GPhC Pharmaceutical Sciences & Calculations 4

Question 1

What is the molecular basis of drug tolerance?

Accepted Answer

Receptor downregulation

Answer

Tolerance often develops due to receptor downregulation — the number or sensitivity of receptors decreases with repeated drug exposure, reducing effect.

Question 2

Which type of emulsion is most suitable for intravenous administration?

Accepted Answer

Oil-in-water (O/W)

Answer

O/W emulsions are miscible with blood (which is aqueous-based), making them suitable for IV use. W/O emulsions are not compatible with blood.

Question 3

A drug with a narrow therapeutic index requires:

Accepted Answer

Therapeutic drug monitoring

Answer

Narrow therapeutic index drugs have a small margin between therapeutic and toxic doses, necessitating regular therapeutic drug monitoring (TDM) to ensure safety.

Question 4

Which process describes drug movement from blood into tissues?

Accepted Answer

Distribution

Answer

Distribution refers to the reversible transfer of a drug from the systemic circulation into tissues and organs throughout the body.

Question 5

What is the significance of a drug's pKa?

Accepted Answer

It determines the degree of ionisation at a given pH

Answer

pKa is the pH at which 50% of the drug is ionised. It helps predict ionisation state at physiological pH, influencing absorption and distribution.

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GPhC Pharmaceutical Sciences & Calculations 4