How Phenytoine process 1 to 3% in a local ointment? Formula?

Introduction This problem was already dealt with by the NRF, which was not the ideal solution. In the "Rezepturhinweise", a sterile phenytoin gel is proposed on the basis of Hydroxyethyl Cellulose (Natrosol). But this gel is autoclaved in toto. This treatment leads, as could be foreseen, to increase the particle size and sagging of the suspended powder. After all, fenytoine is only limited soluble in water. A thermoanalytical study has shown that by heating 1 you at 150 °C the fenytoine does not undergo any changes (see data obtained by Prof. G. Van den Mooter ). This determination allows aseptic preparation.

Preparation method (quantities foreseen for 100 g 3% gel) Bring in a small tarred jar 2.5 g Natrosol (high viscosity), glycerin 10 g, NaCl 0.9 g and purified water until 100 g. Mix and close the jar. Sterilize the whole in the autoclave for 15 minutes at 120 °C. Sterilize a mortar with pestle and a few spatulas as well as an ointment tube. This material is pre-packaged separately. Rub in a mortar 4 G fenytoine into very fine powder and weigh 3 g on a watch scale. It is covered with aluminium foil for 1 hour sterilized at 150 °C. After the sterilisation, drying and cooling of the various sterilized cases, the total mass of the jar with the gel is determined and noted first. Then the 3 G phenytoin powder is transferred into the sterilized mortar and rubbed with a small part of the sterilized gel. Then it is gradually supplemented with gel until a total mass of 97 g from the jar was taken. This quantity is determined by reweighting. In principle, this mixing must be carried out in an aseptic manner in a LAF cabinet.