1. Biopharmaceutics and pharmacokinetic by: Anjam Hama A. M. Sc
Biopharmaceutics and pharmacokinetic by: Anjam Hama A. M.Sc. Pharmaceutics HMU/ College of pharmacy
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2. Lecture outline What is Biopharmaceutics?
Factors involve in Biopharmaceutics
Definition of Pharmacokinetic (PK)
Definition of pharmacodynamics (PD)
Aim of PK and PD
Why we study pharmacokinetics?
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3. What is biopharmaceutic?
Biopharmaceutics: the study of how the physicochemical properties of drugs, dosage forms and routes of administration affect the rate and extent of the drug absorption.
Biopharmaceutics: consider the properties of the drug and the dosage form in physiological environment, the drugs intended therapeutic use and the route of administration.
What are those factors have impact on bio pharmaceutics?
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4. Factors involve in Biopharmaceutics
The stability of the API within the drug products
The release of API within the drug products
The rate of dissolution/ release of API with the drug products
The systemic absorption of the API
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5. The study of biopharmaceutic is based on scientific principles and experimental methodology. Study in biopharmaceutics use both invitro and in-vivo method.
In-vivo methods: are more complex studies involving human subjects or laboratory animals. Example ?
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6. Invitro methods: Examples?
They are procedures employing test apparatus and equipments without involving human or experimental animals.
Examples?
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7. Biopharmaceutics pharmacokinetics pharmacodynamic
Kinetics of drug absorption, distribution, elimination (M and E)
pharmacodynamic
Concentration of the drug at the site of action & pharmacological response.
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8. PK and PD PK is the study of what the body does to a drug
PD is the study of what a drug does to the body
ADME: is an acronym in pharmacokinetics and pharmacology for a absorption, distribution, metabolism, and excretion, and describes the disposition of pharmaceutical compound within anorganism.
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9. pharmacokinetic
Pharmacokinetics: is the science of kinetic of drug absorption distribution and elimination (metabolism and excretion).
The study of pharmacokinetic involve both experimental and theoretical approach.
The experimental aspects: involve the development of biological sampling techniques, analytical methods for the measurement of drugs and metabolites and procedure that facilitate data collection and manipulation.
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10. The theoretical aspects of pharmacokinetics involves the developments of pharmacokinetics models that predict drug disposition after drug administration
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11. Absorption: is the process of a substance entering the body.
Distribution: is the dispersion of substances throughout the fluids and tissues of the body.
Metabolism: is the irreversible transformation of parent compounds in to daughter metabolites.
Excretion: Is the elimination of the substances from the body
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12. Absorption Must be able to get medications into the patient’s body.
Drug characteristics that affect absorption:
Molecular weight, ionization, solubility, & formulation
Factors affecting drug absorption related to patients:
Route of administration, gastric pH, contents of GI tract
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13. Absorption in the Pediatric Patient
Gastrointestinal pH changes
Gastric emptying
Gastric enzymes
Bile acids & biliary function
Gastrointestinal flora
Formula/food interaction
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14. Time to Peak Concentration
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15. Distribution Membrane permeability cross membranes to site of action
Plasma protein binding
bound drugs do not cross membranes
malnutrition = albumin =  free drug
Lipophilicity of drug
lipophilic drugs accumulate in adipose tissue
Volume of distribution
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16. Pediatric Distribution
Body Composition
 total body water & extracellular fluid
 adipose tissue & skeletal muscle
 neonates and young infants require larger loading doses of phenobarbital to attain plasma concentrations similar to those in adults.
Protein Binding
albumin, bilirubin, 1-acid glycoprotein reach adult level after one year
Tissue Binding
compositional changes
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17. Metabolism Drugs and toxins are seen as foreign to patients bodies
Drugs can undergo metabolism in the lungs, blood, and liver
Body works to convert drugs to less active forms and increase water solubility to enhance elimination
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18. Metabolism Liver - primary route of drug metabolism
Liver may be used to convert pro-drugs (inactive) to an active state
Types of reactions
Phase I (Cytochrome P450 system)
Phase II
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19. Elimination Pulmonary = expired in the air Bile = excreted in feces
enterohepatic circulation
Renal
glomerular filtration
tubular secretion
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20. Pediatric Elimination
Glomerular filtration matures in relation to age, adult values reached by 3 yrs of age
Neonate = decreased renal blood flow, glomerular filtration, & tubular function yields prolonged elimination of medications
Aminoglycosides, cephalosporin's, penicillin's = longer dosing interval
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21. Effects of age on pharmacokinetic parameters affecting drug disposition
igure 46.1 Effects of age on pharmacokinetic parameters affecting drug disposition. The shadows represent the relative rate of cytochrome P450 (CYP) activity. aUGT (uridine diphosphate glucuronosyltransferase) activity is initially decreased in the infant and reaches adult levels by 4 years of age. bUGT activity is decreased in the elderly only in some drugs but remains approximately the same with others. (From Morselli PL, Pippenger CE. Drug disposition during development: an overview. Am Assoc Clin Chem 1979;1-8, with permission.)
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22. pharmacodynemics
Pharmacodynemics: refers to the relationship between the drug concentration at the site of action (receptor) and pharmacological response, including ( biochemical) and (physiologic) effects that influence the interaction of drug with the receptor. The interaction between the receptor and drug molecules coused the initiating of sequence of molecular events resulting in pharmacological or toxic eresponse.
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23. Why Study Pharmacokinetics (PK) and Pharmacodynamics (PD)?
Individualize patient drug therapy
Monitor medications with a narrow therapeutic index
Decrease the risk of adverse effects while maximizing pharmacologic response of medications
Evaluate PK/PD as a diagnostic tool for underlying disease states
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24. Summery of Drug after administration
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25. References
Applied biopharmaceutics and pharmacokinetics seven addition by leon shargel
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