Efficient production of nanocrystalline hydroxyapatite with desirable properties is a key focus in research on nanomaterials based on this mineral. It has been shown that, in the widely used wet synthesis method, fundamental factors such as the choice of calcium source and the type of post-reaction suspension maturation can play a crucial role. This study examines the influence of these two factors on parameters including synthesis yield, crystal size and morphology, material crystallinity and specific surface area, variations in OH group content, and the Ca/P molar ratio. The effect of these factors on drug release from tablets containing the synthesized hydroxyapatites was also evaluated. The results clearly demonstrate that calcium acetate decreases the synthesis yield of hydroxyapatite nanocrystals, particularly under dynamic maturation conditions. Moreover, this calcium source exerts the strongest influence on the drug release profile from tablets incorporating the obtained hydroxyapatite.

Vitamin C is one of the most well-known and most frequently used substances found in various pharmaceutical preparations. Patients consider it as a safe compound with multidirectional beneficial effects, while chemists have been presenting various possibilities for its determination for many years. The aim of this review is to present the current range of drugs and dietary supplements containing vitamin C available in Poland, divided into appropriate categories, taking into account doses, forms and other ingredients. The second goal is to summarize the main analytical methods for determining the content of ascorbic acid. A review of available preparations showed disproportions between a small group of drugs and a very large group of dietary supplements, which turned out to be significantly diversified in various aspects. In turn, the review of analytical methods clearly indicates the dominant share of spectroscopic ones and the fact that researchers focus primarily on improving basic, commonly known techniques.