| 2,2,6,6-Tetramethyl-l-piperidinyloxy (TEMPO) oxidation has been applied for oxidize natural polysaccharides such as Konjac glucomannan (KGM) and starch polymer. Oxidized KGM and starch polymer were first time reported to prepare hard shell capsules and nanospheres respectively. Firstly, TEMPO-oxidized KGM (OKGM) applied as essential materials for hard shell capsules preparation. Sencondly, TEMPO-oxidized starch (OSTA) nanospheres was prepared by combining of multiple emulsifiers (Tween80 and Span80) and high-energy emulsification techniques (High-speed shearing combined with ultrasonic disruption).1. OKGM with different degree of oxidation (DO) (DO30%, DO50%, DO80%) was prepared to select optimum DO for preparation of hard capsules. FT-IR results showed that the primary alcohol groups of KGM were successfully oxidized to carboxyl groups. XRD analysis showed that TEMPO-oxidation could destroy the crystallized region of KGM. With the increasing of the oxidation degree, solubility and transparency of OKGM improved, while viscosity decreased.2. Mechanical properties of OKGM films improved with increasing degree of oxidation; It can be observed from the measurement results that the contact Angle decreased with the increasing of the oxidation degree, so the hydrophilic of OKGM capsules increased. The improvement of the hydrophilic is conducive to the collapse of the OKGM capsule3. The DO80% and DO30% OKGM were chosen to prepare hollow hard capsule. Stearic acid erythromycin as a model drug was used in vitro drug dissolution profile of OKGM capsule. The shell rupture time of DO30% OKGM is 45-60min,80% of the drugs were released within 90-120min; For DO80% capsule shell rupture time is about 5-10 min, and 80% of the drugs were released within 30-45 min. Thus DO80% OKGM was compatible with the test of Chinese Pharmacopoeia, and was optimum for preparation of hard capsules.4. DO90% OSTA was developed to prepare nanospheres by using Fe3+ as the cross-linking agent. The Span80 and Tween80 were mixed as emulsifier while the liquid paraffin as oil phase. High-speed shearing combined with ultrasonic disruption was used to decrease the size of emulsion. The size of the OKGM nanospheres was in about 200 nm to 300 nm.5. Electrostatic adsorption of positively charged poly electrolyte on the negatively charged surface of nanospheres increased the stability of nanospheres under pH 3 and pH 7, and the optimal adsorption quantity was determined. When the nanospheres were used as the carrier of the doxorubicin hydrochloride (DOX·HCl), it can be observed that the embedding rate was determined by the doxorubicin hydrochloride content and the polyelectrolyte adsorption amount. With the increasing addition quantity of the doxorubicin hydrochloride, the embedding rate of the doxorubicin hydrochloride is increased; with the increasing amount of the polyelectrolyte adsorbed, the embedding rate of the doxorubicin hydrochloride is decreased. |
