Examination of chondroitinase ABC I immobilization onto dextran-coated Fe3O4 nanoparticles and its in-vitro release.

Chondroitinase ABC I (cABC I) has received notable attention in treatment of spinal cord injuries and its application as therapeutics has been limited due to low thermal stability at physiological temperature. In this study, cABC I enzyme was immobilized on the dextran-coated Fe3O4 nanoparticles through physical adsorption to improve the thermal stability. The nanoparticles were characterized using XRD, SEM, VSM, and FTIR analyses. Response surface methodology and central composite design were employed to assess factors affecting the activity of immobilized cABC I. Experimental results showed that pH 6.3, temperature 24 °C, enzyme/support mass ratio 1.27, and incubation time 5.7 h were the optimal immobilization conditions. It was found that thermal stability of immobilized cABC I was significantly improved. In-vitro cABC I release was studied under pH 7.5 and temperature 37 °C and the results indicated that 70 % release occurred after 9 h and the release mechanism was first-order kinetic model.

Accelerated Release Testing Method and Preparation of Docetaxel Capsule Tension Ring / 中国药学杂志

OBJECTIVE: To develop the accelerated release test method of docetaxel capsule tension ring and optimize its formulation. METHODS: The effects of ethanol concentration in the medium (0%, 5%, 10%) and temperature (37 and 45 ℃) on the release rate of docetaxel capsule tension ring were investigated, and the correlation regression equation between the accelerated release rate and the long-term release was established. Then, the best prescription was screened out with the accelerated release test method. RESULTS: The drug release rate of these preparations could be increased by four times under the accelerated conditions, i.e., using pH 7.4 phosphate buffer solution containing 5% ethanol as the release medium and operating at (45±0.5)℃. The accelerated release and long-term release were fitted the best using binomial model (y=0.004 6x2+0.437 4x+9.683 7, r2=0.998 4). The preparation using PLGA5050 (60K-100K=1:1, W/W) with drug-loading of 30% released drug stably and sustainedly for 30 d, and its release behavior was consistent with Peppas equation drug release model. CONCLUSION: Accelerated release testing can be employed as a rapid screening test to facilitate the formulation optimization of docetaxel capsule tension ring. This preparation has been proven to have sustained-release characteristics, suggesting a good clinical application prospect.

Solubility and release modulation effect of sulfamerazine ternary complexes with cyclodextrins and meglumine.

This study investigated the effect on solubility and release of ternary complexes of sulfamerazine (SMR) with ß-(ßCD), methyl-(MßCD) and hydroxypropyl-ß-cyclodextrin (HPßCD) using meglumine (MEG) as the ternary component. The combination of MEG with MßCD resulted the best approach, with an increased effect (29-fold) of the aqueous solubility of SMR. The mode of inclusion was supported by 2D NMR, which indicated that real ternary complexes were formed between SMR, MEG and MßCD or HPßCD. Solid state analysis was performed using Fourier-transform infrared spectroscopy (FT IR), differential scanning calorimetry (DSC) and powder X-ray diffraction (XRD), which demonstrated that different interactions occurred among SMR, MEG and MßCD or HPßCD in the ternary lyophilized systems. The ternary complexes with ßCD and MßCD produced an additional retention effect on the release of SMR compared to the corresponding binary complexes, implying that they were clearly superior in terms of solubility and release modulation.