In isotonicity, which statement about Class I and Class II adjustment methods is correct?

• A. ALL statements are correct
• B. Only ONE statement is correct
• C. TWO statements are correct
• D. THREE statements are correct

Answer: (C)

Isotonicity means the solution has the same osmotic pressure as body fluids, so adjustments must reach that balance without altering the drug or causing safety issues. For Class I and Class II adjustment methods, there are typically two statements that correctly describe how these adjustments are made and why they’re chosen. The two true statements capture the essential balance: you must achieve the correct osmolarity while staying compatible with the drug and not compromising stability or safety. The other statements would either oversimplify how isotonicity is achieved or misstate constraints (for example, claiming every statement is correct or that one particular method always applies in all cases). So, the best choice is that exactly two statements are correct. When reviewing similar items, focus on which claims align with maintaining isotonicity and compatibility for the specific Class I and Class II contexts, and which do not.