ABSTRACT
Microwaves can be directly transformed into heat inside materials because of their ability of penetrating into any substance. The degree that materials are heated depends on their dielectric properties. Materials with high dielectric loss are more easily to reach a resonant state by microwaves field, then microwaves can be absorbed efficiently. Microwave irradiation technique with the unique heating mechanisms could induce drug-polymer interaction and change the properties of dissolution. Many benefits such as improving product quality, increasing energy efficiency and reducing times can be obtained by microwaves. This paper summarized characteristics of the microwave irradiation technique, new preparation techniques and formulation process in pharmaceutical industry by microwave irradiation technology. The microwave technology provides a new clue for heating and drying in the field of pharmaceutics.
ABSTRACT
Converting two poorly water-soluble crystalline drugs to co-amorphous drug systems by ball milling, quench-cooling, or cryo-milling method can improve stability of the drug, enhance dissolution rates, and reduce adverse reactions of the single drug. Co-amorphous system has been used to solve problems of co-administration of medicines. Formation and intermolecular interactions of co-amorphous drug systems may be verified by differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), Raman spectroscopy (RS) and Fourier transform infrared spectroscopy (FT-IR). Stability of co-amorphous drug systems is influenced by their glass transition temperature (Tg) and intermolecular interactions. The theoretical Tg values and the interaction parameter x are calculated by Gordon-Taylor equation and the Flory-Huggins equation, respectively. Thus, co-amorphous drug systems are analyzed theoretically at molecular level. Co-amorphous drug systems provide a new sight for the co-administration of medicines.