OBJECTIVES: To evaluate the effects on the formation of benzidine-hemoglobin, and benzidine metabolite-hemoglobin adducts, caused by pretreatment with the known xenobiotic metabolism effectors, ethanol and phenobarbital, in rats administered Direct Black 38 dye. METHODS: The experimental rats were divided into three groups: a control group, an ethanol group and a phenobarbital group. Rats were pretreated with ethanol (1g/kg) or phenobarbital (80mg/kg) 24 hours prior to the oral administration of Direct Black 38 (0.5mmol/kg), with the control group being administered the same amount of distilled water. Blood samples were obtained from the vena cava of 5 rats from each group prior to, and at 30 min, 3 h, 6 h, 9 h, 12 h, 24 h, 48 h, 72 h, 96 h, and 144 h following the oral administration of Direct Black 38. Directly after sampling the blood was separated into hemoglobin and plasma, with the adducts being converted into aromatic amines by basic hydrolysis. Hydrolyzed benzidiene, monoacetylbenzidine and 4-aminobiphenyl were analyzed by reverse-phase liquid chromatography with an electrochemical detector. The quantitative amount of the metabolites was expressed by the hemoglobin binding index (HBI). RESULTS: In the ethanol group, benzidine-, monoacetylben-zidine-, and 4-aminobiphenyl-HBI were increased to a greater extent than those in the control group. These results were attributed to the ethanol inducing N-hydroxylation, which is related to the formation of the hemoglobin adduct. In the phenobarbital group, all the HBIs, with the exception of the benzidine-HBI, were increased to a greater extent than those of the control group. These results were attributed to the phenobarbital inducing N-hydroxylation related to the formation of the hemoglobin adduct. The N-acetylation ratio was only increased with the phenobarbital pretreatment due to the lower benzidine-HBI of the phenobarbital group compared to those of the control and ethanol groups. The N-acetylation ratios for all groups were higher than 1 for the duration of the experimental period. Although the azo reduction was unaffected by the ethanol, it was inhibited by the phenobarbital. The ratio of the benzidine-HBI in the phenobarbital group was lower than those of the ethanol the control groups for the entire experiment. CONCLUSION: Our results indicate that both ethanol and phenobarbital increase the formation of adducts by the induction of N-hydroxylation, but also induced N-acetylation. Phenobarbital decreased the formation of benzidine-HBI due to the decrease of the azo reduction. These results suggest that the effects of ethanol and phenobarbital need to be considered in the biochemical monitoring of Direct Black 38.
Administration, Oral ; Amines ; Animals ; Chromatography, Reverse-Phase ; Ethanol* ; Hydrolysis ; Metabolism ; Phenobarbital* ; Plasma ; Rats* ; Water

OBJECTIVES: The effects of ethanol and phenobarbital,which are known to affect metabolism of xenobiotics, on the formation of benzidine-and its metabolites-plasma protein adducts in rats administered benzidine were evaluated. METHODS: The experimental rats were divided into the control,ethanol and phenobar-bital groups. The experimental groups (ethanol and phenobarbital group)were pretreated with ethanol (1g/kg)or phenobarbital (80mg/kg)24 hours prior to the oral administration of benzidine (0.5mmol/kg). Blood samples were obtained from the vena cava from 5 rats in each group; and at 30 min,3 h,6 h,9 h,12 h,24 h,48 h,72 h,96 h,and 144 h after the administration of benzidine using heparin treated syringes.The plasma protein levels were separated immediately after taking blood samples. The adducts were underwent basic hydrolysis to convert them into aromatic amines. The hydrolyzed benzidine, monoacetylbenzidine, and 4-aminobiphenyl were analyzed by reverse-phased liquid chro-matography with an electrochemical detector. The quantitative amount of the metabolites was expressed by the plasma protein binding index(PBI). RESULTS: Similar to the hemoglobin adducts,the levels of the plasma protein adducts of the ethanol and phenobarbital groups (benzidine-, monoacetylbenzidine-, and 4-amino-biphenyl-PBI)were higher than those of the control group. These results are attributable to the fact that ethanol and phenobarbital induced to the plasma protein adduct formation. The N-acetylation ratio in the control group was highest at 72 h with 2.34.In the ethanol group,it was highest at 72 h with a ratio of 2.46 and was highest in the phenobarbital group at 72 h with a ratio of 2.43. The N-acetylation ratio of the plasma protein adducts was relatively lower than that of the hemoglobin adducts.The level of the plasma protein adduct increased more rapidly than the hemoglobin adducts in all experimental groups regardless of the pretreatment,and decreased rapidly after reaching the maximum level. CONCLUSION: The above results indicate that ethanol and phenobarbital increased the level of plasma protein adduct formation. The plasma protein adducts tended to decrease more rapidly than the hemoglobin adducts in the body after benzidine exposure. This results in this study result suggests that the effects of ethanol or phenobarbital need to be considered in the biochemical monitoring,and that the level of the plasma protein adducts be a more proper biomarker than the hemoglobin adducts for assessing the short term exposure to a benzidine and benzidine based dye.
Administration, Oral ; Amines ; Animals ; Environmental Monitoring* ; Ethanol* ; Heparin ; Hydrolysis ; Metabolism ; Phenobarbital* ; Plasma* ; Protein Binding ; Rats* ; Xenobiotics

BACKGROUND: Gabapentin is a safe and well-tolerated anticonvulsant with a wide therapeutic index, and it is used for neuropathic pain. The aim of this study was to compare previous dosing methods with the administration of four different doses of gabapentin while maintaining the same maximum daily dose for the safe administration of high doses of the medication. METHODS: The subjects were outpatients with various neuropathic pain syndromes, with at least two of the following symptoms: allodynia, burning pain, shooting pain, or hyperalgesia. The TID group received equal doses of gabapentin 3 times per day, while the QID group received 4 different doses of gabapentin per day. The pain score, frequency of breakthrough pain (BTP), severity and the duration of pain, sleep disturbance due to nocturnal pain, and adverse effects were recorded each day. RESULTS: The average daily pain score and sleep disturbance were significantly reduced in the QID group between days 3 and 10 of the experiment. The adverse effects of the medication were also reduced in the QID group. However, the frequency of BTP and severity and duration of pain were not significantly different between two groups. CONCLUSIONS: Administration of 4 different doses of gabapentin during the initial titration in outpatients with neuropathic pain resulted in a significant reduction in awakening from breakthrough pain and a reduction in the adverse effects of the medication.
Ambulatory Care ; Amines ; Breakthrough Pain ; Burns ; Cyclohexanecarboxylic Acids ; Drug Administration Schedule ; gamma-Aminobutyric Acid ; Humans ; Hyperalgesia ; Neuralgia ; Outpatients

AIMTo investigate factors affecting the properties of antisense oligodeoxy nucleotides (ASON)-liposomes complex and their cellular uptake.

METHODSThree types of blank liposomes were prepared by reverse-phase evaporation vesicles, and the complex were obtained through physical absorption. The light microscope was used to observe morphology characteristics of the complex. Drug loading capacity was analyzed by agarose gel electrophoresis. The transfected cell percentage and means fluorescence intensity were determined by flow cytometric analysis using M3 myeloma cell as a model.

RESULTSThe neutral liposome showed no aggregation while the cationic liposomes appeared some different extent aggregation in different medium when associated antisense oligodeoxynucleotides. The drug loading capacity depended on the ratio of +/- and the cationic charge density on the lipid membrane. The two kinds of cationic liposomes appeared different principles of loading ASON. As far as cellular uptake, The neutral liposomes showed no improvement of cellular uptake of ASON. However, the cationic liposomes were shown to enhance the cellular uptake of ASON if the appropriate +/- charge ratio was used. The optimal cellular uptake was achieved when +/- charge ratio was at 0.5:1 and 1:1 for SA-I liposome and SA-II liposomes, respectively.

CONCLUSIONThe cationic liposomes improved the loading capacity and cell uptake of antisense oligodeoxynucleotides, which was determined by +/- charge ratio and charge density.

Amines ; metabolism ; Biological Transport ; Drug Carriers ; Drug Delivery Systems ; Humans ; Liposomes ; pharmacokinetics ; Multiple Myeloma ; Oligodeoxyribonucleotides, Antisense ; administration & dosage ; pharmacokinetics ; Random Allocation ; Tumor Cells, Cultured ; metabolism

Herein, solid lipid nanoparticles (SLN) were proposed as a new drug delivery system for adefovir dipivoxil (ADV). The octadecylamine-fluorescein isothiocynate (ODA-FITC) was synthesized and used as a fluorescence maker to be incorporated into SLN to investigate the time-dependent cellular uptake of SLN by HepG2.2.15. The SLN of monostearin with ODA-FITC or ADV were prepared by solvent diffusion method in an aqueous system. About 15 wt% drug entrapment efficiency (EE) and 3 wt% drug loading (DL) could be reached in SLN loading ADV. Comparing with free ADV, the inhibitory effects of ADV loaded in SLN on hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg) and hepatitis B virus (HBV) DNA levels in vitro were significantly enhanced.
Adenine ; administration & dosage ; analogs & derivatives ; pharmacokinetics ; Amines ; Antiviral Agents ; administration & dosage ; pharmacokinetics ; Cell Line ; Drug Delivery Systems ; Fluorescein-5-isothiocyanate ; Fluorescent Dyes ; Glycerides ; Hepatitis B virus ; drug effects ; Humans ; Nanoparticles ; Nanotechnology ; Organophosphonates ; administration & dosage ; pharmacokinetics

Gabapentin decreases the level of glutamate and elevates that of garmma-amino-butyric acid in the central nervous system. Gabapentin was shown to have antinociceptive effects in several facilitated pain models. Intrathecal gabapentin was also known to be effective in reducing mechanical allodynia in animals with neuropathic pain. In this study, we investigated to see whether intrathecal gabapentin produces antihyperalgesic effects on thermal and mechanical hyperalgesia in neuropathic rats and whether its effects are associated with motor impairment. To induce neuropathic pain in Sprague-Dawley rats, left L5 and L6 spinal nerves were ligated. After a week, lumbar catheterization into subarachnoid space was performed. Then, paw withdrawal times to thermal stimuli and vocalization thresholds to paw pressure were determined before and up to 2 hr after intrathecal injection of gabapentin. Also, motor functions including performance times on rota-rod were determined. Intrathecal gabapentin attenuated significantly thermal and mechanical hyperalgesia in neuropathic rats, but did not block thermal and mechanical nociception in sham-operated rats. Intrathecal gabapentin of antihyperalgesic doses inhibited motor coordination performance without evident ambulatory dysfunction. This study demonstrates that intrathecal gabapentin is effective against thermal and mechanical hyperalgesia, in spite of moderate impairment of motor coordination.
Acetic Acids/administration & dosage/*pharmacology ; *Amines ; Analgesics/administration & dosage/*pharmacology ; Animals ; *Cyclohexanecarboxylic Acids ; Dose-Response Relationship, Drug ; Injections, Spinal ; Ligation ; Male ; Rats ; Rats, Sprague-Dawley ; Spinal Nerves/*injuries ; Time Factors ; *gamma-Aminobutyric Acid

Spinal gabapentin and adenosine have been known to display an antinociceptive effect. We evaluated the nature of the interaction between gabapentin and adenosine in formalin-induced nociception at the spinal level. Male Sprague-Dawley rats were prepared for intrathecal catheterization. Pain was evoked by injection of formalin solution (5%, 50 microliter) into the hindpaw. After examination of the effects of gabapentin and adenosine, the resulting interaction was investigated with isobolographic and fractional analyses. Neither gabapentin nor adenosine affected motor function. Gabapentin or adenosine decreased the sum of the number of flinches during phase 2, but not during phase 1 in the formalin test. Isobolographic analysis, in phase 2, revealed an additive interaction between gabapentin and adenosine. Taken together, intrathecal gabapentin and adenosine attenuated the facilitated state and interacted additively with each other.
*Adenosine/administration & dosage/metabolism/therapeutic use ; *Amines/administration & dosage/metabolism/therapeutic use ; *Analgesics/administration & dosage/metabolism/therapeutic use ; Animals ; *Cyclohexanecarboxylic Acids/administration & Dose-Response Relationship, Drug ; Formaldehyde/*toxicity ; Injections, Spinal ; Male ; Motor Activity/physiology ; Pain Measurement ; Rats ; Rats, Sprague-Dawley ; Research Support, Non-U.S. Gov't ; *gamma-Aminobutyric Acid/administration & dosage/metabolism/therapeutic

A sensitive, rapid and specific liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method for quantification of gabapentin in human plasma has been developed. After a single plasma protein precipitation with methanol, gabapentin and metformin (internal standard) were chromatographed on a Inertsil ODS-3 column (50 mm x 2.1 mm ID, 3 microm) with mobile phase consisting of methanol-0.2% formic acid aqueous solution (80:20, v/v) at a flow-rate of 0.2 mL x min(-1). Electrospray ionization (ESI) source was applied and operated in the positive ion mode. Multiple reaction monitoring (MRM) mode with the transitions of m/z 172 --> m/z 154 and m/z 130 --> m/z 71 were used to quantify gabapentin and metformin, respectively. The run time was 2.2 min. The linear calibration curve was obtained in the concentration range of 40.8-8.16x10(3) ng x mL(-1). The lower limit of quantification was 40.8 ng x mL(-1). The intra- and inter-day precision (RSD) was less than 12%, and the accuracy (RE) was within +/-6.4% calculated from quality control (QC) samples. The method was used to determine the concentration of gabapentin in human plasma after a single oral administration of 600 mg gabapentin capsule to 20 healthy male Chinese volunteers. The method was proved to be selective, sensitive, rapid and suitable for pharmacokinetic study of gabapentin in human plasma.
Administration, Oral ; Amines ; administration & dosage ; blood ; pharmacokinetics ; Anticonvulsants ; administration & dosage ; blood ; pharmacokinetics ; Area Under Curve ; Chromatography, High Pressure Liquid ; Cyclohexanecarboxylic Acids ; administration & dosage ; blood ; pharmacokinetics ; Humans ; Male ; Spectrometry, Mass, Electrospray Ionization ; Tandem Mass Spectrometry ; gamma-Aminobutyric Acid ; administration & dosage ; blood ; pharmacokinetics

OBJECTIVETo study the clinical effects of gabapentin on the treatment of pruritus of scar resulting from deep partial-thickness burn.

METHODSA total of fifty-eight patients suffering from pruritus of scar after deep partial-thickness burn were hospitalized from January 2013 to January 2014. Patients were divided into placebo group (n =18, treated with oral vitamin C in the dose of 100 mg for 4 weeks, twice per day) , cetirizine group (n = 20, treated with oral cetirizine in the dose of 10 mg for 4 weeks, twice per day) , and gabapentin group (n = 20, treated with oral gabapentin in the dose of 300 mg for 4 weeks, twice per day) . Before treatment and on post treatment day (PTD) 3 and 28, the Visual Analog Scale (VAS) was used to assess the itching degree, and the mean scores were recorded. The remission rates of pruritus on PTD 3 and 28 were calculated. The adverse effects were observed during treatment. Data were processed with analysis of variance, q test, and chi-square test.

RESULTSCompared with that before treatment, the itching degree of patients with light, moderate, and severe itching in placebo group was not relieved after treatment; the itching degree of patients with moderate or severe itching in cetirizine group was alleviated after treatment, but not in patients with light itching; itching degree of all patients in gabapentin group was significantly relieved after treatment. There were no obvious differences in VAS scores among the 3 groups before treatment (F = 2.78, P > 0.05). On PTD 3 and 28, the VAS scores of patients in both gabapentin group [(2.3 ± 0.8) and (0.6 ± 0.3) points] and cetirizine group [(4.2 ± 1.7) and (2.8 ± 1.2) points] were lower than those in placebo group [(5.7 ± 2.0) and (5.7 ± 1.9) points, with q values from 6.70 to 7.75, P values below 0.05]. The VAS scores of patients in gabapentin group on PTD 3 and 28 were lower than those in cetirizine group (with q values respectively 6.30 and 6.90, P values below 0.05). The remission rates of pruritus of patients in gabapentin group on PTD 3 and 28 were respectively (66 ± 20)% and (91 ± 17)%, and they were higher than those in cetirizine group [(33 ± 8)% and (56 ± 14)%, with q values respectively 4.70 and 3.82, P values below 0.05]. The remission rate of pruritus of patients in placebo group on PTD 3 and 28 was 0, which was lower than that of the other 2 groups each (with q values from 3.94 to 6.76, P values below 0.05). During the course of treatment, 5 patients in gabapentin group suffered from adverse effects including mild-to-moderate drowsiness and dizziness, but they disappeared one week later. No adverse effects were observed in patients of the other two groups.

CONCLUSIONSFor patients with deep partial-thickness burn, gabapentin can effectively alleviate scar itching after wound healing with safety.

Amines ; administration & dosage ; therapeutic use ; Analgesics ; therapeutic use ; Ascorbic Acid ; administration & dosage ; Burns ; complications ; Cetirizine ; administration & dosage ; Cicatrix ; Cyclohexanecarboxylic Acids ; administration & dosage ; therapeutic use ; Humans ; Pruritus ; drug therapy ; Skin Transplantation ; Treatment Outcome ; Visual Analog Scale ; Wound Healing ; gamma-Aminobutyric Acid ; administration & dosage ; therapeutic use

BACKGROUND: Experimental studies have shown that gabapentin can reduce neuronal injury in the setting of cerebral ischemia, but the mechanisms have not yet been clearly determined. This study was conducted to determine whether gabapentin pretreatment altered expression levels of heat shock protein 70 and reduced acute phase neuronal injury in rats subjected to transient focal cerebral ischemia/reperfusion. METHODS: Forty male Sprague-Dawley rats (260-300 g) were randomly assigned to one of four groups (saline-treated, or 0.1, 0.5, or 5 mg/kg gabapentin group). In all animals, focal cerebral ischemia was induced by intraluminal middle cerebral artery occlusion for 1 hour. The animals of the gabapentin groups were pretreated with a single intravenous administration of gabapentin 20 minutes before ischemic insults. The infarct volume, brain edema and motor behavior deficits were analyzed 24 hours after ischemic insult. Caspase-3-reactive cells and cells showing Hsp70 activity were counted in the caudoputamen and fronto-parietal cortex. RESULTS: The infarction ratio was significantly decreased in the 5 mg/kg gabapentin group (P < 0.05) and brain edema ratios were significantly reduced in the 0.1 mg/kg, 0.5 mg/kg, and 5 mg/kg gabapentin groups 24 hours after ischemia/reperfusion injury (P < 0.05). There were more Hsp70-reactive cells in the 5 mg/kg gabapentin group than in the saline group in both the caudoputamen and fronto-parietal cortex (P < 0.05). CONCLUSIONS: These results indicate that gabapentin may have a neuroprotective effect and can reduce early neuronal injury caused by focal cerebral ischemia/reperfusion; this may be mediated by expression of Hsp70. However, gabapentin pretreatment did not prevent caspase-dependent apoptosis.
Administration, Intravenous ; Amines ; Animals ; Apoptosis ; Brain ; Brain Edema ; Brain Injuries ; Brain Ischemia ; Caspase 3 ; Cyclohexanecarboxylic Acids ; gamma-Aminobutyric Acid ; HSP70 Heat-Shock Proteins ; Humans ; Infarction ; Infarction, Middle Cerebral Artery ; Male ; Neurons ; Neuroprotective Agents ; Rats ; Rats, Sprague-Dawley