Influence of solid dispersion technique combination on dissolution of tanshinone IIA / 中国中药杂志

<p><b>OBJECTIVE</b>To compare the influence on the dissolution of tanshinone IIA (TS IIA) solid dispersions in complex carriers and single, which used in preparation of TS IIA solid dispersions, and further enhance the dissolution of TS IIA.</p><p><b>METHOD</b>The TS IIA solid dispersions were prepared by solvent technique with polyvinylpyrrolidone K30 (PVPK30), poloxamer188 (F68) and combination of PVPK30 and F68 as carriers, respectively. The physical characteristics of TS IIA solid dispersions was studied using differential scanning calorimetry (DSC). Dissolution rates were studied using small cup method (CHP XC III). The solubility of TS IIA with the solid dispersions and pure drug form were determined by HPLC method.</p><p><b>RESULT</b>The DSC analysis suggested that TS IIA was dispersed as an amorphous form in the combination of PVPK30 and F68. Dissolution profile of the prepared solid dispersions could be described by Weibull equation (R>0.99). For tested three carries, Td value (calculated time to 63.2% of total drug release according to Weibull equation) were (90.40 +/- 2.82) min, (204.5 +/- 8.20) min and (25.83 +/- 0.13) min, respectively. The PVPK30/F68-TS IIA solid dispersion resulted in a significant increase of TS IIA solubility compared with prepared PVPK30-TS IIA and F68-TS IIA solid dispersions (P<0.01).</p><p><b>CONCLUSION</b>As compared to single use of PVPK30 or F68, the combination of PVPK30 and F68 improve the dissolution rate and solubility of TS IIA significantly in the prepared solid dispersions (P<0.01). The application of complex carriers in solid dispersion technology should be paid more attention to improvement of poorly soluble drugs dissolution in the future.</p>

Study on the preparation of folate-conjugated albumin nanoparticles / 生物医学工程学杂志

Bovine serum albumin nanoparticles(BSANP) were prepared by desolvation method. The activated folic acid (N-hydroxysuccinimide ester of folic acid) was conjuated to the surface of BSANP via the amino groups. Then the folate-conjugated BSANPs (folate-BSANP) were purified with Sephadex G-50 column and completely separated from unreacted folic acid. After chymotryptic hydrolysis, the extent of folate conjugation on the BSANP was determined by quantitative ultraviolet(UV) spectrophotometric analysis. It was found that the spectrum of trypsin digest of folate-conjugate BSANP is basically identical with that of folate, thus indicating folate is successfully expressed on the surface of BSANP. The folate-BSANP was averagely 66 nm in diameter and was spherical in shape. Folate-conjugated BSANP was achieved, which represents a potential new drug carrier for tumor cell-selective targeting.

Preparation of valaciclovir loaded bovine serum albumin nanoparticles surface-modified with glycyrrhizin and its characteristics of targeting to liver / 生物医学工程学杂志

The valaciclovir was used as the model drug, the bovine serum albumin nanoparticles (BSA-NP) were prepared by desolvation process. Glycyrrhizin (GL) was oxidized by sodium periodate to be conjugated to surface reactive amino groups (SRAG) of the VACV-BSA-NP. Gel filtration method combined with HPLC method verified that GL was covalent coupling to the surface of VACV-BSA-NP with mean 9 GL residues per albumin molecule. The mean diameter of the VACV-BSA-NP-GL was 268 +/- 23 nm, the drug loading was 1.35%, and embedding ratio was 68.76%. The characteristics of release in vitro were in accord with two-phase kinetics. The uptake amount of VACV-BSA-NP-GL by primary cultured rat hepatocytes in vitro was higher, compared to the control-VACV-BSA-NP. 69.89% and 64.82% of the VACV were concentrated in liver at 15 min after i.v. VACV-BSA-NP-GL and VACV-BSA-NP, respectively. There is a significant difference between surface-modified group and control group (P<0.10). VACV-BSA-NP-GL was successfully prepared, which is considered to be a novel drug delivery system for targeting to hepatocytes.