The Impact of Alkyl-Chain Purity on Lipid-Based Nucleic Acid Delivery Systems - Is the Utilization of Lipid Components with Technical Grade Justified?

The physicochemical properties and transfection efficacies of two samples of a cationic lipid have been investigated and compared in 2D (monolayers at the air/liquid interface) and 3D (aqueous bulk dispersions) model systems using different techniques. The samples differ only in their chain composition due to the purity of the oleylamine (chain precursor). Lipid 8 (using the oleylamine of technical grade for cost-efficient synthesis) shows lateral phase separation in the Langmuir layers. However, the amount of attached DNA, determined by IRRAS, is for both samples the same. In 3D systems, lipid 8 p forms cubic phases, which disappear after addition of DNA. At physiological temperatures, both lipids (alone and in mixture with cholesterol) assemble to lamellar aggregates and exhibit comparable DNA delivery efficiency. This study demonstrates that non-lamellar structures are not compulsory for high transfection rates. The results legitimate the utilization of oleyl chains of technical grade in the synthesis of cationic transfection lipids.

Theory and practice of pharmacopoeial control of quality of drugs and excipients VIII. End-point indication and other conditions for the titration of primary aromatic amines in the European Pharmacopoeia (Ph. Eur.).

Indication of the equivalence point for the titration of primary aromatic amines (sulphonamides, etc.) with sodium nitrite solution according to Ph. Eur. (2.5.8) is performed electrometrically or using a prescribed indicator, the electrometric method not being specified. Better reproducibility of the assay results would add to Ph. Eur. the electrometric method to be used for the indication and suitable electrodes for it. The authors of the paper propose a potentiometric indication, which is in Ph. Eur. widely used. Further, they propose to consider whether in Article 2.5.8. Ph. Eur. indications using an indicator as an alternative to the instrumental indication required. The titration in the presence of hydrochloric acid favourably affects the addition of potassium bromide, cooling the solution prior to the titration prescribed by Ph. Eur. is not needed.

Half of hospitals in England fail to meet mandatory food standards, report reveals.

A new report reveals almost half of hospitals in England are failing to meet mandatory food standards two years after the government introduced them.

Subsecond absolute quantitation of amine metabolites using isobaric tags for discovery of pathway activation in mammalian cells.

The absolute quantitation of amine metabolites from mammalian cell samples was achieved by combining amine standards, isobaric tags, and capillary liquid chromatography (LC) tandem mass spectrometry (MS/MS). Our approach allowed 32 specific amines to be analyzed within a single chromatographic run, with the generation of the calibration curve and absolute quantitation of each analyte taking less than 900 ms. Using this strategy, we determined the amine response of human aortic endothelial cells (HAECs) from a glucose challenge. The observed changes of the absolute concentration of these metabolites implied eight enzymatic reactions may change efficiency upon glucose treatment. Five of these reactions have been previously reported as being up-regulated in diabetic conditions. The remaining three reactions were analyzed by measuring the expression of these enzymes, with 66% showing increases. Our data indicate that rapid determination of absolute quantitation is useful in determining novel pathway activation. Furthermore, even though we determined the absolute quantity of 32 metabolites here, the number of analytes that can be measured by this method is limited mainly by commercial availability of amine standards.

Modified QuEChERS purification and Fe3O4 nanoparticle decoloration for robust analysis of 14 heterocyclic aromatic amines and acrylamide in coffee products using UHPLC-MS/MS.

Based on QuEChERS dispersed purification, Fe3O4 nanoparticle decoloration and UHPLC-MS/MS, a robust and sensitive method was established for simultaneous analysis of 14 heterocyclic aromatic amines (HAAs) and acrylamide (AA) in coffee products. Sample was extracted by 90% acetonitrile water (v/v), dispersed with primary secondary amine (PSA) and further purified with Fe3O4 nanoparticle. Then, 15 analytes were detected using ESI positive ion under MRM mode. Good linearity was observed for all analytes in the range of 0.2-100 µg/L with the determination coefficients being above 0.996. Limits of detection (S/N ≥ 3) and limits of quantification (S/N ≥ 10) were in the range of 0.02-0.15 µg/L and 0.2-0.7 µg/L, respectively. The intra-day average recoveries were between 81.6% and 100%, and the intra-day precisions ranged from 4.3% to 9.0%. The inter-day average recoveries were in the range of 81.0-101% with precisions ranging from 5.0% to 7.8%. Results indicated that the combination of PSA and Fe3O4 exhibited superior purification and adsorption effects for removing pigments and acid compounds. Real samples analysis indicated that coffee products were widely contaminated with AA, harman and norharman.

Update in perioperative medicine: practice changing evidence published in 2016.

This summary reviews 18 key articles published in 2016 which have significant practice implications for the perioperative medical care of surgical patients. Due to the multi-disciplinary nature of the practice of perioperative medicine, important new evidence is published in journals representing a variety of medical and surgical specialties. Keeping current with the evidence that drives best practice in perioperative medicine is therefore challenging. We set out to identify, critically review, and summarize key evidence which has the most potential for practice change. We integrated the new evidence into the existing body of medical knowledge and identified practical implications for real world patient care. The articles address issues related to anticoagulation, transfusion threshold, immunosuppressive medications, postoperative delirium, myocardial injury after noncardiac surgery, postoperative pain management, perioperative management of antihypertensives, perioperative fasting, and perioperative diabetic control.

Microwave-assisted on-spot derivatization for gas chromatography-mass spectrometry based determination of polar low molecular weight compounds in dried blood spots.

Dried blood spot (DBS) sampling and analysis is increasingly being applied in bioanalysis. Although the use of DBS has many advantages, it is also associated with some challenges. E.g. given the limited amount of available material, highly sensitive detection techniques are often required to attain sufficient sensitivity. In gas chromatography coupled to mass spectrometry (GC-MS), derivatization can be helpful to achieve adequate sensitivity. Because this additional sample preparation step is considered as time-consuming, we introduce a new derivatization procedure, i.e. "microwave-assisted on-spot derivatization", to minimize sample preparation of DBS. In this approach the derivatization reagents are directly applied onto the DBS and derivatization takes place in a microwave instead of via conventional heating. In this manuscript we evaluated the applicability of this new concept of derivatization for the determination of two polar low molecular weight molecules, gamma-hydroxybutyric acid (GHB) and gabapentin, in DBS using a standard GC-MS configuration. The method was successfully validated for both compounds, with imprecision and bias values within acceptance criteria (<20% at LLOQ, <15% at 3 other QC levels). Calibration lines were linear over the 10-100µg/mL and 1-30µg/mL range for GHB and gabapentin, respectively. Stability studies revealed no significant decrease of gabapentin and GHB in DBS upon storage at room temperature for at least 84 days. Furthermore, DBS-specific parameters, including hematocrit and volume spotted, were evaluated. As demonstrated by the analysis of GHB and gabapentin positive samples, "microwave-assisted on-spot derivatization" proved to be reliable, fast and applicable in routine toxicology. Moreover, other polar low molecular weight compounds of interest in clinical and/or forensic toxicology, including vigabatrin, beta-hydroxybutyric acid, propylene glycol, diethylene glycol, 1,4-butanediol and 1,2-butanediol, can also be detected using this method.

Mycobactericidal and tuberculocidal activity of Korsolex AF, an amine detergent/disinfectant product.

The mycobactericidal and tuberculocidal activities of Korsolex AF against Mycobacterium tuberculosis, Mycobacterium avium-Mycobacterium intracellulare (MAI), Mycobacterium kansasii and Mycobacterium chelonae were determined using quantitative suspension and carrier tests. The effects of organic load and hard water were also considered. A clinical isolate of MAI was the most resistant of the four test organisms. A 2% solution had good mycobactericidal and tuberculocidal activities after 30 min of exposure. Although further evaluation using European standard tests is necessary, we conclude that Korsolex AF appears to be a promising product for the disinfection of hospital instruments contaminated with mycobacteria.

A retention index library for commonly encountered drugs and metabolites using tri-n-alkylamines as reference compounds, nitrogen-phosphorus detectors, and dual capillary chromatography.

The retention index system is a reproducible means for the identification of drugs in toxicology samples analyzed by gas chromatography with flame ionization detectors. Nitrogen-phosphorus (NP) detectors do not respond well to the standard n-alkanes, which lack nitrogen and phosphorus groups and which are used to obtain the Kovats index. A method is presented that creates a retention index library based upon a homologous series of tri-n-alkylamines for a series of 125 drugs and metabolites. Standards were analyzed under temperature programmed conditions by simultaneous dual column chromatography using a 5% phenyl and a 50% phenyl methyl silicone fused-silica capillary column. By increasing the hydrogen and air flows to the NP detectors, the Kovats indices were calculated on the system using the n-alkanes C8 through C32. Tri-n-alkylamine indices calculated under the same conditions were compared to the Kovats indices for 14 drugs on the 5% phenyl column and for 12 drugs on the 50% phenyl column. The correlation was found to be linear. The Kovats indices on the 5% phenyl column were compared to previously reported values and found to be consistent.

Urine drug testing of chronic pain patients. IV. prevalence of gabapentin and pregabalin.

Gabapentin and pregabalin are well established for the treatment of seizures and neuropathic pain. Both drugs are eliminated primarily unchanged by renal excretion. As part of an ongoing research program to improve and expand drug testing methods for compliance monitoring of pain patients, the prevalence and concentrations of gabapentin and pregabalin in urine specimens from chronic pain patients were determined by a validated liquid chromatography-tandem mass spectrometry assay. The study was approved by an Institutional Review Board. A total of 57,542 urine specimens from 231 pain clinics located in 19 states were analyzed over the period of November 24, 2009, through May 2010. The limit of quantitation (LOQ) and upper LOQ of the assays for both drugs were 2.5 and 1000 µg/mL, respectively. Gabapentin was identified in 7013 specimens (12.2% prevalence), and pregabalin was identified in 4799 patients (8.3% prevalence). Generally, gabapentin concentrations were more than twofold higher than pregabalin, consistent with their relative potencies. Interestingly, both drugs were found in specimens from 249 patients, likely representing switching of prescriptions by the prescriber.

Effects of genetic variation in the novel organic cation transporter, OCTN1, on the renal clearance of gabapentin.

Gabapentin is an anticonvulsant that is widely prescribed for epilepsy and other neuropathic disorders. The pharmacokinetics, particularly the absorption and renal elimination, of gabapentin appear to involve membrane transporters. In this study, we tested the hypothesis that organic cation transporter 1 (OCTN1), a multispecific transporter expressed at the apical membrane in intestine and kidney, plays a role in gabapentin pharmacokinetics and that the common variant of OCTN1, OCTN1-L503F, contributes to variation in the pharmacokinetics of the drug. We observed that OCTN1 facilitates the Na+-independent transport of gabapentin, and that the OCTN1-L503F variant is deficient in gabapentin transport activity in stably transfected HEK-293 cells (fourfold enhanced uptake of gabapentin by OCTN1-503L vs twofold enhanced uptake by OCTN1-L503F, compared to mock-transfected cells). In clinical studies, we found that in subjects homozygous for the L503F variant, gabapentin renal clearance (CL(R)) approximates the glomerular filtration rate (mean+/-SE: 110+/-12 ml/min, n=9), whereas in subjects homozygous for the reference allele, gabapentin undergoes net secretion in the kidney (141+/-7.8 ml/min, n=11, P<0.05). Creatinine clearance and OCTN1 genotype accounted for 56% of the variation in CL(R) and were the only significant predictors of CL(R) (P<0.05). Importantly, OCTN1 genotype was the only significant predictor of net secretion of gabapentin (P<0.008). Oral bioavailability of gabapentin was not affected by OCTN1 genotype. We conclude that OCTN1 contributes to active tubular secretion of gabapentin, and that this effect may be diminished or absent in individuals carrying the OCTN1-L503F polymorphism. These results provide clinical evidence of the role of genetic variation in renal drug transporters in active drug secretion in vivo.