Which method is an example of Class I isotonicity adjustment?

• A. White Vincent Method
• B. NaCl Equivalent Method
• C. Liso Method
• D. Osmolarity Adjustment

Answer: (A)

Isotonicity adjustment aims to make a solution have the same osmotic effect as body fluids, so cells aren’t harmed or irritated by the preparation. Class I methods are direct, practical ways to achieve that isotonicity, typically by adding a saline-based agent and using straightforward measurements to reach the target osmolality.

The White-Vincent method is the classic direct approach: it brings a solution to isotonicity by empirically adding a defined amount of saline and comparing to a standard isotonic solution. This direct, hands-on adjustment to reach the desired osmotic balance is what places it squarely in Class I.

The other methods are more indirect or calculation-based ways to assess tonicity (for example, converting a solute’s effect to NaCl equivalents or using a broader osmolarity adjustment concept). They don’t exemplify the immediate, in-formulation adjustment that characterizes Class I.