Wei-Nong Zhang

Butanol production from corncob residue using Clostridium beijerinckii NCIMB 8052

Aims:  To determine whether corncob residue (CCR) could be a good substrate for butanol production.

[Preparation of magnesia-zirconia based mimetic biomembrane stationary phase and its applications in evaluating drug-membrane interactions].

A novel mimetic biomembrane chromatographic stationary phase of magnesia-zirconia composite matrix was prepared based on the Lewis acid-base interaction between the phosphonate group of phosphatidylcholine residue and the Lewis acid sites of magnesia-zirconia composite. The infrared absorption spectrum and X-ray photoelectron spectrum of the stationary phase illustrated that the magnesia-zirconia composite was successfully modified with phosphatidylcholine. The interactions between the membrane and the drugs were evaluated. It is observed that the log Kmbm values have good relationships with the log Papp, and the linear slope is 1.049, which is near unity. Moreover, on the basis of the thermodynamics derivation, the difference in standard free energies (delta (delta G0)) is introduced to describe the drug-membrane interaction. The results show that the log Kmbm, and delta (delta G0) value provide key information on the transport properties of the drugs. The establishment of this chromatographic model may be a new way for the evaluation of the drug-membrane interactions.

Preparation and characterization of phosphatidylcholine-coated zirconia–magnesia stationary phase for artificial membrane chromatography

Immobilized artificial membrane chromatography stationary phase was prepared by coating soybean phosphatidylcholine (PC) on zirconia-magnesia micro-particles. The stability and chromatographic properties were investigated and compared with the PC-coated silica chromatography stationary phase prepared by the same method. PC-coated zirconia-magnesia chromatography stationary phase was more stable than the silica especially on resisting organic solvents. Hydrophobic action was the main factor for the retention of analyte on the new artificial membrane chromatography stationary phase, and electrostatic interaction had some contribution to retention. In addition, the special interaction between analyte and matrix affected retention greatly. Basic solutes were appropriate to be analyzed on PC-coated zirconia-magnesia stationary phase and acidic solutes were appropriate to be done on the silica one. Hence, the two different matrices artificial membrane stationary phases were perfectly complementary.

Dynamic lipid profile of hyperlipidemia mice

Biomarkers of serum fatty acids in hyperlipidemia need to be elucidated. 90 SPF KM male mice were randomly divided into 18 groups (n=5/group), control groups, and high fat diet (HFD) groups at 9 time points. On day 7, 10, 15, 18, 21, 24, 28, 31, and 35, the mice were sacrificed; blood was collected into tubes from the eyes, serum samples for clinical biochemistry assays and gas chromatography-mass spectroscopy were attained after centrifugation, and the contents of serum fatty acids were detected with GC-MS. Sections of livers were taken and stored in formalin solution for histological assessments. No species differences existed in all these groups. The contents of C16:1, C18:1, C22:6 were significantly different between HFD groups and the corresponding controls; meanwhile, the proportion of fatty acids, especially the monounsaturated degree, the polyunsaturated degree, changed significantly and regularly (P<0.05). Thus the three unsaturated fatty acids C16:1, C18:1, C22:6 and the monounsaturated/polyunsaturated unsaturated degrees may be as potential biomarkers of hyperlipidemia.

Study on interaction between drug and membrane by using liposome coated zirconia-magnesia chromatography

The interactions between drug molecules and membrane were studied using the new chromatography stationary phase of liposome coated zirconia-magnesia. logK(s)(ZrO(2)-MgO) on this new chromatography for some drugs, compared with that on liposome coated silica chromatography and other reported data, fair correlations were observed between them when excluding effect of special adsorption. logK(s)(ZrO(2)-MgO) values for barbitalum, diazepam, benzene, benzocaine and toluene correlated well with corresponding values on liposome coated silica chromatography (R=0.99778, P<0.001; R=0.98229, P<0.003; R=0.9985, P<0.0001; R=0.99925, P<0.0001, pH value of mobile phase at pH 7.4, 7.0, 6.4 and 5.4, respectively). They also correlated well with the literature data on immobilized artificial membrane chromatography (R=0.99999, P<0.004 at pH 7.4) and liposome chromatography (R=0.99994, P<0.008) for procaine, lidocaine and bupivacaine. Liposome coated zirconia-magnesia chromatography can thus be used for studying drug-membrane interaction and prediction of drug absorption as another liposome chromatography method.