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