PHARMACY REVIEWER NOTES (BBYN)
Module 1 : Introduction to PMOC
Medicinal Chemistry
- Branch of chemistry involved in identification,
design, synthesis, and development of biologically
active compounds ( chemical compounds that
targets our biological compounds producing effects :
Alter Physiological action in the body )
- An interdisciplinary science : Organic Chemistry,
Biochemistry, Computational Chemistry,
Pharmacology, Pharmacognosy, Molecular biology,
Physical Chemistry
- 14, 315 drugs
Drugs:
- Are low MW chemical substances that interact with
macromolecular targets ( CHAINS - Proteins, Nucleic
Acids ) in the body to produce effect.
- DRUG affects the BODY ( Pharmacodynamics ),
BODY affects the DRUGS ( Pharmacokinetics )
1. Pharmacodynamics
a. What the drug does to the body
i. GOAL: Design a drug that will interact
as powerfully and selectively as
possible for the target
b. ENDOGENOUS COMPOUNDS ( Natural)
i. body’s own natural chemicals (
Hormones AUtacoids, NT)
c. EXOGENOUS COMPOUNDS
i. foreign substances (XENOBIOTICS)
DRUGS
d. Drug -> Target -> Response/Effect (
Therapeutic, Subtherapeutic - less powerful,
and toxic - less selective)
2. Pharmacokinetics ( destiny of the drug)
a. What the body does to the drug
b. Design the drug so that it is capable of
reaching that target
c. ADME ( Absorption, Distribution, Metabolism,
Excretion)
Liberation ( Drug release) API - Dissolution
- When the conventional dosage forms are
administered orally or topically , the active drug in the
dosage form is immediately released and absorbed
into the systemic circulation .
- Diffusion is the most common mechanism
controlling drug release.
Drug Absorption
- Absorbed : LUNA
- Lipophilic
- Unionized
- Non- polar
- Excreted : HIPE
- Hydrophilic
- Ionized
- Polar
- Drugs
- Weak Electrolyte
- Weak Acids
- Weak Basics
● Oral Administration - GIT
- The most common and popular route
- Stomach = Absorption environment ( Acidic)
*pH 1.5-2 fed state; pH 2-6 fasting state
- Small Intestine ( Basic) * main site of
absorption
- High surface Area ( Villi or Microvilli)
- High perfusion -> high blood supply
➔ Predicting the Degree of Ionization at a given pH
◆ Acidic drug + Acidic medium = UNIONIZED
(ABS)
◆ Basic drug + Basic medium = UNIONIZED
(ABS)
◆ Acidic drug + Basic medium = IONIZED (EX)
◆ Basic drug + Acidic medium = IONIZED (EX)
◆ At what medium are acidic drugs readily
absorbed?
● More absorbed > UNIONIZED = A + A
◆ At what medium are acidic drugs readily
excreted?
● More excreted > IONIZED = A + B
● Parenteral Administration
- Direct to Systemic Circulation
- Rapidly distributed
- IV, IM, SC, Intraspinal, Intracerebral
● BLOOD BRAIN BARRIER -> Lipophilic
- Protects the brain from exposure to
chemicals and metabolites, due to the
presence of tightly joined epithelial cells
lining the cerebral capillaries
Drug Distribution
- Drug movement from the systemic circulation going
to different organs and tissues
- Blood Flow
- Perfusion : High P = High A
- Delivery of drug to the tissue is controlled by
the specific blood flow to a given tissue
- Delivery to target site
Drug Metabolism
● BIOTRANSFORMATION
○ Chemical Conversion -> Inactive form ( HIPE
-> e), Chemical -> Enzymes, Enzymes -> HIgh
Concentration = Liver Main
- All substances in the circulatory system,
including drugs, metabolites, and nutrients,
will pass through the liver .
- Most molecules absorbed from the GIT enter
the portal vein and are initially transported to
the liver.
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