Microspherical Particles of Solid Dispersion of Polyvinylpyrrolidone K29-32 for Inhalation Administration.

Inhalation administration is a promising alternative to the invasive drug delivery methods. The particle size required for ideal drug aerosol preparation is between 1 and 3 µm. The application of microspherical particles of solid dispersions enhances bioavailability of poorly soluble drugs due to the solubilization. In the present work, the spray drying process of the production of microspherical particles of solid dispersions of polyvinylpyrrolidone K29-32 with model hydrophobic drug, phenacetin, was optimized using the results of DSC, PXRD, and viscometry. The diameter of the obtained particles is within 1-3 µm range. The Gibbs energy of dissolution in water was shown to be negative for the mixture with polymer/phenacetin mass ratio 5 : 1. We have demonstrated that the optimal size distribution for the inhalation administration is obtained for microspherical particles produced using spray caps with 7.0 µm hole size. The dissolution rates of phenacetin from the produced microspherical particles were faster than that of drug powder. As evidenced by powder X-ray diffraction data, phenacetin stayed in amorphous state for 4 months in microspherical particles of solid dispersions. According to the obtained results, strategic application of the spray drying process could be beneficial for the improvement of the pharmaceutical properties of model drug, phenacetin.

Structural and spectral characterization of novel non-centrosymmetric 2,4-dintrobenzene derivative.

A novel organic compound 9-(2,4-dinitrophenyloxy)-3,3,8-trimethyl-1,5-dihydro-[1,3]dioxepino[5,6-c]pyridine (DNPAP) has been synthesized and a nonlinear optical (NLO) crystal has been grown by slow evaporation method. Compound was subjected to different characterization analyses in order to find out its suitability for optoelectronic applications. Single crystal and powder X-ray diffraction analyses show that DNPAP crystallizes in the orthorhombic space group Pca21. The range of optical absorption was ascertained by recording UV­Vis spectrum. The second harmonic generation (SHG) test has shown that DNPAP possesses 6.4-times higher NLO efficiency compared to KDP.

The vibrational spectra and conformations of ethylbenzene.

Infrared spectra (4000-250 cm-1) of the liquid, amorphous, crystalline solids and solutions in liquid krypton and Raman spectra (2500-20 cm-1) of the liquid as well as the amorphous and crystalline solids of ethylbenzene and its deuterated analogue-ethylbenzene-d(10) have been recorded. The spectra indicate that in the liquid and amorphous solids a small amount of a second conformer is present, whereas only one conformer remains in the crystalline phases. Assignments of the observed band wave numbers are discussed by comparison with normal mode wave numbers and IR and RS intensities calculated from ab initio 6-31G force fields and optimised geometries for both conformers for two species. All of the normal modes of conformers have been assigned.