Apolipoprotein E Gene Polymorphisms in Saudi Patients with Systemic Lupus Erythematosus.

Apolipoprotein E (APOE) is a glycosylated protein with multiple biological properties. APOE gene polymorphism plays a central role in lipid metabolism and has recently been suggested to regulate inflammation. Our objective is to evaluate whether APOE polymorphism affects susceptibility to SLE. APOE genotyping was performed using ApoE StripAssay™ kit. Results indicated significantly higher frequencies of allele ε4 and genotype ε3/ε4 and lower frequencies of allele ε3 and genotype ε3/ε3 in SLE patients than controls. APOE ε2 allele was found in three patients, whereas it was absent in controls. The frequencies of allele ε4 and genotype ε3/ε4 were significantly higher in SLE patients with renal involvement and those of alleles ε2, ε4 and genotypes ε2/ε3, ε3/ε4 were higher in patients with neuropsychiatric symptoms. It is concluded that APOE allele ε4 is associated with susceptibility risk/clinical manifestations of SLE and ε2 may increase its severity while ε3 is protective for SLE in Saudis.

Sample stacking microemulsion electrokinetic capillary chromatography induced by reverse migrating pseudostationary phase for the quantification of phenobarbital and its p-hydroxyphenobarbital metabolite in rat urine.

For the first time, a capillary electrophoretic (CE) method with sample stacking induced by a reverse migrating pseudostationary phase (SRMP) technique has been developed and validated for sensitive determination of phenobarbital (PB) and its p-hydroxyphenobarbital (PHPB) metabolite in rat urine samples. Separation and determination were optimized on a fused-silica capillary with a total length of 50 cm (effective length 40 cm) and 75 µm ID. The microemulsion background electrolyte consisted of 0.8% (v/v) ethyl acetate, 6.6% (v/v) butan-2-ol, 1.0% (v/v) acetonitrile, 2.0% (w/v) sodium n-dodecyl sulfate (SDS), and 89.6% (v/v) of 7.5 mM ammonium formate at pH 8. When this preconcentration technique was used, the sample stacking and the separation processes took place successively with changing the voltage with an intermediate polarity switching step. For practical application, a solid-phase extraction (SPE), C(18) sorbent with n-hexane/ethyl acetate (1 : 1%, v/v) as the elution solvent was used for sample purification and concentration. The SPE method gave good extraction yields for all the analytes, with absolute recovery values of 96.9% and 99.1% for PB and PHPB, respectively. The regression equations for PB and PHPB showed excellent linearity over a concentration range of 55-1386 ng mL(-1) for PB and PHPB (r = 0.998). The developed microemulsion electrokinetic capillary chromatography (MEEKC) method for separation of the studied compounds with SRMP as the electrophoretic preconcentration technique allowed detection limits in urine samples at 16.8 ng mL(-1) for PB and PHPB which are 15-fold lower than the reported CE method in the literature. The precision results, expressed by the intra-day and inter-day relative standard deviation (RSD) values range from 3.6 to 7.1% (repeatability) and from 3.2 to 7.2% (intermediate precision) for PB and PHPB, respectively, which were in line with Food and Drug Administration (FDA) criteria.

Novel, selective sample stacking microemulsion electrokinetic capillary chromatography induced by reverse migrating pseudostationary phase for the determination of the new ultra-short acting hypnotic "HIE-124" in mice serum.

Microemulsion electrokinetic capillary chromatography (MEEKC) with sample stacking induced by reverse migrating pseudostationary phase (SRMP) technique in a suppressed electro-osmotic flow (EOF) strategy was investigated for analysing the new ultra-short hypnotic HIE-124 in mice serum. The proposed method utilized fused-silica capillary with a total length of 50 cm (effective length 40 cm), applied voltages for stacking and separation were 5.0 kV for 4.30 min and subsequently 25 kV, respectively, with a sample injection of 0.5 psi for 90 s. All the runs were carried out at 25 degrees C and detected at 213 nm. The optimum microemulsion background electrolyte (BGE) solution consisted of 0.8% (v/v) ethyl acetate, 6.6% (v/v) butan-2-ol, 1.0% (v/v) acetonitrile, 2.0% (w/v) sodium dodecyl sulfate (SDS), and 89.6 mL with 25 mM phosphate buffer pH 8. When this preconcentration technique was used, the sample stacking and the separation processes took place successively with changing the voltage with an intermediate polarity switching step. The proposed method was validated carefully with respect to high specificity of the method, good linearity (r=0.9994), fair wide linear concentration range (66-1500 ng mL(-1)), limit of detection and quantitation were 21.6 and 65.5 ng mL(-1), respectively. The mean relative standard deviation (RSD) of the results of intra- and inter-day precision and accuracy were less than 6.0%, and overall recovery higher than 95% of HIE-124 in mice serum. The developed method could be used for the trace analyses of HIE-124 in serum and was finally used for the pharmacokinetic study investigation of HIE-124 in mice serum.

Rapid and sensitive simultaneous determination of ezetimibe and simvastatin from their combination drug products by monolithic silica high-performance liquid chromatographic column.

A simple, precise and rapid high-performance liquid chromatography (HPLC) method has been developed and validated for the simultaneous determination of ezetimibe (EZE) and simvastatin (SIM) from their combination drug products. The applicability of monolithic LC phases in the field of quantitative analysis has been evaluated. The existing method with UV detection set at 240 nm was successfully transferred from a conventional silica column to a 10 cm x 4.6 mm i.d. monolithic silica column. By simply increasing the mobile phase flow rate, run time was about five-fold reduced and the consumption of mobile phase was about two-fold decreased, while the chromatographic resolution of the analytes remain unaffected. Ranitidine (RAN) was used as internal standard to guarantee a high level of quantitative performance. The method used a mobile phase consisted of acetonitrile-ammonium acetate (50 mM pH 5.0) (65:35, v/v). It was validated with respect to system suitability, specificity, limit of quantitation (LOQ) and detection (LOD), linearity, precision, accuracy, and recovery, respectively. The described method was linear over the range of 40-1200 ng ml(-1) (r=0.999) for both drugs. The LOD for EZE and SIM were 13.2+/-0.4029 and 13.3+/-0.4772 ng ml(-1), respectively. The LOQ were found to be 39.9+/-1.221 and 39.5+/-1.446 ng ml(-1) for EZE and SIM, respectively. The method is fast (less than 2.0 min) and is suitable for high-throughput analysis of the drug and ones can analyze 700 samples per working day, facilitating the processing of large-number batch samples.