Question
Posted on: March 6 2013How do I have a clear gel? Ibuprofen 5% methylsalicylate 5% methylnicotinate 0.5% f.sa gel 50 g
Answer
This is not a simple formula and a good (or the best) solution is not obvious.
- if we limit ourselves to ibuprofen then there should be allight 50% alcohol in the gel to make a clear gel. I suspect that the composition of the fluphenamic acid gel, which is on the question box, can succeed.
- methylnicotinate is soluble in water but methylsalicylate does not. But perhaps the amount of alcohol is sufficient to keep the methylsalicylate in solution. If not the alcohol concentration is to be increased still.
Given that many pharmacists continue to suffer from the demand-box method to prepare a clear fluphenamic acid gel based on carbomer, it may be better to use a non-ionogenic gelvormer. The acidic nature of many Nsaids and the high alcohol concentration are game breakers. The restriction on the area of the bases, which are reimbursed by the RIZIV, still strengthens the problem. Better is perhaps to use a hydroxypropylcellulose gel and work as follows:
- Prepare 30 g HPC Gel
Weigh in the Beaker 2 G HPC (Klucel GF) and 4 G propylene glycol and mix until all HPC is moistened with propylene glycol. Add 24 g of water of approximately 75 °C and mix until a white clot is obtained free of suspension. Allow to cool, cover the gel and place overnight in the refrigerator.
- insertion of the medicinal products
Tarreer a beaker with glass rudder rod, note the tare weight weigh in this beaker 25g ethanol or isopropanol 2.5 g ibuprofen and 2.5 g methylsalicylate and 250mg methylnicotinate and dissolve. After dissolving, weigh in this beaker 25g of the pre-prepared HPC gel . Add portions of about 8g. Only after homogeneous distribution of the added amount of gel in the medicines solution can a new portion be added.
When everything is mixed place the beaker with stirrer on the balance and bring on weight (tare weight + 50) with the alcohol. Wrap the gel immediately in a tube.