New Aspects in the Formulation of Drugs Based on Three Case Studies.

The improvement of pharmaceutical dosage forms, such as tablets, towards drug delivery control and cost efficiency is of great importance in formulation technologies. Here, three examples: in situ coating, freeze casting and protein-based biocomposites are presented that address the above mentioned issues and contribute to further developments in formulation technologies. The in situ coating increases the economic efficiency by saving process steps in comparison to a conventional tableting process and provides a crystalline coating for a tailorable drug delivery rate. The freeze casting allows the control over the surface area of a drug delivery system (DDS) by providing different numbers and sizes of pores, which in conjunction with adequate additives offer an efficient instrument for drug delivery control, especially by accelerating the dissolution effect. Protein-based biocomposites are attractive materials for biomedical and pharmaceutical applications that can be applied as a polymeric DDS. They inherently combine degradability in vivo and in vitro, show a good biocompatibility, offer sites of adhesion for cells and may additionally be used to release embedded bioactive molecules. Here, a new approach regarding the incorporation of crystalline active pharmaceutical ingredients (API) into a protein matrix in one process step is presented. All three presented techniques mark decisive progress towards tailor-made drug delivery systems with respect to function, economic efficiency and the generation of additional values.

Kinetic study on hemipenta hydrate risedronate monosodium in batch crystallization by cooling mode.

The crystallization kinetics of hemipenta hydrate risedronate monosodium (RS) were investigated in cooling mode. The solubility, induction time, mechanism of nucleation and crystal growth in the crystallization of hemipenta hydrate RS in water as a solvent were determined by the in situ measurement using focused beam reflectance measurement (FBRM). The relationship between induction time and the supersaturation was obtained for understanding mechanism of nucleation. The nucleation mechanism including homogeneous and heterogeneous nucleation was grasped with respect to the supersaturation. From the results of nucleation experiments, the interfacial tension of hemipenta hydrate RS was determined. Furthermore, the kinetics of crystal growth was also obtained. The crystal growth of hemipenta hydrate RS was controlled by the combination of one and two-dimensional growth mechanisms.