OBJECTIVES: The hepatotoxicity of acetaminophen is not a result of the parent compound but is mediated by its reactive metabolite N-acetyl-p-benzoquinone imine. Cytochrome P4502E1 (CYP2E1) is the principal enzyme of this biotransformation, which accounts for approximately 52% of the bioactivation in human microsomes. Recently, chlormethiazole a sedative drug, is reported to be an efficient inhibitor of CYP2E1 activity in human beings. In this study we wished to evaluate whether chlormethiazole, an inhibitor of CYP2E1, could prevent acetaminophen-induced liver injury in mice. METHODS: Acetaminophen, at doses ranging from 200 to 600 mg/kg, was injected into the peritoneum of female C57BL/6 inbred mice fasted for four hours. Chlormethiazole (60 mg/kg) or 5% dextrose water was given 30 min before or 2 h after acetaminophen. Serum aminotransferase activities, histologic index score, survival rate and hepatic malondialdehyde levels were compared. RESULTS: Pretreatment with chlormethiazole 30 min before 400 mg/kg of acetaminophen completely inhibited acetaminophen-induced liver injury (median 118.5 U/L, range 75 to 142 vs. 14,070 U/L, range 5980 to 27,680 for AST; 49 U/L, range 41 to 64 vs. 15,330 U/L, range 13,920 to 15,940 for ALT). In mice receiving chlormethiazole 2 h after acetaminophen, the mean AST and ALT levels were also less elevated, reaching only 20% of the value of acetaminophen-only group. These protective effects were confirmed histologically. Whereas more than 50% of mice died at 500 mg/kg of acetaminophen, all the mice pretreated with chlormethiazole survived at the same dose. CONCLUSION: Chlormethiazole effectively reduces acetaminophen-induced liver injury in mice. Further studies are needed to assess its role in humans.
Acetaminophen/toxicity* ; Acetaminophen/metabolism ; Acetaminophen/antagonists & inhibitors ; Analgesics, Non-Narcotic/toxicity* ; Analgesics, Non-Narcotic/metabolism ; Analgesics, Non-Narcotic/antagonists & inhibitors ; Animal ; Chlormethiazole/pharmacology* ; Cytochrome P-450 CYP2E1/antagonists & inhibitors ; Enzyme Inhibitors/pharmacology ; Female ; Human ; Liver/metabolism ; Liver/injuries* ; Liver/drug effects* ; Mice ; Mice, Inbred C57BL ; Sedatives, Nonbarbiturate/pharmacology* ; Support, Non-U.S. Gov't

Large doses of acetaminophen (APAP) could cause oxidative stress and tissue damage through production of reactive oxygen/nitrogen (ROS/RNS) species and quinone metabolites of APAP. Although ROS/RNS are known to modify DNA, the effect of APAP on DNA modifications has not been studied systematically. In this study, we investigate whether large doses of APAP can modify the nuclear DNA in C6 glioma cells used as a model system, because these cells contain cytochrome P450-related enzymes responsible for APAP metabolism and subsequent toxicity (Geng and Strobel, 1995). Our results revealed that APAP produced ROS and significantly elevated the 8-oxo- deoxyguanosine (8-oxodG) levels in the nucleus of C6 glioma cells in a time and concentration dependent manner. APAP significantly reduced the 8- oxodG incision activity in the nucleus by decreasing the activity and content of a DNA repair enzyme, Ogg1. These results indicate that APAP in large doses can increase the 8-oxodG level partly through significant reduction of Ogg1 DNA repair enzyme.
Acetaminophen/*metabolism ; Analgesics, Non-Narcotic/*metabolism ; Animals ; Cell Line, Tumor ; DNA/metabolism ; DNA Damage ; DNA Glycosylases/*metabolism ; DNA Repair ; Deoxyguanosine/chemistry/*metabolism ; Glioma/*metabolism ; Glutathione/metabolism ; Humans ; Rats ; Reactive Nitrogen Species/metabolism ; Reactive Oxygen Species/metabolism

OBJECTIVETo observe the effect and mechanism of Tianyuan Ketong recipe (TKR) on the pain reaction in formalin induced pain model rats.

METHODSThe analgesic effect of TKR was evaluated using pain behavior graded scoring, the c-fos gene expression and P substance contents in superficial lamella of spinal cord dorsal horn in model rats were analyzed by means of immunohistochemical analysis and computer image analysis technique.

RESULTSTKR could markedly inhibit the pain reaction in model rats (P < 0.05), and the pain induced elevation of c-fos expression and P substance contents could also be suppressed (P < 0.05).

CONCLUSIONTKR shows definite analgesic effect on formalin induced pain model rats, the reduction of neuron's reaction in spinal cord dorsal horn to afferent noxious stimulation is possibly one of the pathways for its analgesic effect.

Analgesics, Non-Narcotic ; pharmacology ; Animals ; Drugs, Chinese Herbal ; pharmacology ; Female ; Formaldehyde ; Immunohistochemistry ; Male ; Oncogene Proteins v-fos ; biosynthesis ; genetics ; Pain ; chemically induced ; metabolism ; Posterior Horn Cells ; metabolism ; Rats ; Rats, Sprague-Dawley ; Spinal Cord ; metabolism ; Substance P ; metabolism

A series of aralkyl-ketone-4-piperidol derivatives were synthesized and tested for their analgesic activities. All of the novel 30 compounds were prepared from 4-piperidone and alpha-halo-aralkyl-ketone through five steps, including Boc protection, nucleophilic addition in presence of CeCl3/NaI catalyst, deprotection, condensation and salification. Their structures were confirmed by 1H NMR and HRMS. Preliminary in vivo pharmacological trials showed that most of the synthesized compounds revealed analgesic effects. Among the tested compounds, 8, 13 and 22 exhibited potent analgesic activities in both mice writhing and mice hot plate model. The three compounds have low affinity for mu, delta, kappa receptors, which is a chance to find a better precursor of non-opioid analgesic for further optimization.
Analgesics, Non-Narcotic ; chemical synthesis ; chemistry ; pharmacology ; Animals ; Mice ; Molecular Structure ; Pain Measurement ; Pain Threshold ; drug effects ; Piperidones ; chemical synthesis ; chemistry ; pharmacology ; Receptors, Opioid, delta ; metabolism ; Receptors, Opioid, kappa ; metabolism ; Receptors, Opioid, mu ; metabolism ; Structure-Activity Relationship

To explore novel non-opioid analgesic agents, 16 compounds were synthesized and their structures were confirmed by 1H NMR and HR-MS. YX0611-1 was treated as the leading compound. The results of mice writhing model and hot plate model showed that compounds 2, 7, 8, 9, 11 and 15 had obvious analgesic activities in vivo. The test of affinity to mu, delta, kappa receptor displayed that active compounds didn't act on opioid receptor. The results of preliminary toxicity and pharmacokinetic tests showed that compound 7 had better safety and pharmacokinetic properties than that of YX0611-1, and it deserved further development.
Analgesics, Non-Narcotic ; chemical synthesis ; chemistry ; pharmacokinetics ; pharmacology ; toxicity ; Animals ; Female ; Male ; Mice ; Pain Measurement ; Piperazines ; chemical synthesis ; chemistry ; pharmacokinetics ; pharmacology ; toxicity ; Random Allocation ; Receptors, Opioid ; metabolism ; Structure-Activity Relationship

Acetaminophen, also known as N-acetyl-p-aminophenol (APAP), is commonly used as an antipyretic and analgesic agent. APAP overdose can induce hepatic toxicity, known as acetaminophen-induced liver injury (AILI). However, therapeutic doses of APAP can also induce AILI in patients with excessive alcohol intake or who are fasting. Hence, there is a need to understand the potential pathological mechanisms underlying AILI. In this review, we summarize three main mechanisms involved in the pathogenesis of AILI: hepatocyte necrosis, sterile inflammation, and hepatocyte regeneration. The relevant factors are elucidated and discussed. For instance, N-acetyl-p-benzoquinone imine (NAPQI) protein adducts trigger mitochondrial oxidative/nitrosative stress during hepatocyte necrosis, danger-associated molecular patterns (DAMPs) are released to elicit sterile inflammation, and certain growth factors contribute to liver regeneration. Finally, we describe the current potential treatment options for AILI patients and promising novel strategies available to researchers and pharmacists. This review provides a clearer understanding of AILI-related mechanisms to guide drug screening and selection for the clinical treatment of AILI patients in the future.
Acetaminophen/toxicity* ; Analgesics, Non-Narcotic/toxicity* ; Animals ; Chemical and Drug Induced Liver Injury/pathology* ; Chemical and Drug Induced Liver Injury, Chronic/pathology* ; Humans ; Inflammation/metabolism* ; Liver/pathology* ; Mice ; Mice, Inbred C57BL ; Necrosis/pathology*

OBJECTIVECapsaicin transfersomes were prepared and its quality specifications were evaluated.

METHODCapsaicin transfersomes were prepared by high shear dispersing machine and evaluated on the entrapment efficiency, drugs release rate and in vitro skin permeation.

RESULTCapsaicin transfersomes is composed of single unilamellar vesicles, with average size of 150.6 nm. Capsaicin entrapment efficiency achieved 96.7% while concentration of lecithin used was 8%. cumulative release amount of capsaicin was in direct proportion to the ethanol concentration in the medium. The in vitro rate cumulative penetration rate of capsaicin was higher in transfersomes than in cream and suspension in rats. Adomen skin cumulative penetration rate in vitro of capsaicin transfersomes in mouse was significantly higher than that from rat and men. In the same way,cumulative penetration rate in vitro of capsaicin transfersomes through abdomen skin epidermal membrance was significantly higher than that with derma and full skin in men.

CONCLUSIONEntrapment efficiency of capsaicin transfersomes reached 96.7%, meeting the criterion of China pharmacopia( > 80%), skin penetration of capsaicin was enhanced by a capsaicin transfersomes preparation and was affected by diverse characters and levels of skin.

Administration, Cutaneous ; Analgesics, Non-Narcotic ; administration & dosage ; pharmacokinetics ; Animals ; Capsaicin ; administration & dosage ; pharmacokinetics ; Drug Carriers ; Drug Delivery Systems ; methods ; Humans ; In Vitro Techniques ; Male ; Mice ; Particle Size ; Phosphatidylcholines ; administration & dosage ; chemistry ; pharmacology ; Rats ; Skin ; drug effects ; metabolism ; Skin Absorption ; drug effects

OBJECTIVETo explore the effect of lappaconitine on patient-controlled intravenous analgesia (PCIA) and serum complement 3 and 4 (C3 and C4) levels of cancer patients undergoing rectum surgery.

METHODSTotally 60 patients, who were scheduled for rectum carcinoma surgery, were recruited to the study and assigned in 3 groups, the blank control group, the tramadol group, and the lappaconitine group, 20 in each group. Lappaconitine (8 mg) was intravenously dripped to patients in the lappaconitine group 30 min before ending the operation. PCIA started as soon as the end of the surgery and the total dose of lappaconitine was 36 mg. Patients of the tramadol group were treated with tramadol (100 mg) intravenously within 30 min before ending the operation. The dripping was completed within 30 min. PCIA was started as soon as the end of the surgery and the total dose of lappaconitine was 36 mg. Tramadol (100 mg) was intravenously dripped to patients in the tramadol group 30 min before ending the operation. PICA was started as soon as the end of the surgery and the total dose of tramadol was 900 mg. Pethidine (50 mg) and droperidol (2. 5 mg) was intramuscularly injected to patients in the blank control group for pain relief according to their complaints. Pain degrees were assessed by visual analog scale (VAS) 12 h before surgery, 12, 24, 48, and 72 h after surgery. Blood samples were withdrawn at the same time point. Contents of serum C3 and C4 were determined by immunoturbidimetry.

RESULTSVAS scores of the blank control group were significantly higher after surgery than before surgery (P <0. 01). There was no statistical difference in VAS scores between before surgery and after surgery in the tramadol group and the lappaconitine group (P >0. 05). VAS scores were significantly lower at each post-surgery time point in the tramadol group and the lappaconitine group than in the blank control group with statistical difference (P < 0.01). There was no statistical difference in VAS scores at each post-surgery time point between the tramadol group and the lappaconitine group (P >0. 05). Compared with before surgery, contents of serum C3 and C4 significantly decreased in all of the three groups at 12, 24, and 48 h after surgery (P < 0.05, P < 0.01). They recovered to the pre-surgery level till 72 h after surgery (P > 0.05). Serum C3 and C4 contents at 48 h after surgery were higher in the tramadol group than in the blank control group (P < 0.05). Serum C3 and C4 contents at 24 and 48 h after surgery were higher in the lappaconitine group than in the blank control group (P < 0.05). There was no statistical difference in serum C3 and C4 contents at each time point between the tramadol group and the lappaconitine group (P > 0.05). VAS scores were obviously negatively correlated with serum contents of C3 and C4 (r = -0.622, r = -0.649, P < 0.01).

CONCLUSIONSLappaconitine (used at the dose in this study) showed better pain relief effect after surgery. Besides, it could inhibit the surgic wound and pain, and elevate serum contents of C3 and C4.

Aconitine ; analogs & derivatives ; therapeutic use ; Analgesia, Patient-Controlled ; methods ; Analgesics, Non-Narcotic ; therapeutic use ; Complement C3 ; metabolism ; Digestive System Surgical Procedures ; Humans ; Neoplasms ; Orthopedic Procedures ; Pain Measurement ; Pain, Postoperative ; Postoperative Period ; Rectum ; surgery ; Tramadol

Rotundine (1 micromol L(-1)) was incubated with a panel of rCYP enzymes (1A2, 2C9, 2C19, 2D6 and 3A4) in vitro. The remained parent drug in incubates was quantitatively analyzed by an Agilent LC-MS. CYP2C19, 3A4 and 2D6 were identified to be the isoenzymes involved in the metabolism of rotundine. The individual contributions of CYP2C19, 3A4 and 2D6 to the rotundine metabolism were assessed using the method of total normalized rate to be 31.46%, 60.37% and 8.17%, respectively. The metabolites of rotundine in incubates were screened with ESI-MS at selected ion mode, and were further identified using MS2 spectra and precise molecular mass obtained from an Agilent LC/Q-TOF-MSMS, as well as MS(n) spectra of LC-iTrap-MS(n). The predominant metabolic pathway of rotundine in rCYP incubates was O-demethylation. A total 5 metabolites were identified including 4 isomerides of mono demethylated rotundine and one di-demethylated metabolite. The results also showed that CYP2C19, 2D6 and 3A4 mediated O-demethylation of methoxyl groups at different positions of rotundine. Furthermore, the ESI-MS cleavage patterns of rotundine and its metabolites were explored by using LC/Q-TOF-MSMS and LC/iTrap-MS(n) techniques.
Analgesics, Non-Narcotic ; metabolism ; Aryl Hydrocarbon Hydroxylases ; metabolism ; Berberine Alkaloids ; metabolism ; Chromatography, Liquid ; Cytochrome P-450 CYP1A2 ; metabolism ; Cytochrome P-450 CYP2C19 ; Cytochrome P-450 CYP2C9 ; Cytochrome P-450 CYP2D6 ; metabolism ; Cytochrome P-450 CYP3A ; metabolism ; Cytochrome P-450 Enzyme System ; metabolism ; Dopamine Antagonists ; metabolism ; Humans ; Isoenzymes ; metabolism ; Methylation ; Recombinant Proteins ; metabolism ; Spectrometry, Mass, Electrospray Ionization

The purpose of this study is to evaluate the interaction effects of In-Chen-How (Artemisia capillaries Thunb.) on the pharmacokinetics of acetaminophen and on liver microsomal cytochrome P450 enzyme activity in rats. The rats were divided into control group (n = 8) without In-Chen-How and the pretreated group (n = 8) administered with In-Chen-How (approximately 1.0 mL x kg(-1), according to weight) for 5 consecutive days. Rats in the control group received water simultaneously. Each rat was then given acetaminophen. The pharmacokinetic parameters of acetaminophen of the two groups were significantly different. In the In-Chen-How pretreated group, the maximum concentration of acetaminophen and the area under the plasma concentration-time curve were reduced about 58.4%, 56.7% and 55.4%. To further explain the results, liver microsomal suspensions were obtained from rats that were randomly divided into control and In-Chen-How pretreated group. The levels of CYP1A2 and CYP2E1 in hepatic microsomal protein from pretreated group were increased as compared to that from the control group. It indicated that In-Chen-How can stimulate the activity of CYP isozymes. The changes in the pharmacokinetics of acetaminophen resulting from the administration of In-Chen-How are related to an increase in metabolic activity of CYP1A2 and CYP2E1.
Acetaminophen ; administration & dosage ; blood ; pharmacokinetics ; Administration, Oral ; Analgesics, Non-Narcotic ; administration & dosage ; blood ; pharmacokinetics ; Animals ; Area Under Curve ; Artemisia ; chemistry ; Aryl Hydrocarbon Hydroxylases ; metabolism ; Cytochrome P-450 CYP1A2 ; metabolism ; Cytochrome P-450 CYP2E1 ; metabolism ; Drug Interactions ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; Immunoblotting ; Male ; Metabolic Clearance Rate ; drug effects ; Microsomes, Liver ; drug effects ; enzymology ; Plants, Medicinal ; chemistry ; Random Allocation ; Rats ; Rats, Wistar