drug absorption the very basis of pharmacokinetics

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2. DRUG ABSORPTIONDr. Vaneet Aggarwal
P.G. In Pharmacology
Department of Pharmacology
JJM Medical College
Davangere
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3. DRUG ABSORPTION
1.Definition
2.Biological Membrane
3.Mechanisms in Drug Transport
4.Drug Absorption through various routes
5.Factors affecting drug absorption
6.Altering drug absorption
7.Bioavailability
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4. BIOLOGICAL MEMBRANE
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5. MECHANISMS IN DRUG
TRANSPORT
• Transcellular transport
• Paracellular transport
• Vesicular transport
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6. TRANSCELLULAR
TRANSPORT
Passive transport
1.Passive Diffusion
2.Pore Transport
3.Ion Pair Transport
4.Facilitated Diffusion
Active Transport
1.Primary active
transport
2.Secondary active
transport
a) Symport
b) Antiport
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7. PASSIVE TRANSPORT
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8. ACTIVE TRANSPORT
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9. P-GLYCOPROTEINS
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10. PARACELLULAR
TRANSPORT
• Permeation between tight
junction of epithelial cells
• Persorption
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11. VESICULAR TRANSPORT
• Pinocytosis
• Phagocytosis
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12. SUMMARY
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13. DRUG ABSORPTION (PO)
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14. DRUG ABSORPTION THROUGH VARIOUS ROUTES
Route Absorption mechanism Drugs delivered
sublingual Passive diffusion Antianginals like nitrites and nitrates
Anti hypertensives like nifedipine
Analgesics like morphine
Bronchodilators fenoterol
Rectal Passive diffusion Aspirin, paracetamol, theophylline.
Transdermal Passive diffusion Nitroglycerine, lidocaine scopolamine, testosterone, betamethasone .
Intramuscular Passive diffusion
Endocytosis
Pore transport
Phenytion, digoxin,
Several steroids
and antibiotics
Subcutaneous Passive diffusion Insulin, heparin.
Inhalational Passive diffusion
Pore transport
Salbutamol ,cromolyn, becolmethasone .
Intranasal Passive diffusion
Pore transport
Phenylpropanolamine,
Antihistamine.
Intraocular Passive diffusion Atropine, pilocarpine, adrenaline,
Antibiotics.
Vaginal Passive diffusion Steroidal drugs and contraceptive
metronidazole
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15. FACTORS AFFECTING
DRUG ABSORPTION
Pharmaceutical
1.Particle size
2.Salt Form
3.Crystal Form
4.Hydrates
5.Nature of excipients
and adjuvants
6.Drug pKa
7.Lipophilicity
Pharmacological
1.Age
2.Gastric emptying
3.Intestinal transit time
4.Gastrointestinal pH
5.Disease state
6.Blood flow
7.Gastrointestinal
contents
8.First pass metabolism
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16. METHODS OF DELAYING
ABSORPTION
• Appropriate dosage
• Physical characteristic
• Vasoconstrictor /
tourniquet
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17. METHODS OF
FACILITATING DRUG
ABSORPTION
• Diffusion time
• Blood flow
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18. BIOAVAILABILITY
"the rate and extent to which the
active substance or active moiety is
absorbed from a pharmaceutical
form of the drug and is available at
the site of action"
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19. AREA UNDER THE CURVE
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20. PARAMETERS• Cmax
• Tmax
• AUC
• Onset of action
• Duration of action
• Intensity
• MEC
• MSC
• MTC
• Therapeutic range
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21. BIOAVAILABILITY
• Absolute
• Relative
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22. • Bioequivalence
• Chemical equivalence
• Clinical equivalence
• Therapeutic equivalence
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23. THANK YOU
Have a nice day ahead !!
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