Question

An antibiotic dissolves completely in 250 mL of aqueous solution at pH range 1–6.8 and 37°C, and after dissolution, it shows 85% absorption in the body. Based on the Biopharmaceutics Classification System (BCS), in which class does this drug belong?

• A. Class I
• B. Class II
• C. Class III
• D. Class IV

Hint:

BCS classification aids in predicting drug absorption and guiding formulation strategies. Class III drugs often require permeability enhancement techniques.

Answer 1

The Correct Option is C

The Biopharmaceutics Classification System (BCS) categorizes drugs based on their solubility and intestinal permeability:
- Class I: High solubility, high permeability
- Class II: Low solubility, high permeability
- Class III: High solubility, low permeability
- Class IV: Low solubility, low permeability
Key points from the question:
- The drug dissolves completely in 250 mL aqueous solution over a pH range 1–6.8 at 37°C, indicating high solubility.
- The drug shows only 85% absorption, which suggests low permeability (high permeability is generally $>$85% absorbed, but borderline values and context suggest moderate to low permeability).
Thus, the drug fits the profile of Class III, which is characterized by high solubility but low permeability.