We aimed to prepare and investigate microparticles with the varying contents of calcium gelling ion, loaded with phenytoin, a standard antiepileptic agent, in its acidic form. Two different methods of alginate-based microparticles preparation were used: with and without treatment with chitosan. Furthermore, two standard procedures, the one-stage and the two-stage, were applied. Microparticle size of 12 one-stage formulations ranged from 466 to 636 mum. Both types of formulations, chitosan-treated and nontreated, appeared to be highly loaded with the model drug (91-96%). The chitosan-coated alginate-based microparticles prepared by the one-stage procedure exhibited kinetics of phenytoin liberation comparable to a similar sustained release system that had been tested at pH 6.8, as published earlier. As the gel erosion of alginate-based microparticles should be potentiated by the higher pH (used in the present study at pH 7.4), the most favorable of 12 formulations, with the liberation half-time of about 2 hr, seemed to be eligible for further modifications. Counterintuitively, the applied two-stage procedure did not appear to beneficially affect the dissolution behavior of phenytoin when tested in two formulations, which makes further modifications necessary.

In this paper, a study exploring the stability of omeprazole in pediatric suspensions is presented. In order to determine the most suitable suspension, three different formulations were prepared and stored under refrigerated conditions and at room temperature for 30 days. Contents of omeprazole and preservatives were determined by liquid chromatographic method. Obtained results demonstrate that the vehicle consisting of: xanthan gum 0.3%, sodium bicarbonate 8%, Compound hydroxybenzoate solution APF 1% and purified water to 100% could have a significant potential in the development of a suitable omeprazole oral liquid for pediatric use. Namely, the content of omeprazole in the suspension prepared with this vehicle remained within acceptable range during the 30-day period, when stored refrigerated (2-8°C).

Traditional understanding of excipients as simple, inert and inactive ingredients of pharmaceutical preparations was changed when it became clear that they may significantly affect quality, safety and efficacy of pharmaceutical preparations. Excipients variability caused by differences in raw materials and production process may affect their performance in the final formulation. In order to manufacture/compound drug of acceptable quality it is necessary to identify those characteristics of excipients that are important for their intended function, assess mechanism and extent of their influence on the intended function, and define the acceptable range of their values. These characteristics are known as functionality-related characteristics of excipients, and the way and the extent by which excipients fulfill their intended function in final formulation is defined as their functionality. Having in mind that functionality depends on the final formulation and manufacturing/compounding process, it cannot be generalized, but it can be defined in context of certain pharmaceutical preparation, obtained by certain compounding/manufacturing process. This paper discusses definition, importance and compendial status of functionality and functionality-related characteristics of excipients, as well as functionality-related characteristics as critical quality attributes, from the perspective of QbD concept of drug development.