FACTOR AFFECTING DISSOLUTION

1. Presented by : Aditya Singh
M.pharm 2nd sem.
1st year
MPH 202T
Integral University

2.  Introduction
 Factors affecting drug absorption

3. Absorption: The process of movement of
unchanged drug from the site of
administration to the systemic circulation.
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4.  Mostly the two factors which affecting the
drug absorption:
 1. Pharmaceutical factors
 A. Physiochemical properties of drug
substances
 B. Dosage form characteristic
 2. Patient-related factor
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5.  Physiochemical properties of drug substances
 1. Drug solubility and dissolution rate.
 2. Particle size and effective surface area.
 3. Polymorphism and amorphism.
 4. Salt form of the drug.
 5. pka of the drug gastrointestinal pH.
 6. Drug stability.
 7. Stereochemical nature of the drug.
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6.  Dosage form characteristics and
pharmaceutical Ingredients :
 1. Disintegration time
 2. Dissolution time
 3. Manufacturing variables
 4. Pharmaceutical ingredient
 5. Nature and type of dosage form
 6. Product age and storage condition
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7.  Age
 Gastric emptying time
 Intestinal transit time
 Gastrointestinal pH
 Disease states
 Blood flow through GIT
 Gastrointestinal contents: food, fluid etc.
 Contact time with gastrointestinal mucosa
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8.  Physiochemical factors :
1. Drug solubility and dissolution rate :the
rate determining step for lipophilic drugs is
dissolution and for hydrophilic is permeation
across the bio-membrane.
2. Particle size and effecting surface area : the
total surface area of any solid surface is called
absolute surface area and the area of solid
surface exposed to the dissolution medium is
called effective surface area.
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9. 3. Polymorphism and Amorphism : when a
substance exists in more than one crystalline
form, known as polymorphism, e.g. barbiturates
and amorphous are supercooled liquid having no
internal structure and greater aqueous soluble
e.g. phenobarbital.
4. Pseudopolymorphism (hydrates & solvates) :
the
solvates exist in different crystalline forms
and the
solvent in association with the drug in water
called
hydrate, e.g. theophylline .
5. Salt form of the drug : some drug are in weak
acids or weak bases so for enhance the solubility
and dissolution rate such drug convert in to salt
forms.
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10. 6. Lipophilicity of the drug : greater
lipophilicity better the absorption.
7. Drug pKa and gastrointestinal pH : the
amount of drug that exist in unionised form is
a function of dissociation constant of the drug
and pH of the fluid at the absorption site.
8. Drug stability : a drug for oral use poor
bioavailability and degradation of drug into
inactive form.
9. Stereochemical nature of drug : 60% chiral
drug is current use and some of in racemic
mixture.
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11. THANKING
YOU….