1. What is the Alligation Method?

The alligation method is a mathematical technique used in pharmacy to calculate the relative proportions of two solutions of different concentrations needed to prepare a solution of intermediate concentration.

2. How Does the Calculator Work?

The calculator uses the alligation method:

Where:

• \( C_{\text{high}} \) — Higher concentration (%)
• \( C_{\text{low}} \) — Lower concentration (%)
• \( C_{\text{desired}} \) — Desired concentration (%)
• Parts — Dimensionless ratio of components

Explanation: The method calculates the proportional parts needed from each stock solution to achieve the desired concentration.

3. Importance of Alligation in Pharmacy

Details: Alligation is essential for accurately preparing compounded medications, IV solutions, and other pharmaceutical preparations requiring specific concentrations.

4. Using the Calculator

Tips: Enter all concentrations as percentages. The desired concentration must be between the high and low concentrations. Results show the ratio of parts needed from each stock solution.

5. Frequently Asked Questions (FAQ)

Q1: What if my desired concentration is outside the range?
A: The alligation method only works for intermediate concentrations. For concentrations outside your stock solutions' range, you'll need different stock solutions.

Q2: How do I convert parts to actual volumes?
A: Divide each part by the total parts to get the fraction, then multiply by your desired total volume.

Q3: Can this be used for solid mixtures?
A: Yes, the method works for both liquid solutions and solid mixtures when working with concentrations by weight.

Q4: What about more than two components?
A: The method can be extended to multiple components through serial alligation.

Q5: How precise is this method?
A: It's mathematically exact for ideal solutions. In practice, account for density changes and non-ideal mixing when working with real solutions.