The Influence of Cellulosic Polymer's Variables on Dissolution/Solubility of Amorphous Felodipine and Crystallization Inhibition from a Supersaturated State.

The collective impact of cellulosic polymers on the dissolution, solubility, and crystallization inhibition of amorphous active pharmaceutical ingredients (APIs) is still far from being adequately understood. The goal of this research was to explore the influence of cellulosic polymers and incubation conditions on enhancement of solubility and dissolution of amorphous felodipine, while inhibiting crystallization of the drug from a supersaturated state. Variables, including cellulosic polymer type, amount, ionic strength, and viscosity, were evaluated for effects on API dissolution/solubility and crystallization processes. Water-soluble cellulosic polymers, including HPMC E15, HPMC E5, HPMC K100-LV, L-HPC, and MC, were studied. All cellulosic polymers could extend API dissolution and solubility to various extents by delaying crystallization and prolonging supersaturation duration, with their effectiveness ranked from greatest to least as HPMC E15 > HPMC E5 > HPMC K100-LV > L-HPC > MC. Decreased polymer amount, lower ionic strength, or higher polymer viscosity tended to decrease dissolution/solubility and promote crystal growth to accelerate crystallization. HPMC E15 achieved greatest extended API dissolution and maintenance of supersaturation from a supersaturated state; this polymer thus had the greatest potential for maintaining sustainable API absorption within biologically relevant time frames.

[Analysis of Observers Metamerism Differences for Different Retinal Cone Visual Responses].

In order to investigate the cone's spectral responses under different conditions for different aged observers with normal color vision, nine color patches with different hue angles distributed uniformly on the CIELAB color space were prepared, and the 27-35 observers were organized to carry out color matching experiments on a monitor to match the nine printed color samples under four different viewing conditions including two illuminances, and two viewing fields. The spectral data obtained from the color matching experiments were compared with the spectral data of the nine target colors and used to test the performances of eleven color matching functions including CIE1931, CIE1964, CIE2006, Sarkar's S1-S8 in terms of the percentage of the minimum CIEDE2000 value. For the four experiments, CIE2006 and S6 performed the best and with S1, S2 the worst. For different observers, the visual spectral responses' of the retinal cone are different and the age has the obvious influence on the visual spectral responses. The observer metamerism is mainly caused by the different spectral response of the (A) channel and for most observers the differences appeared at the responses of the peak wavelength, and the shift of the peak wavelength has no significant influence on the observers metamerism. The experimental results can provide evidences for the classification of the color matching functions for different observer categories and theoretical basis for the investigation of the observers metamerism.

[Colorimetric characterization of LCD based on wavelength partition spectral model].

To establish a colorimetrical characterization model of LCDs, an experiment with EIZO CG19, IBM 19, DELL 19 and HP 19 LCDs was designed and carried out to test the interaction between RGB channels, and then to test the spectral additive property of LCDs. The RGB digital values of single channel and two channels were given and the corresponding tristimulus values were measured, then a chart was plotted and calculations were made to test the independency of RGB channels. The results showed that the interaction between channels was reasonably weak and spectral additivity property was held well. We also found that the relations between radiations and digital values at different wavelengths varied, that is, they were the functions of wavelength. A new calculation method based on piecewise spectral model, in which the relation between radiations and digital values was fitted by a cubic polynomial in each piece of wavelength with measured spectral radiation curves, was proposed and tested. The spectral radiation curves of RGB primaries with any digital values can be found out with only a few measurements and fitted cubic polynomial in this way and then any displayed color can be turned out by the spectral additivity property of primaries at given digital values. The algorithm of this method was discussed in detail in this paper. The computations showed that the proposed method was simple and the number of measurements needed was reduced greatly while keeping a very high computation precision. This method can be used as a colorimetrical characterization model.

A coordination polymer of Cd with benzene-1,3-dicarboxyl-ate and 1,4-bis-[1-(2-pyridylmeth-yl)benzimidazol-2-yl]butane.

The title Cd(II) coordination polymer, catena-poly[[{1,4-bis-[1-(2-pyridylmeth-yl)benzimidazol-2-yl]butane}cadmium(II)]-µ-benzene-1,3-dicarboxyl-ato], [Cd(C(8)H(4)O(4))(C(30)H(28)N(6))](n), was obtained by reaction of CdCO(3), benzene-1,3-dicarboxylic acid (H(2)btc) and 1,4-bis-[1-(2-pyridylmeth-yl)benzimidazol-2-yl]butane (L). The Cd(II) cation is six-coordinated by an N(2)O(4)-donor set. L acts as a bidentate ligand and btc anions link Cd(II) centers into a chain propagating parallel to [010].

6,6'-Dihydr-oxy-3,3'-dithio-dibenzoic acid.

In the title compound, C(14)H(10)O(6)S(2), the dihedral angle between the planes of the two phenyl-ene rings is 55.9 (1)°. Both hydr-oxy groups form intra-molecular hydrogen bonds; however, one of them also engages in inter-molecular hydrogen bonding. In the crystal, mol-ecules are connected into helical chains by O-H⋯O hydrogen bonds. The crystal studied was an inversion twin with a domain ratio of 0.51 (13):0.49 (13).