Abstract
A dispensing test of 10% phenytoin powders (10% DPH), which has the same bioavailability as the tablet, was investigated. Pharmaceutical characteristics including an apparent density, a dispersibility, grouping properties and an angle of repose of 10% DPH passed the criteria for dispensing from the hospital pharmacy. Next, according to clinical formulas, we designed the eight standard formulas that consisting 10% DPH with 10% phenobarbital powders, zonisamide powders, carbamazepine granules, sodium valproate granules and lactomin powders. Pharmaceutical characteristics of these standard formulas also passed the criteria required for dispensing from the hospital pharmacy. The particle size of some standard formulas showed twin-peak distribution patterns. In the mixing test of the standard formulas, all of the coefficients of variation (CV) of the phenytion content were under 5% which met the criterion (6.1%) of a guideline of dispensing (9 th Revised Edition) by Japan Pharmasist Association. CV values of net weight and phenytoin content after dividing and packing the standard formulas also met the criterion of the guideline for dispensing. The CV values of the net weight and phenytoin content in formulas exhibiting twin-peak distribution patterns in particle size were not significantly larger than those in formulas exhibiting single-peak distribution patterns of drug particles. This distribution patterns did not demonstrate a relationship to the distribution of net weight in dividing and packaging powder mixtures. The CV values of the phenytoin content showed low values (<5%) independent of the particle distribution of the formulas. These results indicate that the 10% DPH has been distributed uniformly in the mixture with the other powders and that it is an useful preparation for clinical use.
