Moisture sorption and desorption properties of gelatin, HPMC and pullulan hard capsules.

The moisture sorption and desorption properties of hard capsules have a great influence on the quality of capsule products. However, studies on them have rarely been reported. Herein, we studied the moisture sorption and desorption properties of three kinds of hard capsules (gelatin, hydroxypropyl methyl cellulose (HPMC) and pullulan capsules) in terms of hygroscopicity, crystallinity, thermal behaviors and so on. It is found that HPMC capsules have weaker moisture sorption ability and moisture keeping ability than pullulan or gelatin capsules with lower moisture sorption rates, equilibrium moisture contents, moisture keeping rates and higher critical relative humidity. In comparison with gelatin capsules, pullulan capsules have weaker moisture sorption ability and comparable moisture keeping ability. HPMC or pullulan capsules can more effectively protect high, moderate and low hygroscopic capsule contents (chitosan, potato starch or ethyl cellulose) from outside moisture absorption. The diffraction peaks of the moisture equilibrated gelatin, HPMC and pullulan capsules are much smaller than those of their dried ones. The dried and the moisture equilibrated gelatin, HPMC or pullulan capsules all have smooth surface morphology. HPMC or pullulan capsules can be an attractive alternative to animal gelatin capsules due to their appropriate moisture sorption and desorption properties.

Insight on the changes of cassava and potato starch granules during gelatinization.

Gelatinization is an important property of starch for biomedical applications. However, studies on the changes in starch granules in terms of morphology, swelling, amylose leaching and so on during gelatinization, which are key to uncovering the starch gelatinization process, have rarely been reported. Herein, changes of cassava and potato starch granules during gelatinization were investigated. It was found that there is a substantial difference in the granule changes during gelatinization between cassava and potato starch. Cassava starch granules remain intact with slight swelling, with approximately 8.5% amylose leaching in water for 30 min at 60 °C. In sharp contrast, potato starch granules swell very well and rapidly, losing much integrity with 51.05% amylose leaching. The gelatinization time and temperature have much greater effects on the changes of potato starch granules than cassava starch granules.

3D printing and coating to fabricate a hollow bullet-shaped implant with porous surface for controlled cytoxan release.

Intratumoral implants have aroused great interests for local chemotherapy of cancer, however, how to efficiently control drug release from implants is still a great challenge. Herein, we designed and prepared a new hollow bullet-shaped implant with porous surface by 3D printing, loaded chemotherapeutic agent cytoxan (CTX) with tetradecyl alcohol or lecithin as matrix and coated it with poly (lactic acid) to obtain a CTX implant, which has a highly tuned drug release property with a drug release time from 4 h to more than 1 month. The drug release from the implant can be easily controlled by changing pore sizes, kinds of matrices, and coating thickness.