Question
Posted on: March 19 2013How do I avoid precipitation of salicylic acid?
This preparation shows needle-shaped precipitation after 24 hours. How can I avoid this?
R/Salicylic Acid 0.3 g, vanillin 10mg, spiritus 5 ml, liquid sorbitol 20ml, AQUA AD 100ml
Answer
take 10 ml of the spirit and dissolve it on salicylic acid and vanillin; add sorbitol; All in one size glass;
dilute gently with water and observe whether it is cloudy;
When clouding occurs add 5 ml of spiritus to dissolve cloudy; additional 5 ml if necessary and dilute further with water and observe or precipitate; if precipitation, add 5 ml of spiritus etc up to 100 ml;
record the amount of spiritus, which is in total in the preparation and correct the original formula.