Vliv velikosti a tvaru částic na vlastnosti léčiv
The influence of shape and size of particles (in the order of magnitude of 101–102 nm) on the physicochemical properties of API (Active Pharmaceutical Ingredient) has been the subject of intense interest in basic and applied research, especially in the last 20 years. The properties of these substances, such as solubility and dissolution rate or melting point, significantly affect both the conditions of the technological operations in the preparation of the dosage forms and the bioavailability and the effect of the drugs in the organism. The paper summarizes the results of a number of experimental works devoted to this issue and also presents simple thermodynamic concepts describing the increase of solubility or decrease of temperature and enthalpy of melting with decreasing dimensions of nanostructures. Attention is also paid to surface and interfacial energy, which is an essential variable for the quantitative description of these phenomena.