BIOPHARMACEUTICAL CLASSIFICATION SYSTEM

MD. TAJUL ISLAMROLL – 23

BATCH – 10TH

• Drug is any substance that is capable of altering physiological activity.

• Biopharmaceutics is the study of physical and chemical properties of drugs and their proper dosage relating onset, duration and integrity of drugs.

Concept

• They are on the basis of – Solubility– Permeability– Dissolution

Solubility is the ability of the drugs to be solution after dissolution.

Permeability of the drug to pass the biological membrane which is lipophilic.

BCS

• Aqueous solubility-Solubility in aqueous solvent (H2O, water miscible solvents)

• Partition-co-efficient-Fatty solvent (water immiscible)

Solubility

• Drugs molecules pass the biological membrane by

-Active transport-Passive transport

Simple diffusion

Osmosis/ Pore transport

-Carrier mediated facilitated diffusion-Vesicular transport

PhagocytosisPinocytosis

Permeability

• To assess the relationship between in vitro dissolution characteristics and in vivo absorption performance of immediate-release (IR) products

• To evaluate the feasibility and appropriateness of an extension of the biowaiver concept.

Objects

Class Solubility Permeability

Class - 1 High High

Class – 2 Low High

Class – 3 High Low

Class - 4 Low Low

Classification

• Drugs dissolved rapidly• Drugs absorbed rapidly• Rapid therapeutic action• Excellent property• Ideal for oral route• Ex - Metoprolol

Class - 1

Class - 2• Drugs dissolve slowly• Drugs absorbed rapidly• Controlled released drugs• Oral / IV route for administration• Ex. Glibenclamide, Ezetimibe

Class - 3• Dissolved rapidly• Absorbance is limited• Incomplete bioavailability• Oral / IV route for administration• Ex. Cimetidine

Class - 4• Low dissolution rate• Low permeability property• Slow or low therapeutic action• IV or other routes are required• Ex. Hydrochlorothiazide

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