Fentanyl Promoted the Growth of Placenta Trophoblast Cells through Regulating the METTL14 Mediated CCL5 Levels.

Gestational diabetes mellitus (GDM) is an important cause of the increase in incidence rate and mortality of pregnant women and perinatal infants. This study aimed to analyze the role of fentanyl, a µ-opioid agonist, in the GDM progression. The high glucose (HG) treatment HTR8/SVneo cells was used as a GDM model in vitro. The cell viability was assessed with cell counting kit-8 assay. The apoptosis rate was analyzed with flow cytometry and the transwell assay was conducted to test the cell migration and invasion. RT-quantitative PCR (qPCR) assay was performed to determine the relative expressions of related genes. The N6-Methyladenosine (m6A) levels were analyzed with MeRIP analysis. The tumor necrosis factor-α (TNF-α), interleukin 1ß (IL-1ß), and IL-10 levels of the cells were analyzed with commercial kits. The results showed that fentanyl increased the cell viability, migration and invasion, and IL-10 levels, and declined the apoptosis rate, TNF-α and IL-1ß levels of the HG stimulated HTR8/SVneo cells. The chemokine ligand 5 (CCL5) was over expressed in GDM tissues and HG stimulated HTR8/SVneo cells, which was depleted after fentanyl treatment. Over expressed CCL5 neutralized the fentanyl roles in the HG stimulated HTR8/SVneo cells. The methyltransferase-like protein 14 (METTL14) levels was decreased in HG stimulated HTR8/SVneo cells, which was up-regulated after fentanyl treatment. Additionally, METTL14 silenced prominently decreased the m6A and mRNA levels, along with the mRNA stability of CCL5. In conclusion, fentanyl promoted the growth and inhibited the apoptosis of the HG stimulated HTR8/SVneo cells through regulating the METTL14 mediated CCL5 levels.

A single dose of ketamine relieves fentanyl-induced-hyperalgesia by reducing inflammation initiated by the TLR4/NF-κB pathway in rat spinal cord neurons.

A large amount of clinical evidence has revealed that ketamine can relieve fentanyl-induced hyperalgesia. However, the underlying mechanism is still unclear. In the current study, a single dose of ketamine (5 mg/kg or 10 mg/kg), TAK-242 (3 mg/kg), or saline was intraperitoneally injected into rats 15 min before four subcutaneous injections of fentanyl. Results revealed that pre-administration of ketamine alleviated fentanyl-induced hyperalgesia according to hind paw-pressure and paw-withdrawal tests. High-dose ketamine can reverse the expression of toll-like receptor-dimer (d-TLR4), phospho- nuclear factor kappa-B (p-NF-κB, p-p65), cyclooxygenase-2 (COX-2), interleukin-1ß (IL-1ß), and tumor necrosis factor-α (TNF-α) 1 d after fentanyl injection in the spinal cord. Moreover, fentany-linduced-hyperalgesia and changes in the expression of the aforementioned proteins can be attenuated by TAK-242, an inhibitor of TLR4, as well as ketamine. Importantly, TLR4, p-p65, COX-2, and IL-1ß were expressed in neurons but not in glial cells in the spinal cord 1 d after fentanyl injection. In conclusion, results suggested that a single dose of ketamine can relieve fentanyl-induced-hyperalgesia via the TLR4/NF-κB pathway in spinal cord neurons.

Fentanyl alleviates intestinal mucosal barrier damage in rats with severe acute pancreatitis by inhibiting the MMP-9/FasL/Fas pathway.

BACKGROUND: Fentanyl is an analgesic used against pancreatitis-related pain, while whether it ameliorates severe acute pancreatitis (SAP) has yet to be checked. This study aims to determine fentanyl-delivered effect on SAP and the mechanism underlying this effect. METHODS: Rat SAP models were established, following fentanyl treatment. The serum activity of amylase (AMY), lipase (LIP), and diamine oxidase (DAO) was detected by enzyme-linked immunosorbent assay (ELISA). Histological examination was performed in the pancreatic and intestinal tissues with hematoxylin-eosin staining. After transfection with matrix metalloproteinase (MMP) 9 overexpression plasmids, Caco-2 monolayers were treated with fentanyl and subsequently exposed to lipopolysaccharide (LPS). The transepithelial electrical resistance (TEER) value was determined in rat intestinal mucosa through an Ussing chamber assisted by Analyze & Acquire, and in Caco-2 cell monolayers through a voltohmmeter. Intestinal mucosa and paracellular permeabilities were determined by fluorescein isothiocyanate (FITC)-labeled dextran assay. The expressions of ZO-1, Occludin, MMP9, Fas and Fas ligand (FasL) in rat intestinal mucosa and/or Caco-2 monolayers were analyzed by qRT-PCR or/and western blot. RESULTS: Fentanyl alleviated SAP-related histological alterations in the pancreas and intestines, reduced the elevated levels of SAP-related AMY, LIP, and DAO, but promoted the levels of ZO-1 and Occludin. In SAP rats and Caco-2 monolayers, SAP-related or LPS-induced TEER value decreases, permeability increases, and increases in the expressions of MMP9, Fas, and FasL were reversed partly by fentanyl. Notably, MMP9 overexpression could reverse the above fentanyl-delivered in vitro effects. CONCLUSIONS: Fentanyl alleviates intestinal mucosal barrier damage in rats with SAP by inhibiting the MMP9/FasL/Fas pathway.

Untargeted Metabolomics in Forensic Toxicology: A New Approach for the Detection of Fentanyl Intake in Urine Samples.

The misuse of fentanyl, and novel synthetic opioids (NSO) in general, has become a public health emergency, especially in the United States. The detection of NSO is often challenged by the limited diagnostic time frame allowed by urine sampling and the wide range of chemically modified analogues, continuously introduced to the recreational drug market. In this study, an untargeted metabolomics approach was developed to obtain a comprehensive "fingerprint" of any anomalous and specific metabolic pattern potentially related to fentanyl exposure. In recent years, in vitro models of drug metabolism have emerged as important tools to overcome the limited access to positive urine samples and uncertainties related to the substances actually taken, the possible combined drug intake, and the ingested dose. In this study, an in vivo experiment was designed by incubating HepG2 cell lines with either fentanyl or common drugs of abuse, creating a cohort of 96 samples. These samples, together with 81 urine samples including negative controls and positive samples obtained from recent users of either fentanyl or "traditional" drugs, were subjected to untargeted analysis using both UHPLC reverse phase and HILIC chromatography combined with QTOF mass spectrometry. Data independent acquisition was performed by SWATH in order to obtain a comprehensive profile of the urinary metabolome. After extensive processing, the resulting datasets were initially subjected to unsupervised exploration by principal component analysis (PCA), yielding clear separation of the fentanyl positive samples with respect to both controls and samples positive to other drugs. The urine datasets were then systematically investigated by supervised classification models based on soft independent modeling by class analogy (SIMCA) algorithms, with the end goal of identifying fentanyl users. A final single-class SIMCA model based on an RP dataset and five PCs yielded 96% sensitivity and 74% specificity. The distinguishable metabolic patterns produced by fentanyl in comparison to other opioids opens up new perspectives in the interpretation of the biological activity of fentanyl.

Influences of UGT2B7 rs7439366 and rs12233719 Polymorphisms on Fentanyl Sensitivity in Chinese Gynecologic Patients.

BACKGROUND This study discussed potential influences of UDP glucuronosyltransferase family 2 member B7 (UGT2B7) rs7439366 and rs12233719 polymorphisms on fentanyl sensitivity among Chinese gynecologic patients. MATERIAL AND METHODS UGT2B7 polymorphisms were genotyped by polymerase chain reaction (PCR) and direct sequencing. Before surgery, baseline latency to pain perception (PPLpre) and pain perception latency of the dominant hand (PPLpost) at 3 minutes after injecting fentanyl were measured by cold pressor-induced pain test. Perioperative fentanyl adoption referred to the total of fentanyl administration during and after operation. Intensity of spontaneous pain was appraised adopting 100-mm visual analog scale (VAS). Factorial analysis was performed by Mann-Whitney U test and Kruskal-Wallis H test. RESULTS Significant differences of PPLpost (CC/CT/TT, P=0.038) and preoperative analgesic effect (CC/CT/TT, P=0.028) were discovered between the rs7439366 genotypes. PPLpost was significantly different between the CT and TT groups (P=0.009) and the CC+CT and TT groups (P=0.026). Preoperative analgesic effect was significantly different between the CT and TT groups (P=0.007) and the CC+CT and TT groups (P=0.009). All of the clinical features studied had no close association with rs12233719 SNP. CONCLUSIONS Gynecologic patients with rs7439366 TT genotype had significantly lower fentanyl sensitivity than the other 2 genotype carriers.

Modulation of the Gloeobacter violaceus Ion Channel by Fentanyl: A Molecular Dynamics Study.

Fentanyl is an opioid analgesic, which is routinely used in general surgery to suppress the sensation of pain and as the analgesic component in the induction and maintenance of anesthesia. Fentanyl is also used as the main component to induce anesthesia and as a potentiator to the general anesthetic propofol. The mechanism by which fentanyl induces its anesthetic action is still unclear, and we have therefore employed fully atomistic molecular dynamics simulations to probe this process by simulating the interactions of fentanyl with the Gloeobacter violaceus ligand-gated ion channel (GLIC). In this paper, we identify multiple extracellular fentanyl binding sites, which are different from the transmembrane general anesthetic binding sites observed for propofol and other general anesthetics. Our simulations identify a novel fentanyl binding site within the GLIC that results in conformational changes that inhibit conduction through the channel.

Minor contribution of cytochrome P450 3A activity on fentanyl exposure in palliative care cancer patients.

Transdermal fentanyl is widely used to control pain in cancer patients. The high pharmacokinetic variability of fentanyl is assumed to be due to cytochrome P450 3A-mediated (CYP3A) N-dealkylation to norfentanyl in humans. However, recently published clinical studies question the importance of the described metabolic pathway. In this small study in palliative cancer patients under real-life clinical conditions, the influence of CYP3A on fentanyl variability was investigated. In addition to the determination of midazolam plasma concentration to reveal CYP3A activity, plasma concentrations of fentanyl and its metabolite, norfentanyl, were measured in identical blood samples of 20 patients who participated in an ongoing trial and had been on transdermal fentanyl. Fentanyl, norfentanyl, midazolam, and 1'-OH-midazolam were quantified by liquid chromatography/tandem mass spectrometry. Plasma concentrations of fentanyl and norfentanyl exhibited a large variability. Mean estimated total clearance of fentanyl and mean metabolic clearance of midazolam (as a marker of CYP3A activity) were 75.5 and 36.3 L/h. Both clearances showed a weak correlation and hence a minimal influence of CYP3A on fentanyl elimination.

[Study of the Metabolism of New Drugs of Abuse].

Human hepatocytes possess a wider range of phase I and II drug-metabolizing enzyme activities than other liver tissue-derived products, such as human liver microsomes. Thus, hepatocytes may be useful for predicting the in vivo metabolic fate of new drugs of abuse in humans. Recently, new types of human hepatocytes have been made commercially available for use in drug metabolism studies, such as a liver tumor-derived cell line (HepaRG), and a human induced pluripotent stem cell-derived hepatocyte (h-iPS-HEP). In our laboratory, HepaRG has been used to elucidate the metabolic pathways of XLR-11, a synthetic cannabinoid, and its thermal degradant. In addition, the potential of h-iPS-HEP to metabolize drugs was assessed using fentanyl as a model drug, and indeed, h-iPS-HEP exhibited a pattern for fentanyl metabolite formation similar to that observed in vivo. In addition, the phase I and II drug-metabolizing enzyme activities of HepaRG, h-iPS-HEP, liver-humanized mouse-derived hepatocytes (PXB-cellsTM), and human primary hepatocytes were evaluated and compared. HepaRG showed high phase I and II drug metabolism activities; however, the CYP2D6 activity in these cells was quite low, and therefore h-iPS-HEP lacked O-methylation and conjugation activities. PXB-cells provided optimal results, i.e., these cells are extremely easy to use, and they possess higher phase I and II drug-metabolizing enzyme activities than the other cells tested. Although PXB-cells are contaminated with mouse-derived cells up to a concentration of several percent, this cell system appears to be promising for the prediction of in vivo human metabolism of new drugs of abuse.

Testing hair for fentanyl exposure: a method to inform harm reduction behavior among individuals who use heroin.

BACKGROUND: Deaths from fentanyl exposure continue to increase in the US. Fentanyl test strips are now available to test urine for presence of fentanyl, but additional testing methods are needed to determine past exposure and to determine exposure to specific analogs. OBJECTIVES: To investigate exposure to such analogs through hair testing. METHODS: Forty individuals in inpatient detoxification (7.5% female) reporting past-month heroin use were surveyed and provided a hair sample to be tested at a later date. While results could not be provided to patients, they were asked how they would respond if informed that their hair tested positive for fentanyl. UHPLC-MS/MS was used to test for past exposure to fentanyl, six other novel synthetic opioids, and fentanyl biomarkers/metabolites. RESULTS: 27.5% reported known fentanyl use in the past year and 67.5% reported suspected exposure. 97.5% (39 of 40) tested positive for fentanyl, 90.0% tested positive for 4-ANPP (a biomarker) and norfentanyl (a metabolite); 82.5% tested positive for acetyl-fentanyl, 47.5% tested positive for furanyl-fentanyl, and 7.5% tested positive for U-47700. Most participants (82.5%) reported they would warn others about fentanyl if they learned their hair tested positive; 75.0% reported they would try to stop using heroin, and 65.0% reported they would ensure that someone nearby has naloxone to reverse a potential overdose. CONCLUSIONS: Hair testing is useful in detecting past exposure to fentanyl, its analogs, and other novel synthetic opioids. Further research is needed to determine whether individuals who use heroin learning about exposure affects drug-taking and treatment-seeking behavior.

In vitro Characterization of NPS Metabolites Produced by Human Liver Microsomes and the HepaRG Cell Line Using Liquid Chromatographyhigh Resolution Mass Spectrometry (LC-HRMS) Analysis: Application to Furanyl Fentanyl.

BACKGROUND: Identification of metabolites is of importance in the challenge of new psychoactive substances (NPS) as it could improve the detection window in biological matrices in clinical and forensic cases of intoxication. Considering the numerous and diverse NPS reported each year, producers increasingly appear today to be targeting non-controlled synthetic opioids, involving fentanyl derivatives such as furanyl fentanyl (Fu-F). OBJECTIVE: This work aims to investigate and compare metabolites of Fu-F using two in vitro experimental approaches. METHODS: CYP- and UGT-dependent metabolites of Fu-F were investigated by means of analyses of both human liver microsome (HLM) and hepatic (HepaRG) cell line incubates using liquid chromatography with high-resolution mass detection and, subsequently, compared and confronted to recently published data. RESULTS: Seventeen Fu-F metabolites were produced and several metabolic pathways can be postulated. HLMs and HepaRG cultures appear to be complementary: HepaRG cells produced 9 additional metabolites, but which appear to be minor in vivo metabolites. Specific* and/or abundant Fu-F metabolites are dihydrodiol-Fu-F*, norFu-F* and despropionylfentanyl. However, norFu-F seems to be inconstantly observed in in vivo cases. Furthermore, a sulfate metabolite presents at significant rate in urine obtained from FU-F users was not identified here, as in another in vitro study. CONCLUSION: HLMs represent an acceptable first choice tool for a single NPS metabolism study in forensic laboratories. Dihydrodiol-Fu-F and despropionylfentanyl could be proposed as reliable metabolites to be recorded in HRMS libraries in order to improve detection of Fu-F users. Nevertheless, additional verifications of in vivo data remain necessary to confirm relevant blood and urinary metabolites of Fu-F.

Time-dependent postmortem redistribution of butyrfentanyl and its metabolites in blood and alternative matrices in a case of butyrfentanyl intoxication.

A fatal case of butyrfentanyl poisoning was investigated at the Zurich Institute of Forensic Medicine. At admission at the institute approx. 9h after death (first time point, t1), femoral and heart blood (right ventricle) was collected, as well as samples from the lung, liver, kidney, spleen, muscle and adipose tissue using computed tomography (CT)-guided biopsy sampling. At autopsy (t2), samples from the same body regions were collected manually. Additionally, urine, heart blood (left ventricle), gastric content, brain samples and hair were collected. Butyrfentanyl concentrations and relative concentrations of the metabolites carboxy-, hydroxy-, nor-, and desbutyrfentanyl were determined by LC-MS/MS and LC-QTOF. At t1, butyrfentanyl concentrations were 66ng/mL in femoral blood, 39ng/mL in heart blood, 110ng/g in muscle, 57ng/g in liver, 160ng/g in kidney, 3100ng/g in lung, 590ng/g in spleen and 550ng/g in adipose tissue. At t2, butyrfentanyl concentration in urine was 1100ng/mL, in gastric content 2000ng/mL, in hair 11,000pg/mg and brain concentrations ranged between 200-340ng/g. Carboxy- and hydroxybutyrfentanyl were identified as most abundant metabolites. Comparison of t1 and t2 showed a concentration increase of butyrfentanyl in femoral blood of 120%, in heart blood of 55% and a decrease in lung of 30% within 19h. No clear concentration changes could be observed in the other matrices. Postmortem concentration changes were also observed for the metabolites. In conclusion, butyrfentanyl seems to be prone to postmortem redistribution processes and concentrations in forensic death cases should be interpreted with caution.

CYP3A4 * 1G Genetic Polymorphism Influences Metabolism of Fentanyl in Human Liver Microsomes in Chinese Patients.

PURPOSE: This study aimed to investigate whether CYP3A4*1G genetic polymorphism influences the metabolism of fentanyl in human liver microsomes in Chinese patients. METHODS: The human liver microsomes were obtained from 88 hepatobiliary surgery patients who accepted liver resection surgery in this study. A normal liver sample (confirmed by the Department of Pathology) was taken from the outer edge of the resected tissue. The metabolism of fentanyl in human liver microsomes was studied. The concentration of fentanyl was measured by high performance liquid chromatography. The CYP3A4*1G variant allele was genotyped using the PCR restriction fragment length polymorphism method. RESULTS: The frequency of the CYP3A4*1G variant allele was 0.188 in the 88 Chinese patients who had received hepatobiliary surgery. The metabolic rate of fentanyl in patients homozygous for the *1G/*1G variant (0.85 ± 0.37) was significantly lower than that in patients bearing the wild-type allele *1/*1 (1.89 ± 0.58) or in patients heterozygous for the *1/*1G variant (1.82 ± 0.65; p < 0.05). There were no gender-related differences in the metabolic rate of fentanyl (p > 0.05) nor was there any correlation between age and metabolic rate of fentanyl (p > 0.05). Results from different hepatobiliary diseases showed no significant difference in the metabolic rate of fentanyl (p > 0.05). The difference of CYP3A4 mRNA among different CYP3A4*1G variant alleles was significant (p < 0.05). There was positive correlation between CYP3A4 mRNA and metabolic rate of fentanyl (p < 0.01). CONCLUSIONS: CYP3A4*1G genetic polymorphism decreases the metabolism of fentanyl. There is a positive correlation between CYP3A4 mRNA level and metabolism of fentanyl.

Permeability test for transdermal and local therapeutic patches using Skin PAMPA method.

Using the skin as absorption site presents unique advantages that have facilitated the progression of transdermal drug delivery in the past decades. Efforts in drug research have been devoted to find a quick and reproducible model for predicting the skin permeation of molecules. The Parallel Artificial Membrane Permeability Assay (PAMPA) has been extended for prediction of transdermal permeation by developing a model with completely artificial membrane, which can mimic the permeation through the stratum corneum. The present study aims to extend the Skin PAMPA method for testing transdermal and local therapeutic patches. The original method was modified and seven commercially available transdermal and local therapeutic patches with four different active pharmaceutical ingredients (nicotine, fentanyl, rivastigmine and ketoprofen) were studied. Data were compared to the declared delivery rates that are indicated by the manufacturers. Ex vivo permeation study was also performed in order to compare the permeated amount of the released drugs obtained by the two methods. The flux across the artificial membrane as well as the human skin (ex vivo) has been calculated and compared to the in vivo flux deduced from the labelled delivery rate and the active area of the patches. The results suggest that Skin PAMPA system can serve as a useful tool for evaluation and classification of the transdermal patches.

[Interindividual variation of pharmacokinetic disposition of and clinical responses to opioid analgesics in cancer pain patients].

Use of prescription opioids for cancer pain according to the World Health Organization analgesic ladder has been accepted in Japan. Although oxycodone and fentanyl are commonly used as first-line analgesics, a few clinical reports have been published on interindividual variations in their pharmacokinetics and clinical responses in cancer patients. (1) Some factors relating to CYP2D6, CYP3A, ATP-binding cassette sub-family B member 1 (ABCB1), and opioid receptor mu 1 (OPRM1) involve oxycodone pharmacokinetics and sensitivity in humans. The relations between their genetic variations and clinical responses to oxycodone are being revealed in limited groups. In our study, the impact of genetic variants and pharmacokinetics on clinical responses to oxycodone were evaluated in Japanese populations. (2) Opioid switching improves the opioid tolerance related to the balance between analgesia and adverse effects. Some patients have difficulty in obtaining better opioid tolerance in recommended conversion ratios. The activities of CYP3A, ABCB1, and OPRM1 contribute to the interindividual variations in clinical responses to fentanyl in cancer patients. However, the variations in opioid switching remain to be clarified in clinical settings. In our study, genetic factors related to interindividual variations in clinical responses in opioid switching to fentanyl were revealed in Japanese populations. In this symposium review, the possibility of approaches to personalized palliative care using opioids based on genetic variants of CYP2D6, CYP3A5, ABCB1, and OPRM1 is discussed.

Protein binding of fentanyl and its metabolite nor-fentanyl in human plasma, albumin and α-1 acid glycoprotein.

1.Fentanyl is a highly lipophilic opioid commonly used to treat cancer pain. Plasma protein binding (PPB) of fentanyl in human plasma is reported as 80-85%, however it is unclear whether fentanyl binds primarily to albumin (ALB) or α-1 acid glycoprotein (AAG) and no studies have been conducted on the metabolite, nor-fentanyl. Fentanyl is also known to bind to plasticware and ultrafiltration (UF) devices which impacts adversely on binding experiments. 2.PPB of fentanyl and nor-fentanyl to ALB and AAG in isotonic phosphate buffer solution and seeded human plasma was quantified. PPB was also performed in plasma samples obtained from cancer patients receiving transdermal fentanyl. The adsorption of fentanyl and nor-fentanyl to UF devices and plasticware commonly used in PPB studies was also assessed. 3.Fentanyl was shown to bind primarily to ALB as opposed to AAG, with nor-fentanyl exhibiting negligible binding to plasma proteins. Total PPB of fentanyl was 86-89% in seeded human plasma. PPB in 56 cancer patient samples was 95.1 ± 3.52% for fentanyl and 32.4 ± 21.9% for nor-fentanyl. 4.UF was shown to be a reliable and convenient method for PPB studies, thereby removing the need for complex testing for adsorption of the drug to plasticware during UF.

Association between genetic polymorphisms of the ß1-adrenergic receptor and sensitivity to pain and fentanyl in patients undergoing painful cosmetic surgery.

Individual differences in the sensitivity to fentanyl, a widely used opioid analgesic, can hamper effective pain treatment. The adrenergic system is reportedly involved in the mechanisms of pain and analgesia. Here, we focused on one of the adrenergic receptor genes, ADRB1, and analyzed the influence of single-nucleotide polymorphisms (SNPs) in the ADRB1 gene on individual differences in pain and analgesic sensitivity. We examined associations between pain and fentanyl sensitivity and the two SNPs, A145G and G1165C, in the human ADRB1 gene in 216 Japanese patients who underwent painful orofacial cosmetic surgery, including bone dissection. The patients who carried the A-allele of the A145G SNP were more sensitive to cold pressor- induced pain than those who did not carry this allele, especially in male patients. The analgesic effect was significantly less in females who carried the G-allele of the G1165C SNP than the females who did not carry the G-allele. The haplotype analysis revealed a significant decrease in 24-h postoperative fentanyl use in female 145A/1165C haplotype carriers. These results suggest that SNPs in the ADRB1 gene are associated with individual differences in pain and analgesic sensitivity, and analyzing these SNPs may promote personalized pain treatment in the future.

Influence of CYP3A5*3 polymorphism and interaction between CYP3A5*3 and CYP3A4*1G polymorphisms on post-operative fentanyl analgesia in Chinese patients undergoing gynaecological surgery.

BACKGROUND AND OBJECTIVE: Fentanyl is metabolised by cytochrome P450 (CYP) 3A4 and CYP3A5. Our previous work demonstrated that the CYP3A4*1G polymorphism significantly affects the post-operative fentanyl analgesic effect in Chinese women undergoing gynaecological surgery. However, whether CYP3A5*3, a frequent single nucleotide polymorphism of CYP3A5 in Chinese people, affects the post-operative analgesic effect of fentanyl is unclear. In this study, we assessed the influence of the CYP3A5*3 polymorphism and the interaction of the CYP3A5*3 and CYP3A4*1G polymorphisms on post-operative fentanyl analgesia in Chinese women undergoing gynaecological surgery. METHODS: We enrolled 203 women scheduled for abdominal total hysterectomy or myomectomy under general anaesthesia. Intravenous fentanyl patient-controlled analgesia was provided post-operatively for adequate analgesia. Pain scores and fentanyl consumption were recorded 24 h post-operatively. Midazolam was used as a probe drug, and CYP3A activity was measured by plasma ratio of 1'-hydroxymidazolam to midazolam 1 h after intravenous administration of 0.1 mg kg-1 midazolam. Blood samples were genotyped for the CYP3A5*3 polymorphism. RESULTS: The frequency of the CYP3A5*3 allele was 72.4% in 203 patients. CYP3A activity did not differ among CYP3A5*3 genotypes. Fentanyl consumption 24 h post-operatively was lower with CYP3A5*1/*3 and CYP3A5*3/*3 polymorphisms than with CYP3A5*1/*1, but the differences were not statistically significant. However, combined with CYP3A4*1G polymorphism, post-operative fentanyl consumption at 24 h was significantly lower for the CYP3A5*1/*3 or CYP3A5*3/*3 group than the CYP3A5*1/*1 group. CONCLUSION: CYP3A5*3 is not the main genetic factor contributing to interindividual variation in the post-operative analgesic effect of fentanyl in Chinese women undergoing gynaecological surgery; an interaction between CYP3A5*3 and CYP3A4*1G polymorphisms can significantly influence the post-operative effect.

Insulin resistance influences central opioid activity in polycystic ovary syndrome.

This pilot study describes a relationship between insulin resistance and µ-opioid neurotransmission in limbic appetite and mood-regulating regions in women with polycystic ovary syndrome (PCOS), suggesting that insulin-opioid interactions may contribute to behavioral and reproductive pathologies of PCOS. We found that [1] patients with PCOS who are insulin-resistant (n = 7) had greater limbic µ-opioid receptor availability (nondisplaceable binding potential) than controls (n = 5); [2] receptor availability was correlated with severity of insulin resistance; and [3] receptor availability normalized after insulin-regulating treatment.

Impact of CYP3A4*1G polymorphism on metabolism of fentanyl in Chinese patients undergoing lower abdominal surgery.

PURPOSE: This study aimed to investigate the impact of CYP3A4*1G genetic polymorphism on metabolism of fentanyl in Chinese patients undergoing lower abdominal surgery. METHODS: 176 patients receiving elective lower abdominal surgery under general anesthesia were recruited into this study. Genotyping of CYP3A4*1G was carried out by direct sequencing. The plasma fentanyl concentration was detected 30 min after anesthesia induction by high performance liquid chromatography-ultraviolet ray (HPLC-UV). The visual analog scale (VAS) was used for pain evaluation at rest during patient-controlled analgesia (PCA) treatment 0 h, 12 h and 24 h after operation. PCA fentanyl consumption and adverse effects were recorded during the first 24 h after surgery. RESULTS: The frequency of CYP3A4*1G variant allele was 0.227 (80/352, 95% CI 0.165, 0.289) in these patients. After grouping according to the genotype of CYP3A4*1G, plasma fentanyl concentration in the *1/*1 variant (wild-type) group (12.8±6.5 ng/ml) was significantly lower than that in the *1/*1G group (16.8±9.0 ng/ml, P<0.01) and the *1G/*1G group (28.1±9.5 ng/ml, P<0.01). Patients in the *1G/*1G group (247.1±73.2 µg) consumed significantly less fentanyl than that in either the wild-type group (395.0±138.5 µg) or the *1/*1G group (359.8±120.2 µg) (P<0.01). There was a significant correlation between plasma fentanyl concentration and PCA fentanyl consumption (r=-0.552, P<0.001). CONCLUSIONS: CYP3A4*1G polymorphism is related to the pharmacokinetics of fentanyl, and patients with CYP3A4*1G variant A allele have a lower metabolic rate of fentanyl. The specific CYP3A4*1G polymorphism may predict the individual requirement of fentanyl.

Preparation and in vitro evaluation of a new fentanyl patch based on functional and non-functional pressure sensitive adhesives.

In this study, some single-layer and double-layer transdermal drug delivery systems (TDDSs) with different functional and non-functional acrylic pressure-sensitive adhesives (PSAs) were prepared. For this purpose, fentanyl as a drug was used. The effects of PSAs type, single-layer and double-layer TDDSs on skin permeation and in vitro drug release from devices were evaluated using a hydrodynamically well-characterized Chien permeation system fitted with excised rat abdominal skin. The adhesion properties of devices such as peel strength and tack values were obtained as well. It was found that TDDS with -COOH functional PSA showed the lowest steady-state flux. Double-layer TDDS displayed a constant flux up to 72 h. In double- and single-layer devices after 1 and 3 h, respectively, drug release followed Higuchi's kinetic model. Formulations with the highest percentage of -COOH functional PSA have displayed the lowest flux. The double-layer TDDSs with non-functional PSA demonstrated the suitable skin permeation rate close to Duragesic(R) TDDS and suitable adhesion properties.