Preparation and gastrointestinal absorption kinetics of tacrolimus solid dispersion / 中国药科大学学报

@#To prepare tacrolimus solid dispersion to increase the solubility and bioavailability of tacrolimus. Tacrolimus solid dispersions were prepared by different water-soluble carriers, which were evaluated by in vitro drug dissolutions to select the optimal formulation. The optimal tacrolimus solid dispersion was evaluated by scanning electron microscopy(SEM), X-ray diffraction(XRD)and differential scanning calorimetry(DSC), and its gastrointestinal absorption kinetics was studied in rats. The results showed that tacrolimus solid dispersion with HPMC E3 as carrier had the fastest dissolution rate. SEM, XRD and DSC studies indicated that tacrolimus was distributed within the carrier HPMC E3 in amorphous form. Gastrointestinal absorption experiments in rats demonstrated that the optimal formulation remarkably increased oral absorption of tacrolimus. These results demonstrate that a novel tacrolimus solid dispersion with HPMC E3 as carrier may be an advantageous dosage form of tacrolimus, boosting the solubility and absorption in gastrointestinal tract.

Proteomic approaches to study epigallocatechin gallate-provoked apoptosis of TSGH-8301 human urinary bladder carcinoma cells: roles of AKT and heat shock protein 27-modulated intrinsic apoptotic pathways.

Epigallocatechin-3-gallate (EGCG), a polyphenol constituent present in green tea, has been shown to inhibit the growth of cancer cells in vitro and in vivo. However, studies regarding human bladder carcinoma cells are limited and not well investigated. Hence, our study focused on the evaluation of EGCG-triggered apoptosis in TSGH-8301 human urinary bladder carcinoma cells in vivo and in vitro as well as its related molecular mechanisms. In an in vivo study, EGCG inhibited xenograft tumor size of TSGH-8301 cells in a nude mouse model. Based on an in vitro study, EGCG resulted in morphological changes and increased growth inhibition in a dose- and time-dependent manner in TSGH-8301 cells. Furthermore, sub-G1 populations were shown and caspase-9 and -3 activities were stimulated in EGCG-treated TSGH-8301 cells. Moreover, a caspase-9 inhibitor (Z-LEHD-FMK) and a caspase-3 inhibitor (Z-DEVD-FMK) were able to reduce EGCG-stimulated caspase-9 and -3 activities, respectively. Loss of mitochondrial membrane potential (∆Ψm) resulted in an increase of protein levels of cytochrome c, Apaf-1, caspase-9 and -3 in TSGH-8301 cells following exposure to EGCG. Proteomic analysis revealed that EGCG affected the expression levels of various proteins, including HSP27, porin, tropomyosin 3 isoform 2, prohibitin and keratin 5, 14, 17 in TSGH-8301 cells. EGCG also suppressed AKT kinase activity and protein levels and also altered the expression levels of Bcl-2 family-related proteins such as Bcl-2, Bax, BAD and p-BAD. Based on the above findings, this study suggests that EGCG-provoked apoptotic death in TSGH-8301 cells is mediated through targeting AKT and HSP27 and modulating p-BAD, leading to activation of the intrinsic apoptotic pathway.

Allyl isothiocyanate triggers G2/M phase arrest and apoptosis in human brain malignant glioma GBM 8401 cells through a mitochondria-dependent pathway.

Isothiocyanates (ITCs) are present as glucosinolates in various cruciferous vegetables. Allyl isothiocyanate (AITC) is one of the common naturally occurring isothiocyanates. Recent studies have shown that AITC significantly inhibited survival of leukemia HL-60, bladder cancer UM-UC-3 and colon cancer HT-29 cells in vitro. In this study, we demonstrate that AITC significantly decreased proliferation and viability of human brain malignant glioma GBM 8401 cells in a dose-dependent manner with IC50 9.25+/-0.69 microM for 24 h-treatment. The analysis of cell cycle distribution also showed that AITC induced significantly G2/M arrest and sub-G1 phase (apoptotic population) in GBM 8401 cells. AITC markedly reduced the CDK1/cyclin B activity and protein levels by CDK1 activity assay and Western blot analysis. AITC-induced apoptotic cell death and this evidence was confirmed by morphological assessment and DAPI staining. Pretreatment with specific inhibitors of caspase-3 (Z-DEVE-FMK) and -9 (Z-LEHD-FMK) significantly reduced caspase-3 and -9 activity in GBM 8401 cells. Western blot analysis and colorimetric assays also displayed that AITC caused a time-dependent increase in cytosolic cytochrome c, pro-caspase-9, Apaf-1, AIF, Endo G and the stimulated caspase-9 and -3 activity. Our results suggest that AITC is a potent anti-human brain malignant glioma drug and it shows a remarkable action on cell cycle arrest before commitment for apoptosis is reached.