Question
Posted on: March 6 2013We get regular demand around following magistal preparation: Boric acid 2 G alcohol 70% ad 20 g
How to solve boric acid? In theory, boric acid is soluble 1 in 18 in water and alcohol. Shifting the proportions alcohol and water offers no solution here, I suspect. Micromedex describes that a 4% solution of boric acid in 25% alcohol is effective for treating otitis externa. So does it seem possible to reduce the concentration of boric acid in this solution?
Answer
Different formulas of droplets with boric acid circulate:
- Boric acid 800 mg, water up to 20 ml: no problem, solubility not exceeded
- boric acid 2 g, alcohol 10% in water up to 20 ml: solubility exceeded, not all boric acid dissolves
- Boric acid 2 g, alcohol 70% in water up to 20 ml: solubility exceeded, not all boric acid dissolves on
- boric acid 800 mg, alcohol 25% in water up to 20 ml (formula from Micromedex): Solubility not exceeded
- Regulation 3 is what I would prescribe; Pati ë NT should be "shaking before use"
- these ear drops are only prescribed in persistent cases of otitis externa, infected Radical cavities, fungal infection, and the like, if the modern droplets have failed or have already been used for too long.