Transcript BIOPHARM

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:
A. 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
1. 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?
1. Predicts plasma, tissue and urine drug level with any
dosage regimen.
2. Calculates the optimum dosage regimen for each
patient.
3. Estimates the possible accumulation of drugs.
4. Correlate drug concentrations with pharmacologic or
toxicologic activity.
5. Evaluates differences in the rate or extent of
availability between formulations.
6. Describe how changes in physiology of disease affects
absorption, distribution or elimination of drugs.
7. Explains drug interaction.
Different Compartment Models
A. MAMMILLARY MODEL
1. 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
Highly Perused
Tissue
Slowly Perfused
Tissue
TISSUE GROUP
Heart, kidney,
Brain, Hepatic
portal system
% BODY WT.
9
Endocrine glands,
skin and muscle
56
Adipose tissue and
Marrow
19
Bone,Ligament,Ten
dons, 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)
Polar Compounds
excreted
URINE
Polar Compounds
reabsorb
from the
kidney
FAT TISSUE
DRUG ELIMINATION