Multivariate optimization of mebeverine analysis using molecularly imprinted polymer electrochemical sensor based on silver nanoparticles

Thin film of a moleculary imprinted polymer (MIP) based on electropolymerization method with sensitive and selective binding sites for mebeverine (MEB) was developed. This film was cast on pencil graphite electrode (PGE) by electrochemical polymerization in solution of pyrrole (PY) and template MEB via cyclic voltammetry scans and further electrodeposition of silver nanoparticles (AgNPs). Several parameters controlling the performance of the silver nano particles MIP pencil graphite electrode (AgNPs-MIP-PGE) including concentration of PY(mM) concentration of mebeverine (mM), number of cycles in electropolymerization, scan rate of CV process (mV. s⁻¹), deposition time of AgNPs on to the MIP surface (s), stirring rate of loading solution (rpm), electrode loading time (min), pH of Britton–Robinson Buffer (BRB) solution were examined and optimized using multivariate optimization methods such as Plackett–Burman design (PBD) and central composite design (CCD). Two dynamic linear ranges of concentration for the MIP sensor were obtained as. 1 × 10⁻⁸ to 1 × 10⁻⁶ and 1 × 10⁻⁵ to 1 × 10⁻³ M with the limit of detection (LOD) of 8.6 × 10⁻⁹ M (S/N = 3). The proposed method was successfully intended for the determination of MEB in real samples (serum, capsule). The sensor was showed highly reproducible response (RSD 1.1%) to MEB concentration.     

抗胆碱能药物分子印迹聚合物的液相色谱行为

目的:以三种抗胆碱能药物为模板,合成分子印迹聚合物(molecularly imprinted polymer,MIP),考察不同流动相系统中MIP对于待测物的色谱分离行为及识别机理。方法:以盐酸新托品、盐酸苯环壬酯和盐酸戊乙奎醚为模板分子,甲基丙烯酸为功能单体,三羟甲基丙烷三甲基丙烯酸酯为交联剂,在乙腈中合成MIP,研磨后填装液相色谱柱,分别在有机溶剂流动相(乙酸-乙腈)和极性介质流动相(乙酸铵-乙腈)中考察MIP对盐酸新托品、盐酸苯环壬酯和盐酸戊乙奎醚的色谱分离行为。结果:在有机溶剂流动相中,各MIP对待测物均表现出强吸附;在极性介质流动相中,三种抗胆碱能药物的保留时间为t盐酸苯环壬酯相似文献   

Chiral separation of methoxamine and lobeline in capillary zone electrophoresis using ethylbenzene-deactivated fused-silica capillary columns and cyclodextrins as buffer additives

The complete chiral separation of methoxamine and lobeline was achieved by capillary zone electrophoresis on an ethylbenzene-deactivated fused-silica capillary column and with cyclodextrins (CDs) as buffer additives. Among the CDs investigated in this study, i.e. -CD, β-CD, dimethyl-β-CD, hydroxypropyl-β-CD and γ-CD, all the three β-type CDs showed chiral recognition on the two drugs investigated. Under the investigated conditions, the baseline chiral separation of methoxamine can be achieved with 90 mM Tris–H₃PO₄ (pH 2.5) containing 11.5 mM of the three β-type CDs, with dimethyl-β-CD giving the best resolution, whereas the baseline chiral separation of lobeline can be realized by using 90 mM Tris–H₃PO₄ buffer (pH 2.5) containing 5.8 mM dimethyl-β-CD or 29.5 mM hydroxypropyl-β-CD.     

Application of HPLC for the simultaneous determination of aceclofenac, paracetamol and tramadol hydrochloride in pharmaceutical dosage form

A simple, precise and accurate reversed-phase liquid chromatographic method has been developed for the simultaneous estimation of aceclofenac (ACF), paracetamol (PCM) and tramadol hydrochloride (TRM) in pharmaceutical dosage form. The chromatographic separation was achieved on a HiQ-Sil™ HS C18 column (250×4.6 mm i.d., 5 μm particle size), kromatek analytical column at ambient temperature. The mobile phase consisted of 40: 60 (v/v); phosphate buffer (pH 6.0): methanol. The flow rate was set to 1.0 mL min⁻¹ and UV detection was carried out at 270 nm. The retention time (t_R) for ACF, PCM and TRM were found to be 14.567 ± 0.02, 3.133 ± 0.01 and 7.858 ± 0.02 min, respectively. The validation of the proposed method was carried out for linearity, precision, robustness, limit of detection, limit of quantitation, speci city, accuracy and system suitability. The linear dynamic ranges were from 40–160 μg mL⁻¹ for ACF, 130–520 μg mL⁻¹ for PCM and 15–60 μg mL⁻¹ for TRM. The developed method can be used for routine quality control analysis of titled drugs in pharmaceutical dosage form.     

齐拉西酮分子印迹聚合物的制备及其识别特性

目的 用分子印迹技术制备以齐拉西酮为模板分子的分子印迹聚合物(MIP),并检测齐拉西酮在体内的含量.方法 以齐拉西酮为模板分子、甲基丙烯酸为功能单体、乙二醇甲基丙烯酸乙酯为交联剂,按模板分子-功能单体(1:4)制备齐拉西酮一甲基丙烯酸MIP.在底物为齐拉西酮溶液中放入MIP,于25℃中震荡12 h后,取上清液检测吸光度,计算相应吸附量.结果 齐拉西酮-甲基丙烯酸MIP对齐拉西酮溶液有一定的特异性吸附.结论 齐拉西酮-甲基丙烯酸MIP可以检测齐拉西酮的含量.     

Determination of metoprolol enantiomers in human urine by coupled achiral-chiral chromatography

Achiral chiral column switching HPLC assay was developed to allow the separation and quantitation of the enantiomers of metoprolol in human urine by means of fluorescence detection. Urine samples were prepared by liquid liquid extraction, followed by HPLC. The racemic metoprolol and internal standard were separated from the interfering components in urine and quantified on the silica column, and the enantiomers were determined on a Chiralcel OD chiral stationary phase. The two columns were connected by a switching valve equipped with a silica trap column. Detection limit was 25 ng/ml for each enantiomer. The intra-day variation ranged between 0.38 and 4.94% in relation to the measured concentration and the inter-day variation was 0.15-3.13%. It has been applied to the determination of (R)-(+)-metoprolol and (S)-(-)-metoprolol in urine from healthy volunteers dosed with racemic metoprolol tartrate.     

Chiral separation of the enantiomers of metoprolol and its metabolites by high performance liquid chromatography

(1'R, 2R)-, (1'R, 2S)-, (1'S, 2R)- and (1'S, 2S)-alpha-hydroxymetoprolol; (2R)- and (2S)-O-desmethylmetoprolol; and (2R)- and (2S)-metoprolol acid are major metabolites of (2R)-and (2S)-metoprolol, beta-adrenergic antagonist. The focus of most chiral separation methods until now has been on determination of the enantiomeric parent drug. However, it is just as important to be able to follow the metabolism of the enantiomers and their possible chiral metabolites. Therefore, for the study of stereoselective metabolism and pharmacokinetics of metoprolol, the chiral separation of the enantiomers of metoprolol and its metabolites has been investigated using four chiral stationary phases, i.e., Chiralcel OD, Chiral-AGP, Cyclobond I and Sumichiral OA-4900 columns. Metoprolol acid was resolved only by Sumichiral OA-4900. Chiralcel OD provided the highest separation factor and resolution value for metoprolol and O-desmethylmetoprolol and partially resolved the four stereoisomers of alpha-hydroxymetoprolol. Diastereomeric alpha-hydroxymetoprolols were resolved using the coupled column chromatographic system of two chiral stationary phases, Sumichiral OA-4900 column and Chiralcel OD column.     

罗红霉素分子印迹聚合物的合成及其特性研究

目的探讨采用分子印迹技术合成罗红霉素分子印迹聚合物的方法,并对其特性进行研究。方法以罗红霉素为模板分子,α-甲基丙烯酸为功能单体,以乙二醇二甲基丙烯酸酯为交联剂,采用分子印迹技术合成分子印迹聚合物。通过特异性吸附实验研究分子印迹聚合物的特性。结果通过静态平衡吸附法研究了模板聚合物的结合动力学以及该聚合物的结合能力和选择特性,通过Scatchard分析法研究了印迹聚合物对模板分子的结合特性,经计算聚合物的最大表观结合量（Qmax）和平衡离解常数（Kd）分别为90.3 mg.g^-1和1.35 mg.mL^-1。结论合成的分子印迹聚合物有形状、大小以及识别位点都与模板分子相匹配的空穴,即具有印迹作用。     

Design and characterization of propolis extract loaded self-nano emulsifying drug delivery system as immunostimulant

This current study aims to optimize, characterize, and observe the stability of the self-nano emulsifying drug delivery system (SNEDDS) of propolis extract (PE) for improving the immune response. Optimization of the selected composition of SNEDDS was conducted using a D-optimal mixture design. SNEDDS was prepared by loading 150 mg/mL of PE in oil, surfactant, and cosurfactant phases. The thermodynamic stability test was carried out with phase separation parameters followed by the robustness to dilution and accelerated stability test. The immunostimulant activity was examined in vitro and in vivo by determining the phagocytic activity, cell proliferation, production of nitrite oxide levels of RAW 264.7 cells, phagocytic activity of macrophages, and the number of leukocytes, neutrophils, and lymphocytes. The formula optimization showed that the formula containing Capryol-90, Cremophor RH40, and PEG 400 at a ratio of 30: 34: 36 was optimum. The verification response of the optimum formula with drug loading showed that the transmittance, droplet size, and zeta potential were 96.90 ± 0.00%, 28.7 ± 1.20 nm, and −56.5 ± 2.05 mV, respectively. The thermodynamic stability test and robustness to dilution did not find any separation phase. The accelerated stability test results were classified as stable. The in vitro and in vivo immunostimulant activity test showed that PE-loaded SNEDDS exhibited a higher immunostimulant effect than PE. In conclusion, the optimum and stable composition of PE loaded SNEDDS was found with a simple and accurate method using the D-Optimal mixture design and demonstrated an immunostimulant activity.     

（-）Doxazosin is a necessary component for the hypotensive effect of （±）doxazosin during long-term administration in conscious rats

Aim： Doxazosin is a racemic mixture of （–）doxazosin and （＋）doxazosin that is currently used as an add-on therapy for hypertension. In this study we investigated the contribution of each enantiomer to the hypotensive action of long-term administration of （±）doxazosin in conscious rats.
Methods： Blood pressure of conscious SD rats was measured using a volume pressure recording system. The rats were orally administered （–）doxazosin, （＋）doxazosin, or （±）doxazosin （8 mg·kg-1·d-1） for 12 weeks. Plasma concentrations of the agents were analyzed with HPLC. The effect of the agents on α1-adrenoceptor was examined in isolated rat caudal artery preparations.

Results： Treatment of conscious rats with a single dose of （±）doxazosin （8 mg/kg） did not affected DBP and MBP, but significantly decreased SBP by 11.9% 4 h after the administration. Long-term treatment of conscious rats with （±）doxazosin significantly decreased SBP, DBP and MBP with a maximal decrease of SBP by 29.3% 8 h after the last administration. The rank order of the hypotensive actions caused by long-term treatment in conscious rats was （±）doxazosin〉（＋）doxazosin〉〉（–）doxazosin. However, the pKB values for inhibiting NA-induced contraction of isolated rat caudal artery were （＋）doxazosin （8.995）〉（±）doxazosin （8.694）〉（–）doxazosin （8.032）. The plasma concentrations of （–）doxazosin, （＋）doxazosin, and （±）doxazosin were 18.26±3.55, 177.11±20.66, and 113.18±13.21 ng/mL, respectively, 8 h after the last administration of these agents.

Conclusion： Long-term treatment with （±）doxazosin produces potent hypotensive action in conscious rats that seems to result from synergic interaction of the two enantiomers.     

Comparison of the effects of clonidine on tyramine- and methoxamine-evoked mydriasis in man

1 It has been reported previously that clonidine can potentiate tyramine-evoked mydriasis on the pain-free side of cluster headache patients. We examined whether a single oral dose of clonidine (200 μg) can also potentiate tyramine-evoked mydriasis in healthy subjects, using mydriasis to methoxamine, a directly acting sympathomimetic amine, as a control. 2 Eight healthy male volunteers participated in four weekly sessions. In the first two sessions (Experiment 1) the effect of clonidine or placebo on the mydriasis to tyramine hydrochloride eyedrops (75 mm; 2×10 μl), and in the last two sessions (Experiment 2) the effect of clonidine or placebo on the mydriasis to methoxamine hydrochloride eyedrops (20 mm; 2×10 μl) was examined. In both experiments subjects were allocated to drugs and sessions according to a double-blind balanced design. In both experiments, pupil diameter of both the treated and the untreated eyes was recorded in standard ambient light and in the dark, before, and 2 h after clonidine/placebo, via binocular infrared television pupillometry. Salivation (dental roll technique), systolic and diastolic blood pressure (sitting), heart rate, and self-ratings of mood and feelings (visual analogue scales), were also measured before, and 2 h after the ingestion of clonidine or placebo. 3 Both tyramine and methoxamine produced a significant mydriasis, which was more prominent in the light condition (change in resting pupil size; mm±s.e.mean: tyramine/light 1.05±0.28; tyramine/dark: 0.73±0.15; methoxamine/light: 1.65±0.28; methoxamine/dark: 0.85±0.15). Clonidine produced a significant miosis in the untreated eye which was more prominent in the light condition (change in resting pupil size; mm±s.e.mean: Experiment 1, light: −1.34±0.19; Experiment 1, dark: −0.46±0.1; Experiment 2, light −0.97±0.18; Experiment 2, dark: −0.29±0.17). Clonidine had no significant effect on either tyramine- or methoxamine-evoked mydriasis. 4 In agreement with previous reports, clonidine significantly reduced salivation (g, mean±s.e.mean; Experiment 1: −0.84±0.22; Experiment 2: −0.55±0.11), systolic blood pressure (mm Hg; Experiment 1: −17.5±3.76; Experiment 2: −23.38±4.67), diastolic blood pressure (mm Hg; Experiment 2: −12.38±2.05), alertness (mm; Experiment 2: −24.19±5.40), and anxiety (mm; Experiment 1: −13.82±4.60), indicating the presence of pharmacodynamically effective tissue levels of the drug. 5 These results show that a single oral dose (200 μg) of clonidine causes significant miosis in human subjects, and fails to potentiate tyramine-evoked mydriasis. This indicates that the pupil on the asymptomatic side of cluster headache patients is affected differently from the pupils of healthy volunteers by tyramine and/or clonidine.     

Pharmacokinetics and response of obese patients with chronic hepatitis C treated with different doses of PEG-IFN α-2a (40KD) (PEGASYS®)

AIMS

To evaluate whether higher doses of peginterferon α-2a (40KD) [PEG-IFN α-2a (40KD)] can compensate for lower exposure observed among obese patients with chronic hepatitis C (CHC) treated with the standard dose of PEG-IFN α-2a (40KD).

METHODS

Noncirrhotic, obese (body mass index ≥30 kg m⁻²) patients with CHC participated in a single-centre, open-label study. Patients were randomized to 180 or 270 µg week⁻¹ PEG-IFN α-2a (40KD) + ribavirin (1000/1200 mg day⁻¹) for 48 weeks. Blood samples were collected predose and up to 168 h after the first dose and at week 12 for pharmacokinetic analysis. Trough serum concentrations (C_trough) were determined up to week 24.

RESULTS

In the 180 µg week⁻¹ group mean ± SD steady-state (week 12) estimates of AUC_0–168 (ng h⁻¹ ml⁻¹), C_max (ng ml⁻¹) and CL/F (l h⁻¹) were 2154 ± 919, 13.8 ± 6.7 and 0.102 ± 0.051, respectively. In the 270 µg week⁻¹ group, estimates were 3374 ± 1844, 23.4 ± 10.7 and 0.090 ± 0.042, respectively. The mean (range) C_trough (ng ml⁻¹) was 11.2 (4.4–18.5) in the 180 µg week⁻¹ group and 16.1 (0.4–44.2) in the 270 µg week⁻¹ group. Overall, 14 of 20 (70%) and 16 of 20 (80%) patients in the 180 µg week⁻¹ and 270 µg week⁻¹ groups were infected with hepatitis C virus genotype 1 or 4. In the 180 µg week⁻¹ and 270 µg week⁻¹ groups 14 of 20 (70%) and 15 of 19 (79%) patients, respectively, achieved a sustained viral response. Safety was similar between groups.

CONCLUSIONS

Mean PEG-IFN α-2a (40KD) exposure was dose proportional from 180 to 270 µg week⁻¹. Increasing PEG-IFN α-2a (40KD) from 180 to 270 µg week⁻¹ achieves higher serum drug exposure in obese patients.     

Primary afferents with TRPM8 and TRPA1 profiles target distinct subpopulations of rat superficial dorsal horn neurones

Background and purpose:

The transient receptor potential (TRP) channels, transient receptor potential melastatin-1 (TRPM8) and transient receptor potential ankyrin-1 (TRPA1), are expressed in subpopulations of sensory neurones and have been proposed to mediate innocuous and noxious cold sensation respectively. The aim of this study was to compare TRPM8 and TRPA1 modulation of glutamatergic afferent transmission within the spinal dorsal horn.

Experimental approach:

Whole cell patch clamp recordings were made from rat spinal cord slices in vitro to examine the effect of TRP agonists and temperature on glutamatergic excitatory postsynaptic currents (EPSCs).

Key results:

Icilin (3 or 100 µmol·L⁻¹), menthol (200 µmol·L⁻¹) and capsaicin (1 µmol·L⁻¹) reduced the amplitude of primary afferent evoked EPSCs in subpopulations of lamina I and II neurones. In a subpopulation of superficial neurones, innocuous cold (threshold 29°C), 3 µmol·L⁻¹ icilin (EC₅₀ 1.5 µmol·L⁻¹) and menthol (EC₅₀ 263 µmol·L⁻¹) increased the rate of spontaneous miniature EPSCs. In the majority of lamina I and II neurones, 100 µmol·L⁻¹ icilin (EC₅₀ 79 µmol·L⁻¹), allyl isothiocyanate (EC₅₀ 226 µmol·L⁻¹), cinnamaldehyde (EC₅₀ 38 µmol·L⁻¹) and capsaicin (1 µmol·L⁻¹) increased miniature EPSC rate. The response to 100 µmol·L⁻¹, but not 3 µmol·L⁻¹ icilin, was abolished by ruthenium red, while neither was affected by iodoresiniferatoxin. Responsiveness to 3 µmol·L⁻¹, but not to 100 µmol·L⁻¹ icilin, was highly predictive of innocuous cold responsiveness. Neurones responding to 3 µmol·L⁻¹ icilin and innocuous cold were located more superficially than those responding to 100 µmol·L⁻¹ icilin.

Conclusions and implications:

Activation of TRPM8 and TRPA1 presynaptically modulated glutamatergic transmission onto partially overlapping but distinct populations of superficial dorsal horn neurones. Spinal TRPM8 and TRPA1 channels may therefore provide therapeutic targets in cold hyperesthesia.     

分子印迹聚合物在药物分析中的应用

简要介绍分子印迹聚合物(MIP)的制备过程，并利用MIP对药物分子特殊的选择性和识别能力，广泛应用于药物分析以及手性药物的分离、富集和提纯。重点综述MIP技术在药物分析方面的应用。     

Method transfer for fast liquid chromatography in pharmaceutical analysis: application to short columns packed with small particle. Part I: isocratic separation.

Liquid chromatography (LC) is considered to be the gold standard in pharmaceutical analysis. Today, there is a need for fast and ultra-fast methods with good efficiency and resolution for achieving separations in few minutes or even seconds. The present work describes a simple methodology for performing a successful method transfer from conventional LC to fast and ultra-fast LC. In order to carry out fast separations, short columns (20-50mm) packed with small particles (3.5 and 1.7 microm) were used and their chromatographic performance was compared to that of a conventional column (150 mm, 5 microm). For that purpose, an optimized LC system was employed to limit extra-column volumes which can have a dramatic impact on efficiency and resolution. This paper reports the fundamental equations used for transferring an isocratic chromatographic separation performed with a given column geometry and chemistry to a smaller column packed with similar or identical stationary phase, without influence on chromatographic performance. For this purpose, the flow rate and the injected volume need to be adapted. The effect of column length and particle size reduction on chromatographic resolution and analysis time was described for an isocratic separation. Using the method transfer equations, it is possible to predict the new conditions to be used, for fast and ultra-fast separations. In this work, ultra-fast separations were achieved thanks to a new generation of instrumentation (ultra performance liquid chromatography, UPLC) which uses simultaneously short column packed with sub-2 microm particles and ultra-high pressure (up to 1000 bar). This work demonstrates an analysis time reduction up to a factor 12, compared to a conventional LC separation, without affecting the quality of separation. Therefore, the complete resolution of a pharmaceutical formulation was achieved in only a few seconds.     

Efficacy and pharmacokinetics of a new intrarectal quinine formulation in children with Plasmodium falciparum malaria

1Three groups of seven children aged 2–14 years with acute uncomplicated Plasmodium falciparum malaria received 12.8 mg kg⁻¹ quinine gluconate by the intrarectal route (new cream formulation) or 8 mg kg⁻¹ Quinimax (a Cinchona alkaloid combination) by the intramuscular or intravenous (4 h infusion) route every 8 h for 3 days. Clinical and parasitological status was similar in the three groups at enrolment. 2At 36 h, body temperature of all children of the three groups was returned to normal and remained so until day 7. 3The decrease in parasitaemia did not differ between the three groups and the time required for a 50% fall in parasitaemia relative to baseline was 12.3±5.4, 18.2±6.1 and 14.5±4.2 h in the intrarectal, intramuscular and intravenous treatment groups, respectively. Parasitaemia expressed as a percentage of initial values was not significantly different in the three groups after 48 h of treatment (7.4±16.0, 4.1±4.2 and 2.2±3.8% in the intrarectal, intramuscular and intravenous treatment groups, respectively). All the patients were aparasitaemic by day 7. 4The tolerability of the three treatments was good; in particular, no rectal irritation was reported with the cream formulation. 5The t_max occurred later after intrarectal (4.1±2.4 h) and intravenous infusion (3.8±0.5 h) than after intramuscular injection (1.6±1.3 h) (P=0.02). C_max was lower with the intrarectal (3.0±1.0 mg l⁻¹) and intramuscular routes (3.2±0.7 mg l⁻¹) than with the intravenous route (5.1±1.4 mg l⁻¹) (P=0.003). Areas under the curve (AUC(0, 8 h)) were smaller with the intrarectal (17.0±7 mg l⁻¹ h) and intramuscular routes (19.4±4.8 mg l⁻¹ h) than with the intravenous route (27.8±8.2 mg l⁻¹ h) (P=0.02). The approximate bioavailability of intrarectal quinine from 0 to 8 h was 36%vs intravenous quinine and 51%vs intramuscular quinine. 6The good tolerability and efficacy of this new intrarectal quinine formulation outweigh its low approximate bioavailability. This new approach might thus be a safe and effective alternative to intramuscular quinine injection for the treatment of children with acute uncomplicated Plasmodium falciparum malaria in the field.     

Separation of the S(+) and R(−)-enantiomers of tiagabine·HCl and its two chiral precursors by chiral chromatography: application to chiral inversion studies

Chiral HPLC methods were developed and validated for tiagabine·HCl and its two chiral precursors to determine the chiral purity of the three compounds to ensure the quality of the final product which is used as a new antiepileptic drug. Tiagabine·HCl was derivatized with 1-napthalenemethylamine and was chromatographed on a Pirkle type phenyl glycine column with a mobile phase of 69:31, 0.1 M ammonium acetateacetonitrile (v/v). The two chiral precursors were chromatographed on a Chiralcel-OG column with a mobile phase of hexane, isopropanol etc. Each of the three HPLC methods have a selectivity factor () of 1–2 or higher. The validation of the methods was done by conducting standard addition and recovery studies of the S(+)-enantiomers in the samples. The %RSD of all three methods were <5 with a limit of quantification of 0.05% (peak area) or lower. By using these methods, a study was conducted to investigate the effect of pH, temperature, and trace levels of transition metals such as Fe³⁺, Co²⁺, and Ni²⁺ on the conversion of R(−)-enantiomer to the S(+)-enantiomer of tiagabine·HCl and its two chiral precursors. The results of this study demonstrated that the two chiral precursors of tiagabine·HCl under reflux conditions are more sensitive to chiral inversion than tiagabine·HCl. Under reflux conditions, in the presence of trace metal ions and different pH, approximately 10, 11, and 1% of the R(−)-enantiomer was converted to the S(+)-enantiomer for ethyl nipecotate, ethylester of tiagabine, and tiagabine·HCl, respectively. However, at room temperature, tiagabine·HCl appears to be less chirally stable than its two chiral precursors. Approximately 0.4% R(−)-enantiomer of tiagabine·HCl was converted to the S(+)-enantiomer at room temperature and acidic conditions. Under similar conditions, the S(+)-enantiomer of ethyl nipecotate and ethylester of tiagabine·HCl was <0.05%. The initial S(+)-enantiomer content for all three compounds was <0.1%.     

HPLC enantioseparation of potential beta-blockers of the aryloxyaminopropanol type. Study of the mechanism of enantioseparation, Part VIII

This paper presents the results of HPLC enantioseparation of derivatives of aryloxyaminopropanols obtained using six chiral stationary phases [macrocyclic antibiotic (vancomycin, teicoplanin, teicoplanin aglycone, and methylated teicoplanin aglycone) and cyclodextrin (beta and gamma)] and a mixture of methanol/acetonitrile/acetic acid/triethylamine (45/55/0.3/0.2) as the mobile phase. No significant difference was observed in the separation of the enantiomers on the vancomycin and teicoplanin chiral stationary phases. Comparing the separation of enantiomers on teicoplanin-based columns the retention factors were increased in the order: native teicoplanin < teicoplanin aglycone < methylated teicoplanin aglycone. The highest values of resolution were obtained on the column containing carbohydrate moieties. The presence of saccharide moieties in the chiral stationary phase plays an important role, together with charge interactions and steric interactions, in the separation of enantiomers of derivatives of aryloxyaminopropanol.     

Evodiamine improves congnitive abilities in SAMP8 and APP(swe)/PS1(ΔE9) transgenic mouse models of Alzheimer's disease

Aim:

To investigate the effect of evodiamine (a quinolone alkaloid from the fruit of Evodia rutaecarpa) on the progression of Alzheimer''s disease in SAMP8 and APP^swe/PS1^ΔE9 transgenic mouse models.

Methods:

The mice at age of 5 months were randomized into the model group, two evodiamine (50 mg·kg⁻¹·d⁻¹ and 100 mg·kg⁻¹·d⁻¹) groups and an Aricept (2 mg·kg⁻¹·d⁻¹) group. The littermates of no-transgenic mice and senescence accelerated mouse/resistance 1 mice (SAMR1) were used as controls. After 4 weeks of treatment, learning abilities and memory were assessed using Morris water-maze test, and glucose uptake by the brain was detected using positron emission tomography/computed tomography (PET/CT). Expression levels of IL-1β, IL-6, and TNF-α in brain tissues were detected using ELISA. Expression of COX-2 protein was determined using Western blot.

Results:

In Morris water-maze test, evodiamine (100 mg·kg⁻¹·d⁻¹) significantly alleviated the impairments of learning ability and memory. Evodiamine (100 mg·kg⁻¹·d⁻¹) also reversed the inhibition of glucose uptake due to development of Alzheimer''s disease traits in mice. Furthermore, the dose of evodiamine significantly decreased the expression of IL-1β, IL-6, TNF-α, and COX-2 that were involved in the inflammation due to Alzheimer''s disease.

Conclusion:

The results indicate that evodiamine (100 mg·kg⁻¹·d⁻¹) improves cognitive abilities in the transgenic models of Alzheimer''s disease.     

Combination of methotrexate and sulphasalazine in patients with rheumatoid arthritis: pharmacokinetic analysis and relationship to clinical response

1. The influence of sulphasalazine (SASP) on the pharmacokinetics of low dose methotrexate (MTX) and the relation between pharmacokinetic variables and clinical response was studied in 15 patients with active rheumatoid arthritis despite >6 months of SASP treatment.
2. SASP was stopped for 2 weeks. Thereafter a single oral dose of 7.5 mg MTX was administered after a standard breakfast. Blood was sampled initially every 30 min, thereafter hourly during 8 h. Urine was sampled every hour. Then 2000 mg SASP daily + 7.5 mg MTX weekly was given. After 4 weeks the same procedure was repeated supplemented with concomitant administration of 1000 mg SASP. Clinical measurements included Ritchie articular index, number of swollen joints, ESR and the disease activity score. Pharmacokinetic analysis was performed using a two- compartment model with first order absorption and lag time. Results are given as mean (s.d.). Paired t-test or signed rank test were applied in the statistical analysis.
3. Pharmacokinetics of MTX without vs with SASP, means±s.d. were as follows: AUC: 673±179 vs 628±210 (95% confidence interval [CI] of the difference was −71 to 159) ng ml⁻¹ h, MRT: 5.2±1.3 vs 5.2±1.1 (95% CI −0.4 to 0.4) h, t½,z: 4.3±1.1 vs 4.2±1.1 (95% CI −0.3 to 0.5) h, V /F: 59.3 ±29.3 vs 65.5±25.3 (95% -23.8 to 11.4) l, CL/F: 12.3±5.0 vs 13.5±4.8 (95% CI −4.5 to 2.3) l h⁻¹. CL_R/F: 6.2±1.3 vs 6.3±2.1 (95% CI −1.3 to 1.1) l h⁻¹. All P values were ≥0.3.
4. A weak correlation existed between the change of ESR and the MRT, the t½,z and the V /F (Spearman correlation coefficients of 0.43, 0.50 and 0.50 respectively, 0.05<P<0.1).
5. There is no significant influence of chronic SASP administration on the pharmacokinetics of MTX or vice versa. Of the clinical variables, only the ESR correlated consistently with some pharmacokinetic variables of MTX.