Solubility of Gliclazide in Transcutol + Water Co-solvent Mixtures at (298.15 to 333.15) K

The aim of present investigation was to determine the mole fraction solubility of a poorly water soluble antidiabetic drug gliclazide (GLZ) in mono-solvents and various Transcutol + water co-solvent mixtures at (298.15 to 333.15) K. The experimental solubility of GLZ was measured by shake flask method and resulting data was correlated with the modified Apelblat model at each temperature studied. Good correlation was observed between the experimental data of GLZ and calculated one with absolute relative deviation in the range of (0.050 to 5.680) %. The correlation coefficients were observed in the range of 0.9966 to 0.9995 which indicated good fitting of experimental solubility data. The lowest mole fraction solubility of GLZ was observed in pure water (1.9 × 10–6 at 298.15 K) whereas the highest one was observed in pure Transcutol (11.9 × 10–3 at 298.15 K). The enthalpies and entropies for GLZ dissolution were observed as positive values in the range of (15.742 to 40.551) kJ mol–1 and (52.801 to 121.721) J mol–1 K–1, respectively in all sample matrices. These results of thermodynamic parameters indicated that the dissolution of GLZ is endothermic and an entropy-driven process. Based on current solubility data, GLZ was considered as practically insoluble (poorly soluble) in pure water and soluble in Transcutol. These preliminary studies indicated that Transcutol could be used as a co-solvent for solubility enhancement of GLZ which could help in preformulation studies and formulation development of GLZ

Hepatocellular proliferation in response to agonists of peroxisome proliferator-activated receptor alpha: a role for kupffer cells?

BACKGROUND: It has been proposed that PPARα agonists stimulate Kupffer cells in rodents which in turn, release mitogenic factors leading to hepatic hyperplasia, and eventually cancer. However, Kupffer cells do not express PPARα receptors, and PPARα agonists stimulate hepatocellular proliferation in both TNFα- and TNFα receptor-null mice, casting doubt on the involvement of Kupffer cells in the mitogenic response to PPARα agonists. This study was therefore designed to investigate whether the PPARα agonist PFOA and the Kupffer cell inhibitor methylpalmitate produce opposing effects on hepatocellular proliferation and Kupffer cell activity in vivo, in a manner that would implicate these cells in the mitogenic effects of PPARα agonists. METHODS: Male Sprague-Dawley rats were treated intravenously via the tail vein with methylpalmitate 24 hrs prior to perfluorooctanoic acid (PFOA), and were sacrificed 24 hrs later, one hr after an intraperitoneal injection of bromodeoxyuridine (BrdU). Sera were analyzed for TNFα and IL-1β. Liver sections were stained immunohistochemically and quantified for BrdU incorporated into DNA. RESULTS: Data show that PFOA remarkably stimulated hepatocellular proliferation in the absence of significant changes in the serum levels of either TNFα or IL-1β. In addition, methylpalmitate did not alter the levels of these mitogens in PFOA-treated animals, despite the fact that it significantly blocked the hepatocellular proliferative effect of PFOA. Correlation between hepatocellular proliferation and serum levels of TNFα or IL-1β was extremely poor. CONCLUSION: It is unlikely that mechanisms involving Kupffer cells play an eminent role in the hepatic hyperplasia, and consequently hepatocarcinogenicity attributed to PPARα agonists. This conclusion is based on the above mentioned published data and the current findings showing animals treated with PFOA alone or in combination with methylpalmitate to have similar levels of serum TNFα and IL-1β, which are reliable indicators of Kupffer cell activity, despite a remarkable difference in hepatocellular proliferation

Development of a new medium containing date syrup for production of bleomycin by Streptomyces mobaraensis ATCC 15003 using response surface methodology

A combined statistical approach of orthogonal design and polynomial regression were applied to optimize the composition and concentration of a liquid fermentation medium for the production of bleomycin (BLM) by Streptomyces mobaraensis. Optimal conditions for maximal productivity were determined based on eight parameters at three different levels. The sources of carbon and nitrogen concentration and their interactions with other precursors were found to be statistically significant factors. When date syrup was used as an additional carbon source, higher BLM amount was obtained in comparison to glucose. It was found that the optimum nitrogen source was achieved with the use of soyabean meal. The combined orthogonal design and response surface methodology predicted optimal conditions for production of BLM to be 138 mg dl-1. A confirmatory experiment of the optimal medium composition produced 142 mg dl-1 in the fifth day fermentation at 30°C. The complex medium containing 40 gml-1 date syrup as additional carbon source enhanced the production of BLM by 73%. The combined statistical approach enabled rapid identification and integration of key medium parameters for optimizing secondary metabolite production and could be very useful in pharma-ceutical screening programs.Keywords: Bleomycin, Streptomyces mobaraensis, orthogonal design, medium optimization, date syrupAfrican Journal of Biotechnology Vol. 9(33), pp. 5450-5459, 16 August, 201

Physical pegylation enhances the cytotoxicity of 5-fluorouracil-loaded PLGA And PCL nanoparticles.

Purpose : The main goal of this study is to evaluate the impact of physical incorporation of polyethylene glycol (PEG) into 5-fluorouracil (5-FU)-loaded polymeric nanoparticles (NPs). METHODS: The 5-FU-loaded NPs were prepared utilizing a simple double emulsion method using polycaprolactone (PCL) and polylactic-co-glycolic acid (PLGA) with or without PEG 6000. The surface charge, particle size, and shape of NPs were evaluated by standard procedures. Both Fourier Transform Infrared Spectroscopy and X-ray diffraction spectra of the 5-FU loaded NPs were compared against the pure 5-FU. The in vitro release profile of 5-FU from the NPs was monitored by the dialysis tubing method. Cell death and apoptosis induction in response to 5-FU NP exposure were measured by MTT and Annexin-V/7-amino-actinomycin D (7-AAD) assays, respectively, in Daoy, HepG2, and HT-29 cancer cell lines. RESULTS: The 5-FU loaded NPs were found to be spherical in shape with size ranging between 176±6.7 and 253.9±8.6 nm. The zeta potential varied between -7.13± 0.13 and -27.06±3.18 mV, and the entrapment efficiency was between 31.96% and 74.09%. The in vitro release of the drug followed a two-phase mode characterized by rapid release in the first 8 hrs followed by a period of slow release up to 72 hrs with composition-based variable extents. Cells exposed to NPs demonstrated a significant cell death which correlated with the ratio of PEG in the formulations in Daoy and HepG2 cells but not in HT-29 cells. Formulations (F1-F3) significantly induced early apoptosis in HT-29 cell lines. CONCLUSION: The physical PEGylation significantly enhanced the entrapment and loading efficiencies of 5-FU into NPs formulated with PLGA and PCL. It also fostered the in vitro cytotoxicity of 5-FU-loaded NPs in both Daoy and HepG2 cells. Induction of early apoptosis was confirmed for some of the formulations

Solubility and Thermodynamics Data of Cabozantinib Malate in Various Aqueous Solutions of Dimethyl Sulfoxide at Different Temperatures

Cabozantinib malate (CBZM), a new anticancer medication, has been studied for its solubility and thermodynamic properties in a variety of {dimethyl sulfoxide (DMSO) + water (H2O)} mixtures at 298.2–318.2 K and 101.1 kPa. Using the shake flask technique, the solubility of CBZM was assessed and the results were correlated to the van’t Hoff, Apelblat, Buchowski–Ksiazczak λh, Yalkowsky–Roseman, Jouyban–Acree, and Jouyban–Acree-van’t Hoff models. There was a significant correlation between the experimental CBZM solubility data and all computational models, as evidenced by the error values for all computational models being less than 5.0%. Temperature and DMSO mass percentage improved the CBZM mole fraction solubility in the cosolvent solutions of {DMSO + H2O}. At 318.2 K, pure DMSO had the highest mole fraction solubility of CBZM (4.38 × 10−2), whereas pure H2O had the lowest mole fraction solubility (2.24 × 10−7 at 298.2 K). The positive values of computed thermodynamic parameters indicated that the dissolution of CBZM was endothermic and entropy-driven in all of the {DMSO + H2O} solutions investigated. It was found that the CBZM solvation in {DMSO + H2O} solutions is governed by enthalpy. When compared to CBZM-H2O, CBZM-DMSO showed the highest molecular interactions. The findings of this investigation demonstrated that DMSO has a great deal of potential for CBZM solubilization in H2O