title: Determination of acyclovir in horse plasma and body fluids by high-performance liquid chromatography combined with fluorescence detection and heated electrospray ionization tandem mass spectrometry.
abstract: Two methods are presented for the determination of 'respectively' the plasma protein unbound and total concentration of acyclovir in horse plasma and body fluids: first, a liquid-liquid extraction was performed on plasma, combined with HPLC-fluorescence detection for the total plasma concentration; second a more sensitive method using high-performance liquid chromatography combined with heated electrospray ionization tandem mass spectrometry (LC-HESI-MS/MS) was described for plasma and for body fluids analysis. To obtain the unbound concentration of acyclovir in plasma, a simple deproteinization step using a Microcon filter was performed. Ganciclovir was used as an internal standard. Analysis was carried out on an Inertsil 5 ODS-3 column for the HPLC-fluorescence method. For the LC-HESI-MS/MS method a PLRP-S column was used. The limit of quantification (LOQ) for the total concentration was set at 50 and 2 ng mL(-1) for the HPLC-fluorescence method and the LC-HESI-MS/MS method, respectively. The limit of quantification for the unbound concentration was set at 5 ng mL(-1) and at 2 ng mL(-1) for body fluids. The methods were successfully used to perform pharmacokinetic and clinical studies in horses after intravenous and oral dosage of acyclovir and its prodrug valacyclovir.
authors.affiliation: Department of Pharmacology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium. an.maes@ugent.be
authors.forename: A
authors.initials: A
authors.lastname: Maes
authors.forename: B
authors.initials: B
authors.lastname: Garré
authors.forename: N
authors.initials: N
authors.lastname: Desmet
authors.forename: K
authors.initials: K
authors.lastname: van der Meulen
authors.forename: H
authors.initials: H
authors.lastname: Nauwynck
authors.forename: P
authors.initials: P
authors.lastname: De Backer
authors.forename: S
authors.initials: S
authors.lastname: Croubels
mesh_terms: D000212:Acyclovir / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000032:analysis* / Q000097:blood*; D000284:Administration, Oral; D000818:Animals; D000998:Antiviral Agents / Q000008:administration & dosage / Q000032:analysis / Q000097:blood; D001826:Body Fluids / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005453:Fluorescence; D015774:Ganciclovir / Q000032:analysis; D006736:Horses / Q000097:blood / Q000378:metabolism*; D007262:Infusions, Intravenous / Q000662:veterinary; D016014:Linear Models; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D000077483:Valacyclovir; D014633:Valine / Q000008:administration & dosage / Q000031:analogs & derivatives
chemical_list: D000998:Antiviral Agents; D014633:Valine; D000077483:Valacyclovir; D015774:Ganciclovir; D000212:Acyclovir