High-performance liquid chromatographic analysis of lacosamide in canine serum using ultraviolet detection: application to pre-clinical pharmacokinetics in dogs

Selective quantification of lacosamide in human plasma using UPLC-MS/MS: Application to pharmacokinetic study in healthy subjects with different doses

A practical, sensitive, and robust UPLC-MS/MS method was developed and validated to quantify lacosamide in human plasma. A simple one-step protein precipitation was used to extract lacosamide and labeled lacosamide-13C, D3 as an internal standard (IS) from 150-μL plasma. The extracts were analyzed on an Eclipse Plus C18 column (50 × 2.1 mm, 1.8 μm) using 0.1% formic acid in water and methanol:acetonitrile (50:50, v/v) under gradient conditions. The extracts were quantified on LCMS-8040 using electrospray ionization source operated in positive ionization and multiple reaction monitoring modes. The method showed good linearity from 0.02 to 20 μg/mL, which was adequate to cover lacosamide concentration assayed in formulations with different strengths. The bioanalytical assay was fully validated as per current regulatory guidelines. The intra-batch and inter-batch precision values of lacosamide were less than 4.6%. Lacosamide was found to be stable at different storage conditions. The extraction recoveries and IS-normalized matrix factors for lacosamide ranged from 97.17 to 99.68% and from 0.973 to 1.012, respectively. The validated method was successfully applied to a pharmacokinetic study with three lacosamide formulations (50, 100, and 200 mg) in 36 healthy subjects. The assay reliability was determined by reanalysis of 81 subject samples.

Green gas chromatographic stability-indicating method for the determination of Lacosamide in tablets. Application to in-vivo human urine profiling

A direct, eco-friendly, stability-indicating GC method was developed for the determination of Lacosamide (LCM) in tablet dosage forms in presence of its degradation products as well as in human urine in presence of the co-administered drug Zonisamide (ZON). The assay method in tablets was validated according to the ICH guidelines, while the method for determination of LCM in urine was validated according to FDA; Bioanalytical Method Validation guidance. Linear response (r = 0.9998) was observed over the range of 20-280 μg/mL of LCM, with detection and quantitation limits of 5.871 and 19.57 μg/mL, respectively for the tablet assay method. While (r = 0.9999) was observed over the range of 0.5-20 μg/mL of LCM, with detection and quantitation limits of 67 and 233 ng mL^-1, respectively for the urine analysis method. Under various stress conditions, the investigation of LCM forced degradation behaviour was carried out. Furthermore, monitoring of the drug in urine followed by construction of its urine profile was done after the administration of 50 mg tablet of LCM to three healthy volunteers so as to prove the ability of the method to be applied in assaying LCM in human urine. The method showed also successful separation of LCM and the co-administered drug ZON in urine. Finally, the greenness of the method was assessed using National Environmental Methods Index label and Eco scale methods.

Evaluation of Brain Pharmacokinetic and Neuropharmacodynamic Attributes of an Antiepileptic Drug, Lacosamide, in Hepatic and Renal Impairment: Preclinical Evidence

The knowledge of pharmacokinetic and pharmacodynamic properties of antiepileptic drugs is helpful in optimizing drug therapy for epilepsy. This study was designed to evaluate the pharmacokinetic and pharmacodynamic properties of lacosamide in experimentally induced hepatic and renal impairment in seizure animals. Hepatic or renal impairment was induced by injection of carbon tetrachloride or diclofenac sodium, respectively. After induction, the animals were administered a single dose of lacosamide. At different time points, maximal electroshock (MES) seizure recordings were made followed by isolation of plasma and brain samples for drug quantification and pharmacodynamic measurements. Our results showed a significant increase in the area under the curve of lacosamide in hepatic and renal impairment groups. Reduced clearance of lacosamide was observed in animals with renal impairment. Along with pharmacokinetic alterations, the changes in pharmacodynamic effects of lacosamide were also observed in all the groups. Lacosamide showed a significant protection against MES-induced seizures, oxidative stress, and neuroinflammatory cytokines. These findings revealed that experimentally induced hepatic or renal impairment could alter the pharmacokinetic as well as pharmacodynamic properties of lacosamide. Hence, these conditions may affect the safety and efficacy of lacosamide.

A simple and versatile method for microencapsulation of anti-epileptic drugs for focal therapy of epilepsy

Nearly 30% of epilepsy cases cannot be adequately controlled with current medical treatments. The reasons for this are still not well understood, but there is a significant body of evidence pointing to the blood-brain barrier. Resective surgery can provide an alternative method of epilepsy control; however this treatment option is not suitable for most epilepsy sufferers. Local drug delivery through micro-injection to or implantation into the brain provides an innovative approach to bypass the blood-brain barrier for epilepsy treatment. In order to develop effective local delivery systems for anti-epilepsy drug (AED), we have prepared a variety of core-shell microcapsules via electrojetting, where a more hydrophobic polymer shell acts as a physical barrier to control the rate of drug release from the drug-loaded polymeric core. The resulting microcapsules demonstrate highly drug encapsulation efficiency, narrow size distribution and uniform morphology. Moreover, the release rate of AED can be modulated by controlling the morphologies of the core-shell microcapsules.

International Veterinary Epilepsy Task Force consensus proposal: medical treatment of canine epilepsy in Europe

In Europe, the number of antiepileptic drugs (AEDs) licensed for dogs has grown considerably over the last years. Nevertheless, the same questions remain, which include, 1) when to start treatment, 2) which drug is best used initially, 3) which adjunctive AED can be advised if treatment with the initial drug is unsatisfactory, and 4) when treatment changes should be considered. In this consensus proposal, an overview is given on the aim of AED treatment, when to start long-term treatment in canine epilepsy and which veterinary AEDs are currently in use for dogs. The consensus proposal for drug treatment protocols, 1) is based on current published evidence-based literature, 2) considers the current legal framework of the cascade regulation for the prescription of veterinary drugs in Europe, and 3) reflects the authors' experience. With this paper it is aimed to provide a consensus for the management of canine idiopathic epilepsy. Furthermore, for the management of structural epilepsy AEDs are inevitable in addition to treating the underlying cause, if possible.

A sensitive and rapid method for quantification of lacosamide and desmethyl lacosamide by LC-MS/MS

BACKGROUND

Monitoring lacosamide (LCM) helps optimize therapeutic dosing in some clinical settings. We developed a novel LC-MS/MS method for measuring serum LCM and O-desmethyl lacosamide (ODL).

RESULTS/DISCUSSION

The sample preparation was protein precipitation with methanol. The total CV was less than 4.7%. Calibration range was 0.95-30.29 µg/ml and 0.95-30.41 µg/ml while the expanded linear range was 0.41-47.49 µg/ml and 0.34-48.17 µg/ml for LCM and ODL, respectively with analytical accuracy of 87.2-106.0%. 45 random serum samples collected from 23 individuals on either 200 mg/day or 400 mg/day of LCM therapy showed concentrations of 2.2-19.8 µg/ml for LCM and up to 2.5 µg/ml for ODL.

CONCLUSION

A simple and sensitive LC-MS/MS assay was validated for quantification of LCM and ODL in human serum.

A fully validated method for the determination of lacosamide in human plasma using gas chromatography with mass spectrometry: application for therapeutic drug monitoring

A simple gas chromatographic method with mass spectrometry detection was developed and validated for the determination of lacosamide in human plasma. Lacosamide and the internal standard, levetiracetam-d6, were extracted from 200 μL plasma, by a solid-phase extraction through HF Bond Elut C18 columns, and derivatized using N-methyl-N-tert-butyldimethylsilyltrifluoroacetamide with 1% tert-butyldimethylsilylchloride in acetonitrile. The limit of quantification was found to be 0.20 μg/mL and the assay was linear up to 20.0 μg/mL with correlation coefficient ≥0.994. The intra- and interday precision values were <4.1% in terms of relative standard deviation (%) and the values of intra- and interday accuracy were found to be within -7.2 and 5.3% in terms of relative error (%). Absolute recovery of the method for lacosamide was determined at three concentration levels and ranged from 92.5 to 97.6%. The developed method uses small volumes of plasma and proved to be simple, rapid, and sensitive for the determination of lacosamide in plasma. This method can be used in routine every day analysis of plasma samples obtained from patients who follow respective antiepileptic treatment and for the investigation of clinical and forensic cases where lacosamide is involved.