Nickel oxide/cobalt phthalocyanine (NiO– CoPc) nanocomposite is synthesized by solvent evaporation method. The synthesized nanocomposite is characterized for thermal, structural, and optical properties. Thermogravimetric and differential thermal analysis results proved the thermal stability of the sample. XRD patterns revealed an average crystallite size of 16 and 17. 5 nm, respectively, for the pure and nanocomposite samples. The formation of NiO/CoPc nanocomposite is confirmed by the FTIR results. The characteristic B and Q bands of metal phthalocyanines are visible in the absorption spectrum. A decrease in band gap and an enhanced absorption in the visible region are observed for the nanocomposite. The PL emission spectrum of the nanocomposite exhibits fluorescence quenching which makes them suitable for solar cells and photocatalysis. This work constitutes the first report on the synthesis and characterization of the NiO/CoPc nanocomposite.

Glibenclamide (GLIB) is a poorly soluble drug with formulation-dependent bioavailability. Therefore, we attempted in this study to improve GLIB dissolution rate by preparing drug solid dispersions by solvent evaporation (SE) and supercritical fluid solvent-antisolvent techniques (SCF-SAS). A D-optimal mixture design was used to investigate the effects of different ratios of HPMCE5 (50-100%), PEG6000 (0-40%), and Poloxamer407 (0-20%) on drug dissolution from different solid dispersion (SD) formulations prepared by SE. The ratios of carriers used in SCF-SAS method were HPMCE5 (fixed at 60%), PEG6000 (20-40%), and Poloxamer407 (0-20%). A constant drug: carrier weight ratio of 1:10 was used in all experiments. The SDs obtained were physically characterized and subjected to the dissolution study. The major GLIB bands in FTIR spectra were indicative of drug integrity. The reduced intensity and the fewer number of peaks observed in X-ray diffractograms (XRD) of GLIB formulations was the indicative of at least partial transformation of crystalline to amorphous GLIB. This change and/or dilution of drug in much higher amounts of carriers present caused disappearance of distinctive endothermic peaks in differential scanning calorimetry thermograms of GLIB formulations. The model generated according to the results of the D-optimal mixture design indicated that GLIB formulations comprising HPMC (50%-60%), PEG (34-40%), and poloxamer (6-10%) had enhanced dissolution performances. As compared to SE method, the SCF-SAS technique produced formulations of higher dissolution performances, likely due to the effects of solution and the supercritical CO2 (SC-CO2) on enhanced plasticization of polymers and thus increased diffusion of the drug into the polymer matrix.

Preparation and characterization of nifedipine microspheres using ethylcellulose as matrix polymer is described. Nifedipine microspheres were prepared by solvent evaporation technique. The influence of different parameters such as the effect of the concentration of internal and external phases, the amount of drug and the rate of stirring of the medium on the size distribution of microspheres was studied. The effect of drug/polymer ratio and mean particle size on the drug release pattern was also evaluated. Drug release from nifedipine microspheres was studied in a medium, which simulated the change in pH of the pathway of the microspheres from stomach to intestine. It was found that with increase in the concentration of the internal phase, the size of microspheres became larger. Increasing the amount of polyvinyl alcohol in the external phase reduced the size of microspheres. Dissolution was found to be inversely related to the pH, in a way that drug release decreased at higher pH: Drug release from microspheres with small mean particle size was faster than those with large mesh particle size and followed Higuchi model of kinetics.