1. PREPARED BY:- GUIDE BY:-
PATEL BHAVIN Mr. V.M.PATEL
M.PHARM SEM-1
DEPARTMENT OF QUALITY ASSURANCE
A.P.M.C COLLEGE OF PHARMACEUTICAL SCIENCE &
RESEARCH,
HIMMATNAGAR.

2.  Design and development of new drugs with greatly improved
therapeutic effectiveness and fewer or no toxic effects
 Design and development of an optimum formulation for better
use of the drug
 Design and development of controlled/targeted release
formulation
 Select the appropriate route for drug administration

3.  Select the right drug for a particular illness
 Predict and explain drug-food and drug-drug interactions
 Design an appropriate multiple dosage regimen
 Therapeutic drug monitoring in individual patients
 Dosage adjustments in situations of altered physiology
and drug interactions

4.  To understand process of absorption, distribution and
elimination of drug , which affects onset and intensity of
biological response.
 To access plasma drug concentration response to given dose
which is now considered as more appropriate parameter then
intrinsic pharmacological activity .
 In design and utilization of in vitro model system that can
evaluate dissolution characteristics of new compound
formulated as new drug formulations and establish meaningful
in vivo in vitro correlation ship.
 In design and development of new drug and their appropriate
dosage regimen.
 In safe and effective management of patients by improving
drug therapy.

5.  To understand concept of bioavailability which has been used to
evaluate and monitor in vivo performance of new dosage forms
and generic formulations.
 To carry out bioavailability and bioequivalence studies.
 We can use pharmacokinetic principles in the development of
various NDDS.
e.g. The drug with short half life about 2-6 h can be
formulated as controlled release drugs by using polymers .
The lower bioavailability of the drugs can be increased by
using several components like β – cyclodextrin
 List of drug carriers in NDDS :-
Nanosomes, Liposomes, Niosomes, Proniosomes, vesicular
drug delivery system, Cubisomes, Aquasomes,
Pharmacosomes,Nanoparticle, Nanosphere, Microsphere,
Microparticle, Transferosomes, Micro emulsion,
Nanosuspension, Dendrimers, Micelles, Dendrosomes.

6.  Many drugs are investigated now a days and the estimation of
their activity and pharmacokinetics properties are important
for knowing the ADME of that particular drug . By
understanding the mechanism of disease the drug design is
done .The drug design is based on the mechanism of the
particular disease. Some newly discovered drugs that shows
very high activity in in vitro but in in vivo that drug not shows
high activity or show high toxic activity. This toxic nature of
the drug in in vivo can be explained by studying the
pharmacokinetics properties that is the formation of reactive
metabolites.
 Some newly invented drugs showing undesirable pk properties
such as too long or too short t 1/2 , poor absorption and
extensive first pass metabolism .

7.  Two physicochemical factors that effect the both extent and
rate of absorption are lipophilicity and solubility .
 Increase in the lipophilic nature of drug results in increased in
oral absorption .
e.g. Biophosphonates drug with poor lipophilicity will be
poorly absorbed after oral administration . Absorption of
the barbiturates compounds increased with increasing
lipophilicity.
 Higher the lipophilicity of a drug the higher its permeability
and the greater its metabolic clearance due to first pass effect.

8.  Solubility is also an important determinant in drug absorption.
e.g. HIV protease inhibitors are basically lipophilic and
poorly soluble resulting in poor bioavailability. The
solubility of the HIV protease inhibitors can increased
by incorporating a basic amine in to the back bone of this
series.
 Pro drugs are developed to improve oral absorption .
e.g. Pivampicillin, Becampicillin are the pro drugs of
Ampicillin.

9.  Lipophilicity of the drug affects the distribution. Higher the
lipophilicity of a drug the stronger its binding to protein & the
greater its distribution.
e.g. Thiopental & polychlorinated insecticides. These drugs
are highly distributed and accumulate in adipose
tissue.

10.  Determination of metabolic pathways
 Study of drug metabolic pathways are useful for determining
the nature of metabolites and used for toxicity studies.
 Isolation & cultured hepatocytes are also often used as in-vitro
models for identifying metabolic pathways of drug.
e.g. The major metabolic pathways of indinavir in human have
been identified as,
o Glucaronidation at the pyridine nitrogen to yield a quaternary
ammonium conjugate
o Pyridine n-oxidation
o Para –hydroxylation of the phenyl methyl group
o 3-hydroxylation of the chain
o N- depyridomethylation

11.  Administration of a drug with a short half life requires frequent
dosing and often results in patient incompliance. Half life
determined by distribution & elimination. The prolongation of
half life can be achieved by increasing the volume of
distribution & decreasing the clearance. Latter appear to be
easier i.e. to modify the chemical structure to slow down a drug
clearance than to increase its volume of distribution.
 e.g. The addition of an alkyl amine side chain linked to the
dihydropyridine 2-methyl group yield amlodipine with a lower
clearance which has an improved oral bioavailability and
plasma half life without loss of antihypertensive activity.

12. Biopharmaceutics & clinical pharmacokinetics by Milo
Gilbaldi 4th edition , Philadelphia lea & Febiger 1991
Biopharmaceutics & pharmacokinetics a treatise D.M.
Brahmankar & Sunil b. Jaiswal ,Vallabh Prakashan
Pitampura, Delhi
Text book of Biopharmaceutics & pharmacokinetics by
Dr.shobha rani R.Hiremath, prism books Pvt
Ltd,bangalore,2002