Is it possible to prepare a clear gel containing theophylline?

A completely clear gel is not possible; a very lightly cloudy white gel, which penetrates well into the skin. After all, theophylline is a weakly acidic compound (pKa = 8.6) with limited water solubility. Using a fairly simple and classic formula it can be calculated that for a 4% solution a pH of 9.25 is required to prepare a solution. This is a fairly high pH and perhaps not appropriate for a dermatological preparation. Given that Carbopol has stronger acidic properties as theophylline, this product will be released back from a solution of theophyl line, obtained by reaction of Theophyllline with BV. Naoh. This also applies if we leave aminophylline, the water soluble ethylenediamine salt of theophylline. Given that theophylline itself is very little soluble in both ethanol and isopropanol, the ability to prepare a clear gel is greatly reduced. The experience showed that the use of aminophylline led to the simplest method of preparation. Tarreer a barrel together with a spatula and prepare a carbopol gel according to the formula of the future therapeutic Magisteric formulary (see Galenic formulary by R. Kinget). However, only 250 ml of water is added. Add to this gel the aminophylline, equivalent to 12 g theophylline, under good blending, gradually and eventually the remaining ingredients. Place barrel with spatula on the balance and bring on weight. Mix the obtained gel for a few minutes and fill it in a tube. PS: Theophylline (1 part) can also be put in solution with Nabenzate (1.2 parts) or theophylline can also be used after glycinate, of course if conversion.