The effect of hyperglycemia on the pharmacokinetics of valproic acid studied by high-performance liquid chromatography with electrochemical detection

Component analysis of fat, oil and grease in wastewater: challenges and opportunities

The presence of fat, oil and grease can lead to blockages in sewer lines, pumps, and treatment plant operations, thereby creating health risks and environmental hazards. These deposits primarily consist of fatty acids, triglycerides and soap, among other components. These three main components are hydrophobic and insoluble in water. The composition of FOG can vary significantly depending on the source, such as food service establishments, households, or industrial processes. Several analytical methods, such as chromatographic, gravimetric, chemical and spectroscopic analysis, are used to measure different FOG components. AOAC, Gerber and APHA are the most commonly utilized standardized analytical methods for measuring FOG components. The AOAC and Gerber methods, which use gas chromatography, tend to provide more accurate results compared to other methods. This can be attributed to GC's ability to measure individual fatty acids in FOG samples by separating and quantifying each compound based on its unique chemical properties, such as volatility, polarity and molecular weight. Similarly, high-performance liquid chromatography is capable of measuring glycerides by separating and quantifying them based on their polarity and molecular weight. This article delves into the challenge of accurately measuring FOG concentrations and evaluates various FOG measurement technologies. The study also discusses the need for standardized methods for FOG measurement, highlighting the importance of understanding FOG deposits and the performance of grease interceptors.

Nano optical and electrochemical sensors and biosensors for detection of narrow therapeutic index drugs

For the first time, a comprehensive review is presented on the quantitative determination of narrow therapeutic index drugs (NTIDs) by nano optical and electrochemical sensors and biosensors. NTIDs have a narrow index between their effective doses and those at which they produce adverse toxic effects. Therefore, accurate determination of these drugs is very important for clinicians to provide a clear judgment about drug therapy for patients. Routine analytical techniques have limitations such as being expensive, laborious, and time-consuming, and need a skilled user and therefore  the nano/(bio)sensing technology leads to high interest.

The Effect of Plasma Protein Binding on the Therapeutic Monitoring of Antiseizure Medications

Epilepsy is a widely diffused neurological disorder including a heterogeneous range of syndromes with different aetiology, severity and prognosis. Pharmacological treatments are based on the use, either in mono- or in polytherapy, of antiseizure medications (ASMs), which act at different synaptic levels, generally modifying the excitatory and/or inhibitory response through different action mechanisms. To reduce the risk of adverse effects and drug interactions, ASMs levels should be closely evaluated in biological fluids performing an appropriate Therapeutic Drug Monitoring (TDM). However, many decisions in TDM are based on the determination of the total drug concentration although measurement of the free fraction, which is not bound to plasma proteins, is becoming of ever-increasing importance since it correlates better with pharmacological and toxicological effects. Aim of this work has been to review methodological aspects concerning the evaluation of the free plasmatic fraction of some ASMs, focusing on the effect and the clinical significance that drug-protein binding has in the case of widely used drugs such as valproic acid, phenytoin, perampanel and carbamazepine. Although several validated methodologies are currently available which are effective in separating and quantifying the different forms of a drug, prospective validation studies are undoubtedly needed to better correlate, in real-world clinical contexts, pharmacokinetic monitoring to clinical outcomes.

Nerve conduit based on HAP/PDLLA/PRGD for peripheral nerve regeneration with sustained release of valproic acid

The nerve conduits have been developed for nerve defect repair. However, no artificial conduits have obtained comparable results to autografts to bridge the large gaps. A possible reason for this poor performance may be a lack of sustainable neurotrophic support for axonal regrowth. Previous studies suggested nanocomposite conduits can be used as a carrier for valproic acid (VPA), a common drug that can produce effects similar to the neurotrophic factors. Here, we developed the novel bioabsorbable conduits based on hydroxyapatite/poly d-l-lactic acid (PDLLA)/poly{(lactic acid)-co-[(glycolic acid)-alt-(l-lysine)]} with sustained release of VPA. Firstly, the sustained release of VPA in this conduit was examined by high-performance liquid chromatography. Then Schwann cells were treated with the conduit extracts. The cell metabolic activity and proliferation were assayed by 3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2-tetrazolium bromide and bromodeoxyuridine staining. A 10-mm segment of rat sciatic nerve was resected and then repaired, respectively, using the VPA conduit (Group A), the PDLLA conduit (Group B), or the autografts (Group C). Nerve conduction velocities (NCVs), compound muscle action potentials (CMAPs), and histological staining were assayed following the surgery. The cell metabolic activity and proliferation were significantly increased (p < .05) by the extracts from VPA-conduit extract compared to others. NCVs and CMAPs were significantly higher in Groups A and C than Group B (p < .05). The nerve density of Groups A and C was higher than Group B. There was no significant difference between Groups A and C. Taken together, this study suggested the sustained-release VPA conduit promoted peripheral nerve regeneration that was comparable to the autografts. It holds potential for future use in nerve regeneration.

Simultaneous Determination of Schisandrin and Promethazine with Its Metabolite in Rat Plasma by HPLC-MS/MS and Its Application to a Pharmacokinetic Study

This study aimed to develop a selective, simple, and sensitive HPLC-MS/MS method for the simultaneous determination of schisandrin and promethazine (PMZ) with its metabolite in rat plasma, which was further used for a pharmacokinetic herb-drug interaction study. HPLC-MS/MS analyses were performed on an Agilent Technologies 1290 LC and a 6410 triple quadrupole mass spectrometer. The following parameters, the lower limit of quantification (LLOQ), calibration curve, accuracy, precision, stability, matrix effect, and recovery, were validated. The linear range of the developed method for PMZ, its metabolite promethazine sulfoxide (PMZSO), and schisandrin in rat plasma was 0.5-200 ng/mL (R 2 > 0.995), with an LLOQ of 0.5 ng/mL, which completely met the determination requirements of biosamples. The intra- and interday precision (RSD, %) was below 13.31% (below 16.67% for the LLOQ) in various plasma, whose accuracy (bias, %) was from -8.52% to 11.40%, which were both within an acceptable range. This method was successfully applied to a pharmacokinetic herb-drug interaction study after oral administration of PMZ with or without S. chinensis water extract. The results demonstrated that coadministration with the S. chinensis water extract might affect the pharmacokinetic behaviors of PMZ. In turn, when taken together with PMZ, the pharmacokinetic parameters of schisandrin, the main active component of S. chinensis, were also affected. The method established in the current study was selective, simple, sensitive, and widely available with good linearity, high accuracy and precision, and a stable sample preparation process. Moreover, this analytical method provides a significant approach for the investigation of herb-drug interaction between S. chinensis and PMZ. The potential pharmacokinetic herb-drug interaction of PMZ- and schisandrin-containing preparations should be noted.

Does valproate therapy in epileptic patients contribute to changing atherosclerosis risk factors? The role of lipids and free fatty acids

BACKGROUND

We aimed to demonstrate the relationship between the valproate (VPA) treatment versus lipid and serum free fatty acids (FFAs) profiles to be the potential atherosclerosis risk factor in epileptic patients.

METHODS

Fasting blood samples were taken from 21 adult VPA-treated patients and 21 controls. The profiles of lipids, FFAs, clinical parameters and body mass index (BMI) were evaluated.

RESULTS

No significant differences between the study group and controls were found for any of the studied parameters. However, significant differences in the total cholesterol (CHOL), low-density-lipoprotein cholesterol (LDL), triglycerides, the CHOL/HDL (high-density-lipoprotein cholesterol) ratio, and Atherogenic Index of Plasma were observed for overweight patients when compared to those of normal weight. Patients with uncontrolled epilepsy tended to have significantly lower palmitic acid level than seizure-free patients. Oleic acid was found to be positively correlated with VPA concentration for patients with uncontrolled epilepsy, and with the dose corrected VPA concentration for all the patients. The acid was however negatively correlated with stearic acid for both the controls and the patients with uncontrolled epilepsy. PLS method revealed CHOL, LDL, triglycerides and myristic acid to be positively interrelated for the whole group under the study, whereas these parameters were found to be negatively correlated with VPA concentration, and positively with BMI. Furthermore, high sensitivity C-reactive protein was found to be negatively correlated with palmitic acid levels.

CONCLUSION

Overweight VPA-treated patients are exposed to higher risk of atherosclerosis. Alterations in FFAs are likely to depend on seizures control, and on VPA levels.

Determination of Eicosapentaenoic, Docosahexaenoic, and Arachidonic Acids in Human Plasma by High-Performance Liquid Chromatography with Electrochemical Detection

A high-performance liquid chromatography with electrochemical detection (HPLC-ECD) system was developed for the simultaneous determination of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA) in human plasma. In the present HPLC-ECD system, EPA, DHA, and AA were separated using a reverse-phase C30 column and detected based on the voltammetric reduction of 3,5-di-tert-butyl-1,2-benzoquinone (DBBQ). Chromatographic peak areas were proportional to the concentration of EPA, DHA, and AA from 0.75 μM to 0.1 mM (r > 0.998). The concentrations of EPA, DHA, and AA in plasma from healthy human subjects after overnight fasting were determined, and the ratio of EPA to AA was obtained by the present HPLC-ECD method, which required 40 μL of human plasma and a simple procedure of sample preparation using diethyl ether extraction. Moreover, changes in EPA, DHA, and AA concentrations in a human subject were monitored before and after fish oil supplement administration by the present HPLC-ECD system.