Pharmacokinetics is the study of the movement of drugs in the body over time, including processes of absorption, distribution, metabolism and excretion (ADME). Drug absorption involves transport across biological membranes via passive diffusion, active transport or facilitated diffusion. Factors that affect drug absorption include lipid solubility, ionization, pH, area of absorption and gastrointestinal factors. The fraction of a drug that reaches systemic circulation unchanged is known as its bioavailability, while bioequivalence refers to equivalent therapeutic effects of different drug formulations. Distribution of drugs in the body is represented by the apparent volume of distribution, which is influenced by tissue permeability and plasma protein binding.

1. Dr.S.VASANTH

2. Route with high bio availability ……….?
Transport across biological membrane ….?
Absorption of drug …….?
Distribution of drug ….?
Plasma proteins ……….?

3. What is pharmacokinetics ?
ADME

5. Transport across biological memberane
Lipid

7. passive transport
Active transport
Facilitated diffusion
Symport
Antiport
Primary active transport
Secondary active transport

9.  pH of medium = pKa then drug is 50 %
unionised and 50 % ionized
 pH more than Pka medium is alkaline
 Acidic drugs ,ionization form increases and
nonionized decreases
 Basic drugs, unionized form increases and
ionized form decreases

10.  Absorption is movement of the drug from its
site of administration into the circulation
 Different routes of drug absorption ?
 Factors affecting drug absorption ?

11.  Lipid solublity /aqueous solublity
 pH/pKA value
 Gastric emptying /gut motility
 Particle size and formulation
 Food and presence of other substance /drug
 Gastrointestinal disease
 First pass metabolism

12. What is first pass metabolism ?
What is bioavailablity ?

13.  Nitrates
 Hydrocortisone
 Lignocaine
 Propanolol
 Salbutamol
 morphine

14.  Rate and extent of a drug form the dosage
form in unchanged form in the systemic
circulation
 Fraction of drug or percentage of drug
reaches systemic circulation in unchanged
form

16.  Lipid solublity /ionization /pH
 Area of absorbing surface
 Blood circulation
 Gastric motility
 Presence of food
 Disease state of git

17. First pass metabolism
Pharmaceutical factors
disintegration time
dissolution rate/time
Genetic influence's

19.  Bioequvalance?
Phenytoin
a(dilantin)
Phenytoin b
(eptoin)

20.  Apparent volume of distribution
 Volume in which drug appears to be
distributed ( apparent )if concentration
throughout the body was same to that of the
plasma
 aVd= dose administered I.V /plasma
concentration achieved

21.  1). tissue permeability of drug
a. physicochemical property – i) molecular size
ii) pKa
iii) o/w partion coefficient
b. physiological barriers
 2). Organ tissue size and perfusion rate
 3). Binding of drug to tissue components
a. with blood components
b.with extravascular tissue proteins
4). Miscellaneous factors
a. age
b.Pregnancy
d.Obesity
e.Diet
f.Disease states
g.Drug interaction


23.  Redistribution ?

24.  Plasma protein binding
 Albumin
 Alpha1 acid glycoproteins

25.  Maintance of plasma concentration
 Free and bound form measurement
 Low vd- highly bound form
 Long acting – highly bound
 Not removed by hemodialysis
 Displacement reaction
 Hypoalbuminemia ,chirosis

27.  Diazepam
 Midazolam
 Warfarin
 Imipramine
 cyclosporine

28. Bioavailablity 100% ……… ?
Bioequvalence ?.............
Volume of distribution ?
Significance of plasma protein binding ??