the physiochemical properties of drugs

Question 1

some examples of the various physiochemical properties of drugs

Answer 1

Solubility
Partition Coefficient
LogP
Ionization
Hydrogen Bonding
Chelation
Surface activity
Isosterism

Question 2

chelation

Answer 2

refers to the formation of a complex between a metal ion and a drug molecule

Question 3

chelating agent

Answer 3

aka chelator or ligand, is a substance that has multiple sites capable of binding to a metal ion, creating a stable complex.

Question 4

epicutaneous drugs

Answer 4

drugs applied onto the skin

Question 5

factors that affect drug absorption

Answer 5

Concentration of the drug
Route of administration
Solubility of the drug
Dissolution rate for solid dosage form

Question 6

the main processes by which a drug molecule crosses the natural barriers(e.g cell membranes )

Answer 6

Simple diffusion◦ Facilitated diffusion◦ Pore transport◦ Diffusion of the ion across the membrane◦ Active transport◦ phagocytosis

Question 7

is the blood always distributed evenly around the body?

Answer 7

no, it is evenly distributed throughout the blood supply, and since certain areas of the body have larger blood supllies than others, the distribution is proportional to this.

Question 8

do different drugs penetrate different tissues at the same speed?
give a reason for your answer

Answer 8

no, because this is dependent on the drugs ability to cross the membranes of the particular tissues

Question 9

what are some factors that drug distribution into tissues might be dependent on

Answer 9

permeability
age of person
weight…etc

Question 10

drug metabolism

Answer 10

chemical alteration of the drug by the body

Question 11

prodrugs

Answer 11

drugs that are administered in an inactive form and metabolized into the active form

Question 12

can metabolites have the same therapeutic effect or toxicity as the original drug

Answer 12

they may have similar toxicities and therapeutic effects

Question 13

instead of being excreted after being metabolised, what could happen to the drug metabolites ?

Answer 13

they could be metabolised further and then excreted

Question 14

the termination of the effects of a drug is caused by?

Answer 14

biotransformation
excretion of the metabolites/drug

Question 15

during drug metabolism, a significant portion of the drug is metabolised to……………………. chemical by the hepatic enzyme

Answer 15

inactive

Question 16

name some known storage sites for drugs in the body

Answer 16

Plasma proteins, certain tissues, neutral fat, bone and transcelluar fluids(gastro intestinal tract)

Question 17

name some factors on which the aqueous solubility of a drug depends on

Answer 17

Buffer & Ionic strength
Polymorphism & Purity of the sample
pH
Super saturation
Thermodynamic Vs Kinetic solubility