The document defines key concepts in biopharmaceutics including absorption, bioavailability, drug disposition, and elimination. It also defines related terms like pharmacokinetics, pharmacodynamics, and various types of equivalence. The concepts are explained with examples and factors affecting absorption via different routes of administration are discussed. The document also describes the four phases of drug administration and therapy: the pharmaceutical, pharmacokinetic, pharmacodynamic, and therapeutic phases.

1. Definitions and Concepts
Dr. Basavaraj K. Nanjwade M. Pharm., Ph. D
Department of Pharmaceutics
Faculty of Pharmacy
Omer Al-Mukhtar University
Tobruk, Libya.
E-mail: nanjwadebk@gmail.com
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3. Definitions
• Biopharmaceutics
• Absorption
• Bioavailability
• Drug disposition
• Drug distribution.
• Elimination
a. Biotransformation(Metabolism)
b. Excretion
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4. Definitions
• Pharmacokinetics
• Clinical pharmacokinetics
• Pharmacodynamics
• Equivalence.
• Bioequivalence.
• Pharmaceutical Equivalence.
• Pharmaceutical Alternatives.
• Therapeutic Equivalence.
• Bio-Inequivalence.
• Bioequivalences studies.
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5. Biopharmaceutics
Biopharmaceutics is defined as the study of
factors influencing the rate and amount of
drug that reaches the systemic circulation and
the use of this information to optimise the
therapeutic efficacy of drug products.
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6. Biopharmaceutics
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7. Absorption
Definition :
• The process of movement of drug from its site
of administration to the systemic circulation is
called as absorption.
• The process of movement of unchanged drug
from the site of administration to systemic
circulation.
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8. Absorption
 There always exist a correlation between the plasma
concentration of a drug & the therapeutic response
& thus, absorption can also be defined as the process
of movement of unchanged drug from the site of
administration to the site of measurement.
i.e., plasma.
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9. G. I. T.
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10. Buccal
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11. Sublingual
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12. Skin (Dermal)
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13. Skin (Dermal)
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14. Skin (Dermal)
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15. Eye (Ophthalmic)
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16. Nasal (Nose)
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17. Lung (Respiratory)
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18. G. I. T.
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19. Bioavailability
• Bioavailability is defined as the rate and extent
(amount) of drug absorption.
• The relative amount of an administration dose of a
particular drug that reaches the systemic circulation
intact and the rate at which this occurs is known as
the bioavailability.
• The fraction of an administration dose of the drug
that reaches the systemic circulation in the
unchanged form is known as the bioavailable dose.
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20. Absolute Bioavailability
 Absolute Bioavailability :-
If the systemic availability of a drug
administered orally is determined by doing its
comparison with I.V. administration, it is
known as absolute bioavailability.
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21. Relative Bioavailability
 Relative Bioavailability :-
If the systemic availability of a drug
administered orally is determined by doing its
comparison with that of an oral standard of
the same drug, it is known as a relative
bioavailability.
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22. Drug disposition
• Any alternative in the drug’s bioavailability is
reflected in its pharmacological effects. Other
processes that play a role in the therapeutic
activity of a drug are distribution and
elimination. Together, they are known as drug
disposition.
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23. Drug distribution
• The movement of drug between one
compartment and the other (general blood
and the extra-vascular tissues) is referred to
as drug distribution.
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24. Elimination
• Elimination is defined as the process that
tends to remove the drug from the body and
terminate its action.
• Biotransformation(Metabolism): Which usually
inactivevates the drug.
• Excretion:Which is responsible for the exit of
drug/metabolites from the body.
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25. Biotransformation
(Metabolism)
• Biotransformation(Metabolism):Which usually
inactivates the drug.
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26. Excretion
• Which is responsible for the exit of
drug/metabolites from the body.
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27. Pharmacokinetics
• Pharmacokinetics is defined as the study of time
course of drug ADME and their relationship with its
therapeutics and toxic effects of the drug.
• Simply speaking, pharmacokinetics is the kinetics of
ADME or KADME.
• Pharmacokinetic is a study of what the body does to
the drug, whereas.
• Pharmacokinetics relates changes in concentration of
drug within the body with time after its
administration, whereas.
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28. Clinical pharmacokinetics
• The use of pharmacokinetic principles in
optimising the drug dosage to suit individual
patient needs and achieving maximum
therapeutic utility is called as clinical
pharmacokinetics.
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29. Pharmacodynamics
• Pharmacodynamic is a study of what the drug
does to the body.
• Pharmacorelates response to concentration of
drug in the body.
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30. Equivalence
• This term compares the drug products to the
characters or functions to the set of
standards.
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31. Bioequivalence
• It refers that the drug substance in two or
more identical dosage forms, reaches
systemic circulation at the same rate and to
the same relative extent. i.e. their plasma
concentration time profiles will be identical
without significant statistical differences.
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32. Pharmaceutical Equivalence
• Drug products in identical dosage forms that
contains the same active ingredients, use the
same route of administration, and are
identical in strength or concentration, quality,
purity, content uniformity, however they may
differ in containing excipients.
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33. Pharmaceutical Alternatives
• Drug products that contain the same
therapeutic moiety but as different salt, ester
or complex. For e. g. tetracycline phosphate or
tetracycline hydrochloride equivalent to 250
mg tetracycline.
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34. Therapeutic Equivalence
• It indicate that two or more drug products
that contain same therapeutically active
ingredients, elicit identical pharmacologic
effect and can control the disease to the same
extent.
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35. Bio-Inequivalence
• When statistically significant differences are
observed in the bioavailability of two or more
drug products called as bio-inequivalences.
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36. Bioequivalences Studies
Bioequivalence studies are performed by
comparing the bioavailability of, to-be-marketed
Generic product with that of the Brand product.
Pharmacokinetic studies are conducted whereby each
of the preparations are administered in a cross-over
study to volunteer subjects, generally healthy
individuals but occasionally in patients.
Serum/Plasma samples are obtained at regular
intervals and assayed for parent drug (or occasionally
metabolite) concentration.
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37. Drug Administration and Therapy
1. The Pharmaceutical Phase.
2. The Pharmacokinetic Phase.
3. The Pharmacodynamic Phase.
4. The Therapeutic Phase.
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38. The pharmaceutical Phase
• It is concerned with-
a.Physicochemical properties of the drug, and
b.Design and manufacturing of an effective drug
product for administration by a suitable route.
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39. The Pharmacokinetic Phase
• It is concerned with the ADME of drugs as
elicited by the plasma drug concentration-
time profile and its relationship with the dose,
dosage form and dosing frequency and route
of administration. In short, it is the sum of all
the processes inflicted by the body on the
drug.
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40. The Pharmacodynamic Phase
• It is concerned with the bio-chemical and
physiological effects of the drug and its
mechanism of action. It is characterized by the
concentration of drug at the site of action and
its relation to the magnitude of effects
observed.
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41. The Therapeutic Phase
• It is concerned with the translation of
pharmacological effect into clinical benefit.
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42. Concept of Bioavailability
• Be completely released from the dosage form.
• Be fully dissolved in the gastrointestinal fluids.
• Be stable in solution in the gastrointestinal
fluids.
• Pass through the gastrointestinal barrier into
the mesenteric circulation without being
metabolized.
• Pass through the liver into the systemic
circulation unchanged form.
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43. Concept of Biopharmaceutics
• In the same type of dosage form by different routes of
administration, e.g. an aqueous solution of a given drug
administered by the oral and intramuscular routes.
• By the same routes of administration but different types
of dosage form, e.g. a tablet, a hard gelatin capsule and
an aqueous suspension administered by the peroral
route.
• In the same type of dosage form by the same route of
administration but with different formulations of the
dosage form, e.g. different formulations of an oral
aqueous suspension.
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44. Poor biopharmaceutical properties
• Poor and variable bioavailability.
• Difficulties in toxicological evaluation.
• Difficulties with bioequivalence of
formulations.
• Multi-daily dosing.
• The requirement for a non-conventional
delivery system.
• Long and costly development times.
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45. References
1. “Biopharmaceutics & pharmacokinetics”, D.M.
Brahmankar & Sunil B. Jaiswal, Vallabh prakashan.
2. “Text book of Biopharmaceutics &pharmacokinetics”,
Dr. Shobharani R. Hiramath.
3. “Applied Biopharmaceutics & pharmacokinetics”,
Leon Shargel & Andrew B.C.
4. www.google.com
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E-mail: nanjwadebk@gmail.com