Pilot Scale Test to Treat High Concentration Gasification Wastewater Using Catalytic Oxidation and Aerobic Biological Fluid-Bed Combination Process

The gasification wastewater is a kind of typical organic industrial wastewater with high chemical oxygen demand （COD） and ammonia nitrogen, which could not be completely degraded by the traditional physical, chemical and biological method. So it is very important to find an effective treatment process. A combination process of catalytic oxidation with noble metal catalysts and aerobic biological fluid-bed packed with the new ultrastructure biological carriers, which was developed by ourselves, was investigated to treat the gasification wastewater. The pilot scale test with 0.5 m^3/h influent flow was carried out to investigate the performance of this new combination process. The results showed that the effluent COD was 84.02 mg/L, ammonia nitrogen was 14.15 mg/L, and total phenol was 0.20 mg/L, which could completely meet the Grade I of Wastewater Discharge Standard （GB8978-1996）, when the influent average COD was 5 564 mg/L, ammonia nitrogen was 237 mg/L, and total phenol was 1 100 mg/L. The two catalytic reactors could evidently improve the wastewater biodegradability, and the value of BOD5/COD （B/C） increased from 0.23 to 0.413 in the one-stage catalytic reactor and from 0. 273 to 0.421 in two-stage catalytic reactor. The further experiment results showed that the effluent quality of this new combination process could still meet the discharge standard, when the COD loading was 8.65 kg / （m^3· d）. Most of aromatic and heterocyclic compounds were degraded effectively in this combination process.

Fenofibrate solid dispersion pellets prepared by fluid-bed coating:physical characterization,improved dissolution and oral bioavailability in beagle dogs

Solid dispersion of fenofibrate （FNB）, a poorly water-soluble drug, was prepared by a fluid-bed coating technique with PEG 6000 as the carrier. The physical state was characterized by DSC and X-ray powder diffractometry, which indicated the existence of fenofibrate in crystalline form in the solid dispersion. In vitro dissolution was studied in water containing 1% sodium lauryl sulfate, FASSIF and FESSIF. Significant enhancement in dissolution was achieved at PEG/FNB ratio of 4/1 with near complete dissolution within 30 min. Moderate improvement in dissolution rate was observed at smaller PEG/FNB ratios. Oral bioavailability was studied in beagle dogs after oral administration of fenofibrate solid dispersion pellets by monitoring fenofibric acid in plasma. The oral bioavailability of PEG/FNB 3/1 and 4/1 solid dispersion pellets was improved by 3.4 and 4.4-fold as compared to Lipanthyl, a commercial micronized fenotibrate formulation. There was a strong dependence of oral bioavailability on the in vitro dissolution rate. Good correlation was observed between the in vivo absorption fraction and the in vitro dissolution rate in each of the dissolution media, water containing 1% sodium lauryl sulfate, FASSIF and FESSIF. It could be concluded that PEG/FNB solid dispersion pellets were able to improve the dissolution and oral bioavailability of fenofibrate.

Application of defin让ive screening design to quantify the effects of process parameters on key granule characteristics and optimize operating parameters in pulsed-spray fluid-bed granulation

The pulsed-spray fluid-bed granulation (PSFBG) process was investigated and optimized using definitive scree ning design, a recently proposed new class of three-level desig n of experiment method. Such a design enabled quadratic models to be established that described the effect of six in put process parameters - inlet air temperature, inlet air humidity, binder spray rate, atomization pressure, pulse period, and pulse width - on the granule quality in a PSFBG process. Mathematical models of the mean particle size, relative size distribution width, production yield, and porosity were developed to quantify the relationships between the in flue ncing factors and critical quality attributes. On the basis of con strai nts on the desired granule properties, a design space for PSFBG was determined and ranges of the operating parameters were defined. An acceptable degree of prediction was confirmed by validation experiments, demonstrating the reliability and effectiveness of using definitive screening design to study the PSFBG process. This method can accelerate screening and optimization of this process within a large multidimensional design space.

Physical characterization of meloxicam-β-cyclodextrin inclusion complex pellets prepared by a fluid-bed coating method

Meloxicam-β-cyclodextrin （ME-β-CD） inclusion complex was prepared by a fluid-bed coating technique upon solvent removal and simultaneous depositing onto the surface of nonpareil pellets and using PVP K30 as a binding agent to facilitate good coating. The resultant pellets were spherical and intact in shape with good flowability and friability. SEM analysis showed that the pellets were smooth and had a tightly coated inclusion complex layer. In vitro dissolution of the inclusion complex pellets in pH 7.4 phosphate buffer was dramatically enhanced at an ME/CD ratio of 1/1. DSC and powder X-ray diffractometry proved the absence of crystallinity in the ME/CD inclusion complexes. Moreover, Fourier transform-infrared spectrometry together with Raman spectrometry indicated that the thiazole ring of ME was possibly included in the cavity of β-CD.

Cooperative effect of polyvinylpyrrolidone and HPMC E5 on dissolution and bioavailability of nimodipine solid dispersions and tablets

Solid dispersion(SD)systems have been extensively used to increase the dissolution and bioavailability of poorly water-soluble drugs.To circumvent the limitations of polyvinylpyrrolidone(PVP)dispersions,HPMC E5 was applied in the formulation process and scaling-up techniques,simultaneously.In this study,SD of nimodipine(NMP)and corresponding tablets were prepared through solvent method and fluid bed granulating one step technique,respectively.Discriminatory dissolution media were used to obtain reliable dissolution results.Meanwhile,the stability study of SDs was investigated with storage under high temperature and humidity conditions.Moreover,the solubility of SDs was measured to explore the effect of carriers.The preparations were characterized by DSC,PXRD,and FTIR.Dramatical improvements in the dissolution rate of NMP were achieved by the ingenious combination of the two polymers.Binary NMP/PVP/HPMC-SDs released steadily,while the dissolution of single NMP/PVP-SDs decreased rapidly in water.The fluid-bed tablets(FB-T)possessed a similar dissolution behavior to the commercial Nimotop TM tablets.The characterization patterns implied that NMP existed in an amorphous state in our SDs.Furthermore,the results of stability tests suggested a better stability of the binary SDs.A special cooperative effect of PVP and HPMC was discovered on dissolution characteristics of NMP SDs and tablets,which could be extended to other drugs henceforth.Finally,the bioavailability of FB-T was evaluated in beagle dogs with Nimotop TM as the reference,and the results showed a higher AUC 0–12h value for FB-T.

A quality by design (QbD) case study on entericcoated pellets: Screening of critical variables and establishment of design space at laboratory scale

The study aims to prepare naproxen enteric-coated pellets(NAP-ECPs)by fluid-bed coating using QbD principle.Risk assessment was firstly performed by using failure mode and effect analysis(FMEA)methodology.A PlacketteBurman design was then used for assessment of the most important variables affecting enteric-coated pellets characteristics.A BoxeBehnken design was subsequently used for investigating the main,interactive,and quadratic effects of these variables on the response.By FMEA we discovered that eight factors should be considered to be high/important risk variables as compared with others.The responses of acid resistance and cumulative drug release were taken as critical quality attributes(CQAs).Pareto ranking analyses indicated that the coating weight gain(X_(7)),triethyl citrate percentage(X_(1))and glycerol monostearate percentage(X_(2))were the most significant factors affecting the selected responses out of the eight high-risk variables.Optimization with response surface method(RSM)further fully clarified the relationship between X_(7),X_(1),X_(2) and CQAs,and design space was established based on the constraints set on the responses.Due to the extreme coincidence of the predicted value generated by model with the observed value,the accuracy and robustness of the model were confirmed.It could be concluded that a promising NAP-ECPs was successfully designed using QbD approach in a laboratory scale.