Tenoxicam-kollicoat IR binary systems: physicochemical and biological evaluation.
Tenoxicam (TNX) binary systems in Kollicoat IR (KL) matrix were prepared in different drug: polymer ratios using kneading and spray-drying method. The prepared binary systems were characterized for drug dissolution rate, differential scanning calorimetry (DSC), IR spectroscopy and x-ray diffractometry. The results showed that the drug dissolution rate was remarkably enhanced by incorporating it in the KL matrix either by kneading or spray-drying, and the dissolution rate was increased by decreasing the drug weight ratio. The DSc and x-ray studies revealed the presence of TNX in less crystalline or amorphous state in its-KL binary systems. Moreover, the spray-dried TNX-KL system in 1:4 ratio, that exhibited the faster dissolution rate, was formulated in oral disintegrating tablets (ODTs). The data indicated that a fast disintegration and higher drug dissolution rate was achieved in case of the ODTs containing the spray-dried form compared to the ODTS containing untreated drug or the commercial tablet (Epicotil). Also, the drug exhibited significantly (p < 0.01) faster onset of the anti-inflammatory analgesic activities in case of the ODTs containing the spray-dried form, that was superior to that observed with both the commercial tablet product and the ODTS containing untreated drug.
Rosuvastatin calcium nanoparticles: Improving bioavailability by formulation and stabilization codesign
Purpose Rosuvastatin calcium (ROSCa) is a poorly soluble drug with bioavailability not exceeding 20%. Decreasing the particle size may enhance its solubility, dissolution rate and bioavailability. Therefore, the aim of the current study is to prepare ROSCa nanoparticles by wet milling technique using planetary ball mill. The codesign between formulation and stabilization of nanoparticles was studied to achieve both high dissolution as well as bioavailability. Methodology ROSCa nanosuspensions was prepared by wet milling technique using planetary ball mill, by applying milling ball size of 0.1 mm at speed of 800 rpm for 3 cycles each cycle composed of 10 minutes. HPMC, PVP k-30, pluronic F-127, Tween 80 and PEG 6000 were used as stabilizers. The nanosuspensions were then freeze-dried, and the dried nanoparticles were evaluated for particle size, zeta potential, in-vitro dissolution test, XRPD and in-vivo study. Results ROSCa nanoparticles stabilized with 10% PVP (P3) had a good stability with smallest particle size, which in turn enhanced the dissolution rate. The particle size of the leading formula was 461.8 ± 16.68 nm with zeta potential of -31.8 ± 7.22 mV compared to untreated drug that has a particle size of 618μm. The percent of ROSCa dissolved after 1 hour enhanced significantly which reached 72% and 58.25% for leading nanoparticle formula and untreated ROSCa, respectively (P < 0.05). The in-vivo study of ROSCa from the leading nanoparticle formula showed a significant enhancement in the Cmax after 2 h (82.35 ng/ml) compared to 9.2 ng/ml for untreated drug. Conclusion Wet milling technique is a successful method to prepare ROSCa nanoparticles. From different stabilizer used, PVP (10%) was able to produce stable nanoparticle with small particle size which significantly enhance the dissolution rate and pharmacokinetics parameters of ROSCa.
Concentration of amino acids in wine after the end of fermentation by Saccharomyces cerevisiae strains
Both quantitative and qualitative differences in the utilization and release of assimilable nitrogen by two wine strains of Saccharomyces cerevisiae (cerevisiae and capensis) under different conditions of oxygen were observed. These differences were influenced by the presence of oxygen at the beginning of the fermentation, and by the strain of S cerevisiae. The release of some amino acids post-fermentation may be the result of reoxidation of NAD(P)H in order to maintain a normal redox balance. Copyright © 2003 Society of Chemical Industry