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Introduction: This study aimed to evaluate the anti-cancer effects of gedunin, a natural compound, in a rat model of gastric carcinogenesis induced by MNNG. Methods: Fifty-four rats were randomly assigned to six groups for a 60-day study on the effects of MNNG and gedunin. Groups 1-4 received 200 mg/kg MNNG (1, 10, or 100 mg/kg), and group 5 had only 100 mg/kg gedunin. Results: Gedunin at low doses exhibited anti-cancer and protective properties against MNNG-induced damage, including reduced inflammation, and apoptosis. Conclusions: Gedunin demonstrates a U-shaped dose-response, with low doses offering protection and high doses promoting tumor growth. [ABSTRACT FROM AUTHOR]

The objective of this study was to prepare azithromycin (AZI) sustained-release products in order to allow for a high dose to be administered, reduce gastrointestinal side-effects and increase the compliance of patients. AZI sustained-release tablets with different release performance (F-I: T100% = 3 h and F-II: T100% = 8 h in pH 6.0 phosphate buffer) were successfully prepared by wet granulation. The in vitro release rate and drug release mechanism were studied. The release rate of F-I was affected by dissolution media with different pH, but not for F-II. Hixsone-Crowell model was the best regression fitting model for F-I and F-II. Additionally, F-I and F-II both belonged to non-Fick diffusion. Oral pharmacokinetics of the two tablets and one AZI dispersible tablet as reference were studied in six healthy beagle dogs after oral administration. Compared with the reference, the Cmax of F-I and F-II were decreased, and the Tmax were prolonged, in that case which meet the requirement of sustained-release tablets. The relative bioavailability of F-I and F-II were 79.12% and 64.09%. T-test of AUC0-144, and AUC0 -∞ for F-I and F-II indicated there was no significant difference between F-I and F-II. These mean that the extended release rate did not induce different pharmacokinetics in vivo. [ABSTRACT FROM AUTHOR]

With the aid of the variational method and Laplace transformation, the symplectic system method is employed into two-dimensional elastic–viscoelastic fiber reinforced composites. The fundamental eigenfunctions of the governing equations are generalized to the time domain. Therefore the problem can be discussed directly in the time domain, and the iterative application of Laplace transformation is not needed. Using this method, all the stress components of the inner fiber and outer matrix, and hence the stress transfer in the interface between the fiber and matrix, are expressed analytically. The results obtained by the approach are accurate, because all the boundary conditions prescribed on the surfaces and ends of the composites can be satisfied. Numerical example demonstrate that both the shear stress and the normal stress decrease with time due to the viscoelastic property of the matrix, and that stress concentration occurs near the end. [ABSTRACT FROM AUTHOR]

Abstract  The traditional Saint-Venant problem of three-dimensional viscoelasticity is discussed under the Hamiltonia system with the use of the Laplace integral transformation, and the original problem is transformed into finding eigenvalues and eigenvectors of the Hamiltonia operator matrix. Since local effect near the boundary is usually neglected, all solutions of Saint-Venant problems can be obtained directly by the combinations of zero eigenvectors. Moreover, the adjoint relationships of the symplectic orthogonality of zero eigenvectors in the Laplace domain are generalized to the time domain. Therefore the problem can be discussed directly in the eigenvector space of the time domain, and the iterative application of Laplace transformation is not needed. Simply by applying the adjoint relationships of the symplectic orthogonality, an effective method for boundary condition is given. Based on this method, some typical examples are discussed, in which the whole character of total creep and relaxation of viscoelasticity is clearly revealed. [ABSTRACT FROM AUTHOR]

Background: Solid dispersions are an effective formulation technique to improve the solubility, dissolution rate, and bioavailability of water-insoluble drugs for oral delivery. In the last 15 years, increased attention was focused on this technology. There were 23 marketed drugs prepared by solid dispersion techniques. Objective: This study aimed to report the big picture of solid dispersion research from 1980 to 2015. Method: Scientific knowledge mapping tools were used for the qualitative and the quantitative analysis of patents and literature from the time and space dimensions. Results: Western Europe and North America were the major research areas in this field with frequent international cooperation. Moreover, there was a close collaboration between universities and industries, while research collaboration in Asia mainly existed between universities. The model drugs, main excipients, preparation technologies, characterization approaches and the mechanism involved in the formulation of solid dispersions were analyzed via the keyword burst and co-citation cluster techniques. Integrated experimental, theoretical and computational tools were useful techniques for in silico formulation design of the solid dispersions. Conclusions: Our research provided the qualitative and the quantitative analysis of patents and literature of solid dispersions in the last three decades. [ABSTRACT FROM AUTHOR]