Development of a column-switching LC-MS/MS method of tramadol and its metabolites in hair and application to a pharmacogenetic study

Hair is a valuable specimen for monitoring long-term drug use. Tramadol is an effective opioid analgesic but is associated with risks such as drug dependence and unexpected toxicity arising from genetic differences in metabolism. However, few studies have been performed on the distribution of tramadol and its metabolites in hair. In the present study, a column-switching LC-MS/MS method was developed and fully validated for the simultaneous determination of tramadol and its phase I and II metabolites in hair. Furthermore, the distribution of tramadol and its metabolites in hair was investigated in a pharmacogenetic study. Tramadol and its metabolites were extracted from hair using methanol and injected onto LC-MS/MS. The validation results of selectivity, matrix effect, linearity, precision and accuracy were satisfactory. The (mean) concentrations of O-desmethyltramadol (ODMT) and N,O-didesmethyltramadol (NODMT) in the CYP2D6*10/*10 and CYP2D6*5/*5 groups were lower than those in the CYP2D6*wt/*wt group, while the (mean) concentrations of N-desmethyltramadol (NDMT) were higher. Moreover, the ratios of ODMT/tramadol, NDMT/tramadol and NODMT/NDMT were well correlated with the CYP2D6 genotypes. The developed method was successfully applied to the clinical study, which demonstrated that the concentrations of a drug and its metabolites in hair were dependent on the polymorphism of its metabolizing enzyme.     

Phosphatidylcholine attenuated docetaxel-induced peripheral neurotoxicity in rats

Docetaxel is a taxane chemotherapeutic agent used in the treatment of breast cancer, prostate cancer and gastric cancer, but several side effects such as peripheral neurotoxicity could occur. The present study was designed to investigate the therapeutic potential of phosphatidylcholine (PC) on docetaxel-induced peripheral neurotoxicity. Rats were randomly divided into three groups and treated for 4 weeks. Behavioral tests were conducted to measure the effects of PC on docetaxel-induced decreases in mechanical & thermal nociceptive threshold. Biochemical tests were conducted to measure the level of oxidative stress on sciatic nerve. Histopathological and immunohistochemical experiments were also conducted to assess neuronal damage and glial activation. PC treatment significantly attenuated docetaxel-induced changes in mechanical & thermal nociceptive response latencies. PC decreased oxidative stress in sciatic nerve by increasing antioxidant levels (glutathione, glutathione peroxidase and superoxide dismutase activity). In immunohistochemical evaluation, PC treatment ameliorated docetaxel-induced neuronal damage and microglial activation in the sciatic nerve and spinal cord. Thus, PC showed protective effects against docetaxel-induced peripheral neurotoxicity. These effects may be attributed to its antioxidant properties and modulation of microglia.     

Quantification of in vivo gastric fluid volume in Bama miniature pigs in fasted state

Although the study of bioequivalence waivers in humans is already well‐established, their application and translation into animals, which are complicated by differences in physiology, have only recently become subjects of interest. The main purpose of this paper is to quantify the liquid volume affecting drug dissolution in pig stomachs. We used magnetic resonance imaging (MRI) to scan 18 Bama miniature pigs weighing 15, 30 or 50 kg. Amira 6.0.1 software was used for 3D image processing. We found that the gastric fluid volume had a linear relationship with the weight of pig (R² = 0.9935) over this weight range. The pig weight, therefore, could be used as a surrogate for the fasted gastric fluid volume. After combining data of gastric fluid secretion and drinking water volumes, our results could be used as a reference for the evaluation of oral drug absorption in pigs.     

Design,synthesis and evaluation of alkylphosphocholine-gefitinib conjugates as multitarget anticancer agents

The evolving resistance to the currently used chemotherapeutic agents requires continuous efforts to develop new anticancer agents overcoming resistance and with lower side effects. Polypharmacology via designing a single molecule intercepting multiple signaling pathways is more effective than targeting a single one. Several alkylphosphocholines show anticancer activity via inhibition of Akt phosphorylation. On the other hand, several molecules having quinazoline scaffold elicit anticancer activity through inhibition of epidermal growth factor receptor (EGFR) tyrosine kinases. We report our efforts to develop alkylphosphocholines-gefitinib conjugates as multitarget anticancer agents. The antiproliferative activities of the newly synthesized compounds were evaluated against cell lines representing lung, breast, liver and skin cancers. In addition, the capability of the newly synthesized compounds to inhibit Akt phosphorylation and EGFR tyrosine kinases were determined. The results emphasized the influence of the linkers’ length on the elicited bioactivity. The long chain linkers possessing conjugates were more active regarding both of the elicited antiproliferative effect and inhibition of Akt phosphorylation, while maintained the ability to inhibit EGFR tyrosine kinases. Their cytotoxic activities were superior or comparable to erlotinib and miltefosine.     

Aspirin-inspired acetyl-donating HDACs inhibitors

Aspirin is one of the oldest drugs for the treatment of inflammation, fever, and pain. It is reported to covalently modify COX-2 enzyme by acetylating a serine amino acid residue. By virtue of aspirin’s acetylating potential, we for the first time developed novel acetyl-donating HDAC inhibitors. In this study, we report the design, synthesis, in silico docking study, and biological evaluation of acetyl-donating HDAC inhibitors. The exposure of MDA-MB-231 cells with compound 4c significantly promotes the acetylation of α-tubulin and histone H3, which are substrates of HDAC6 and HDAC1, respectively. In silico docking simulation also indicates that compound 4c tightly binds to the deep substrate-binding pocket of HDAC6 by coordinating the active zinc ion in a bidentate manner and forming hydrogen bond interactions with Ser531 and His573 amino acid residues. In particular, compound 4c (GI₅₀?=?147 μM) affords the significant enhancement of anti-proliferative effect on MDA-MB-231 cells, compared with its parent compound 2c (GI₅₀?>?1000 μM) and acetyl-donating group deficient compound 6 (GI₅₀?=?554 μM). Overall, compound 4c presents a novel strategy for developing acetyl-donating HDAC inhibitors.     

Long-Acting Profile of 4 Drugs in 1 Anti-HIV Nanosuspension in Nonhuman Primates for 5 Weeks After a Single Subcutaneous Injection

Daily oral antiretroviral therapy regimens produce limited drug exposure in tissues where residual HIV persists and suffer from poor patient adherence and disparate drug kinetics, which all negatively impact outcomes. To address this, we developed a tissue- and cell-targeted long-acting 4-in-1 nanosuspension composed of lopinavir (LPV), ritonavir, tenofovir (TFV), and lamivudine (3TC). In 4 macaques dosed subcutaneously, drug levels over 5 weeks in plasma, lymph node mononuclear cells (LNMCs), and peripheral blood mononuclear cells (PBMCs) were analyzed by liquid chromatography–tandem mass spectrometry. Plasma and PBMC levels of the active drugs (LPV, TFV, and 3TC) were sustained for 5 weeks; PBMC exposures to LPV, ritonavir, and 3TC were 12-, 16-, 42-fold higher than those in plasma. Apparent T_1/2z of LPV, TFV, and 3TC were 219.1, 63.1, and 136.3 h in plasma; 1045.7, 105.9, and 127.7 h in PBMCs. At day 8, LPV, TFV, and 3TC levels in LNMCs were 4.1-, 5.0-, and 1.9-fold higher than in those in PBMCs and much higher than in plasma. Therefore, 1 dose of a 4-drug nanosuspension exhibited persistent drug levels in LNMCs, PBMCs, and plasma for 5 weeks. With interspecies scaling and dose adjustment, this 4-in-1 HIV drug-combination could be a long-acting treatment with the potential to target residual virus in tissues and improve patient adherence.     

Health service utilization,unmet healthcare needs,and the potential of telemedicine services among Korean expatriates

Background

With the significant growth of migration and expatriation, facilitated by increased global mobility, the number of Koreans living abroad as of 2016 is approximately 7.4 million (15% of the Korean population). Healthcare utilization or health problems, especially among expatriates in developing countries, have not been well researched despite the various health risks these individuals are exposed to. Consequently, we identified the health utilization patterns and healthcare needs among Korean expatriates in Vietnam, Cambodia, and Uzbekistan.

Methods

This cross-sectional survey examined 429 Korean expatriates living in Vietnam (n?=?208), Cambodia (n?=?60), and Uzbekistan (n?=?161) who had access to the Internet and were living abroad for at least 6?months. A 67-item questionnaire was used, and feedback was received via an online survey program. Stepwise logistic regression analyses were performed to evaluate factors associated with unmet healthcare needs and preferences of certain type of telemedicine.

Results

We found that 45.5% (195/429) of respondents had used medical services in their country of stay. Among those who visited health institutions >?3 times, the most popular choice was general hospitals (39.4%, 15/38); however, they initially visited Korean doctors’ or local doctors’ offices. The most essential criteria for healthcare service facilities was a “skilled professional” (39.3%, 169/429), 42% wanted a health program for chronic disease management, and 30% wanted specialized internal medicine. A substantial number wanted to access telemedicine services and were willing to pay for this service. They were particularly interested in experts’ second opinion (61.5%, 264/429) and quick, 24-h medical consultations (60.8%, 261/429). Having unmet healthcare needs and being younger was strongly associated with all types of telemedicine networks.

Conclusions

Nearly half of the expatriates in developing countries had unmet healthcare needs. Telemedicine is one potential solution to meet these needs, especially in developing countries.

     

Initial combination therapy with vildagliptin plus metformin in drug-naïve patients with T2DM: a 24-week real-life study from Asia

Aims: To assess the effectiveness and safety of vildagliptin/metformin initial combination therapy in drug-naïve patients with type 2 diabetes mellitus (T2DM).

Methods: INITIAL was a 24-week prospective, observational study in T2DM patients with glycated hemoglobin (HbA1c)?≥?7.5%, and prescribed vildagliptin/metformin as initial combination therapy. The primary endpoint was change in HbA1c from baseline to week 24. Key secondary endpoints were HbA1c change from baseline to week 12, proportion of patients achieving HbA1c ≤7.0%, change in body weight at 12 and 24 weeks, change in HbA1c by sub-groups (baseline HbA1c, age, body mass index [BMI], dosage strength, co-morbidities) from baseline to week 24, and safety.

Results: A total of 532 patients were enrolled. The mean age, HbA1c, and BMI were 49.6?±?11.27 years, 9.3?±?1.57%, and 26.7?±?4.50?kg/m², respectively. Cardiovascular risk factors present at baseline were dyslipidemia (30.1%), hypertension (29.7%), and obesity (20.9%). The mean reductions in HbA1c from baseline to week 12 (?1.6?±?1.59%) and 24 (?1.9?±?1.70%) were statistically significant (p?Conclusions: Overall, in a relatively young drug-naïve T2DM Asian study population with high baseline HbA1c and often associated with cardiovascular risk factors, vildagliptin/metformin combination therapy was associated with significant and clinically relevant HbA1c reduction from baseline. This effect was seen at week 12, was maintained over 24 weeks, and was accompanied by good tolerability.