Determination of Levetiracetam in Human Plasma by Dispersive Liquid-Liquid Microextraction Followed by Gas Chromatography-Mass Spectrometry

Abstract

Levetiracetam (LEV) is an antiepileptic drug that is clinically effective in generalized and partial epilepsy syndromes. The use of this drug has been increasing in clinical practice and intra- or -interindividual variability has been exhibited for special population. For this reason, bioanalytical methods are required for drug monitoring in biological matrices. So this work presents a dispersive liquid-liquid microextraction method followed by gas chromatography-mass spectrometry (DLLME-GC-MS) for LEV quantification in human plasma. However, due to the matrix complexity a previous purification step is required. Unlike other pretreatment techniques presented in the literature, for the first time, a procedure employing ultrafiltration tubes Amicon® (10 kDa porous size) without organic solvent consumption was developed. GC-MS analyses were carried out using a linear temperature program, capillary fused silica column, and helium as the carrier gas. DLLME optimized parameters were type and volume of extraction and dispersing solvents, salt addition, and vortex agitation time. Under chosen parameters (extraction solvent: chloroform, 130 μL; dispersing solvent: isopropyl alcohol, 400 μL; no salt addition and no vortex agitation time), the method was completely validated and all parameters were in agreement with the literature recommendations. LEV was quantified in patient's plasma sample using less than 550 μL of organic solvent.

Therapeutic drug monitoring of levetiracetam: Method validation using high-performance liquid chromatography-ultraviolet detector technique and usefulness in patient care setting

“…For example, PPP procedure can result in signal suppression when LC/MS is used because of the presence of a precipitation agent, coprecipitation of interfering species, and lack of selectivity; SPE procedure gives interference, bad recovery with high standard deviation, is complicated, time consuming, and expensive; cartridges used for the extraction are relatively expensive with the risk of carryover and cross-contamination; and most of the chromatography techniques have tedious and time-consuming sample preparation procedures. [ 6 7 8 9 10 ]…”

“…[ 14 ] We developed our method for the serum estimation of levetiracetam modifying HPLC techniques mentioned in literature. [ 5 6 7 8 9 ] Liquid–liquid phase extraction method was used to prepare the samples prior to the running on the analytic HPLC-UV system. Theophylline was employed as the internal standard (IS) to control the extraction procedure.…”

“…Some of these procedures are complicated, time consuming, expensive, and lack selectivity. [ 6 7 8 9 10 ]…”

Review on bioanalytical and analytical method development of Antiepileptic racetams

“…Another GC method was applied for determination of LEV in human plasma after dispersive liquid-liquid microextraction. The method was based on using a linear temperature program, capillary fused silica column, and helium as the carrier gas (Alcantara et al, 2016). Alvarez et al (Alvarez-Freire, Rodríguez, Barrera, Cabarcos-Fernandez, & Tabernero-Duque, 2021) developed GC/MS method for the determination of LEV in human plasma, the determination was performed in selected ion monitoring mode using deuterated levetiracetam as internal standard.…”

Untitled

“…As a result, it is able to form sedimented phase in the bottom of the tube after phase separation [3]. Chlorinated solvents such as chloroform, chlorobenzene, carbon tetrachloride, and tetrachloroethylene are commonly selected as extraction solvent as they fulfil such requirements [17]. These chlorinated solvents show the advantages in DLLME such as producing high enrichment factor, short extraction time, ease of operation and high sensitivity [18][19][20].…”