Particular 01 Introduction 02 Absorption 03 Bioavailability 04 Distribution 05 Metabolism 06 Excretion

3. Introduction What body does to the drug ? DEF- -- S tudy of movement of drug through body (change in concentration of drug from entry to its exit out of body) . Pharmacon – Drug Kinetics – Movement A lso called ADME study . ADME ABSORPTION DISTRIBUTION METABOLISM EXCRETION DOLO How body reacts with drug?

4. Absorption ABSORPTION –Movement of drug from route of administration into systemic circulation (all the process before drug enters to systemic circulation). Drug transport across the membrane takes place either by passive or active transport. GETTING INTO BODY Weakly acidic drug Unionised form Better absorbed from the stomach in Weakly basic drug Unionised in Better absorbed from the intestine in

5. Factors Affecting Absorption Physical state of drug Liquids are better absorbed than solid. Crystalloids are more readily absorbed than colloids. Aqueous are more quickly absorbed than oily solutions Particle size Smaller particle size se surface area for absorption due to that absorption rate is se. Concentration Higher concentration of drugs aids in better absorption of those drugs. Absorbing surface Absorption rate of gastrointestinal mucosa is more than pulmonary endothelium of skin. Absorption of drugs from highly vascular membrane will be rapid. Larger the surface more is the absorption. Absorption from intestine is more than stomach

6. Functional integrity of GIT pH of Drug Formulation Absorption of drug from the GIT may be effectively sed by se in peristaltic activity. Acidic drugs absorbed from the stomach. E.g., Salicylates and barbiturates. Basic drugs absorbed from the intestine. E.g., Pethidine and ephedrine. Calcium and magnesium ions reduced the absorption of tetracycline. Low degree of ionisation, high lipid/water partition coefficient of non-ionised form and smaller molecular size of water soluble substance , all favours rapid absorption.

7. Bioavailability It is the fraction of a drug that reaches systemic circulation 100 mg 50 mg 50% Bioavailability

8. Factors affecting bioavailability Bioavailability Concentration Particle size Physical state of drugs Dissolution rate Absorbing surface Functional integrity of GIT pH of drug Gastric emptying time Degree of ionization Molecular weight Lipid solubility First pass metabolism Disease state of the gut Formulation

9. Distribution After the drug reaches into the blood circulation it may be distributed to various tissue and organs. Vd = Volume of distribution Vd =  

10. Factors affecting distribution Physiological Factors Physiochemical Properties of Drug Cardiac output Regional blood flow Capillary permeability Tissue volume Special tissue characteristics such as blood brain barrier Binding to plasma proteins Binding to other tissues like fat, liver, bone etc Affinity for tissue constituents Tissue redistribution

11. Metabolism Also called biotransformation 2 types of metabolism: - a. Non synthetic reaction (phase I reaction) i . Oxidation ii. Reduction iii. Hydrolysis iv. Cyclilization v. Decyclilization b. Synthetic reaction (Phase II reaction) conjugation reactions i . Glucoronide conjugation ii. Acetylation iii. Methylation iv. Sulfate conjugation v. Glycine conjugation vi. Glutathion conjugation

12. Factors affecting drug metabolism Genetic Factor Environmental Factor Nutritional status Presence of liver diseases Presence of kidney diseases Drug-food interaction Metabolising enzyme inhibition Metabolising enzyme induction

13. Genetic factors Acetylation of drugs show genetic polymorphism. The individual fall clearly under fast and slow acetylation. Nutritional status of individual Environmental factors Diseases state of individual Drugs or environmental toxins can induce hepatic microsomal enzyme oxidising system or cyp450 resulting into rapid metabolism and elimination of drug. The environmental pollutants like pesticides can induce metabolism. Malnutrition in children and in malnourished elderly, the drug oxidation rate is severely decreased. Whereas high protein diet act as metabolising enzyme inducers. Alcohol consumption have both enzyme induction effect at low dose and at high dose metabolic inhibition effect. Liver being major site of drug metabolism, in patients with liver diseases (cirrhosis) metabolism of drug is severely reduced, resulting in drug toxicity. Similarly in patients with kidney disease; se elimination of drug metabolites is observed.

14. Drug – drug interaction Drug food interaction Simultaneous administration of two drugs causing interaction may show:- Inhibitory effect or stimulatory effect Tyramine present in cheese, bananas may not metabolized by MAO if MAO- inhibitors is given and a severe hypertension crisis may result.

15. Excretion Elimination from body Organs involved in drug excretion Kidneys Lungs Intestines Bile Skin Saliva & Milk Remember:- Many drugs are eliminated by the kidney without being. Renal disease can therefore slow excretion of some drugs

16. REFERENCE Dr. Yadav A. V. , Mrs. Dubal A. S. , Pharmacology, Nirali Prakashan,first edition, June 2022, Page no. :-1.1-1.20 Tripathi K. D., Essentials of medical pharmacology, Jaypee brothers medical,8 th Edition, 2018 Page no. 01-22.

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