2. Contents
Introduction to Bioavailability
Enhancement of Bioavailability
Approaches used in overcoming Bioavailability Problems
Methods of Enhancing Bioavailability.
3. Bioavailability
It is defined as the rate and extent amount of absorption of unchanged
drug from dosage form.
4. Enhancement of Bioavailability
As far as the bioavailability is concerned, a drug with poor bioavailability is
the one with
Poor aqueous solubility or slow dissolution rate in biological fluid.
Poor permeability through the bio membrane owing to inadequate partition
coefficient or lipophilicity or large molecular size such as that of protein or
peptide drug like insulin.
5. Biopaharmaceutics classification system (BCS)
CLASS SOLUBILITY PERMABILITTY ABSORPTION PATTERN EXAMPLE
1 HIGH HIGH WELL ABSORBED DILTIAZEM
PROPRANOLOL
METOPROLOL
2 LOW HIGH VARIABLE NIFEDIPINE
CARBAMEZAPINE
NAPROXEN
3 HIGH LOW VARIABLE INSULINE
METFORMIN
CIMETIDINE
4 LOW LOW POORLY ABSORB TAXOL
CHLORTHIAZIDE
FUROSEMIDE
6. Approaches used in overcoming
Bioavailability Problems:
The pharmaceutical Approach
The pharmacokinetic Approach
The biological Approach
7. Methods of Enhancing Bioavailability
(The pharmaceutical Approach)
Enhancement of drug solubility or dissolution rate
Enhancement of drug permeability
Enhancement of drug stability
Enhancement of gastrointestinal retentions
8. Enhancement of Drug stability or
dissolution rate
1) Micronization
2) Nano suspension
3) Supercritical fluid process
4) Spray freezing into liquid (SFL)
5) Evaporate precipitation into aqueous solution (EPAS)
6) Use of surfactant
7) Use of salt forms
8) Eutectic mixture
9. Enhancement of drug permeability
Lipid technologies
lon Pairing
Penetration enhancers
10. Enhancement of drug stability
Enteric coating
Complexation
Use of metabolism inhibitors
