DRUG ABSORPTION
Prepared By:Abhishek Mishra
Chemical Technology(III-year)Pharmaceutical Technology
OutlinePharmacokinetics.Determinants of Drug activity.What is Drug Absorption ??
& its Mechanism..!!!Factor affecting Drug Absorption. Fick’s Law of Diffusion
Pharmacokinetics
Absorption
Distribution
Metabolism(Bio-transformation)
Excretion
Determinants of Drug Activity
Drug Absorption
The translocation(transfer) of drug from the site of administration into the blood-stream
Must be described BOTH in terms of rate and extent
Mechanisms of Drug Absorption
All drug absorption requires crossing of bio membranes
Passive non-ionic diffusion Facilitated diffusion or carrier-mediated
transport Active transport Pinocytosis, endocytosis, phagocytosis
Factors Determining the Rate and Extent of Drug
Absorption Physicochemical properties of the drug
– Stereo chemical properties– Solubility
Molecular size Dosage form and delivery system Vehicles Dose
Cont’d
Route and site of administration Contact time with absorptive
surface pH at site of absorption Integrity of the membrane Vascularization and blood flow at
absorptive site
Fick’s Law of Diffusion
Rateof
Penetration
PartitionCoefficient
MembraneThickness
DiffusionCoefficient[ [] ]x
[ ]= x Surface
Area[ ] Concen-tration
Gradient[ ]x
Solutions> Emulsions> Suspensions> Capsules> Tablets> Coated Tablets> Enteric Coated Tablet> Sustain Release Tablet
Order of Drug Absorption
Thank You