title: Fast and sensitive liquid chromatography/electrospray mass spectrometry method to study ocular penetration of EDL-155, a novel antitumor agent for retinoblastoma in rats.
abstract: Our group has used the tetrahydroisoquinoline derivative EDL-155 to treat glioblastoma in animal models and it is currently being evaluated in the treatment of ocular cancers. The purpose of this study was to develop a rapid and sensitive liquid chromatography and tandem mass spectrometry (LC-MS/MS) method to study the plasma and vitreous humor disposition of EDL-155 in rats. Animals received a single periocular injection of EDL-155 (20 mg/kg). Animals were sacrificed at specified times (5, 60, 120, 240 and 360 min) and plasma and vitreous humor samples were obtained. EDL-155 was isolated by protein precipitation and the extracts were analyzed by reversed-phase high-pressure liquid chromatography (HPLC) with MS/MS detection. A structurally similar analog was used as internal standard (IS). The chromatographic run time was 3.5 min per injection. The mass spectrometer was operated in positive-ion, multiple reaction monitoring (MRM) mode. The mass transitions monitored were m/z332.2 --> 167.2 (EDL-155) and m/z391.2 --> 200.2 (IS). The lower limit of quantification (LLOQ) was 0.1 ng/ml in both vitreous humor and plasma. The method was validated for selectivity, linearity, accuracy and precision in rat vitreous humor and partially validated for accuracy and precision in rat plasma. The ion suppression, recovery and stability of the analyte in the biological matrix were also tested. The assay was rapid, sensitive and robust enough to support EDL-155 ocular penetration studies in a rodent model of intraocular cancer. Application of this method revealed that EDL-155 was rapidly passed into the vitreous humor following periocular administration. Further, vitreous humor exposure exceeded systemic exposure by approximately sevenfold. High local concentrations coupled with minimal systemic exposure supports further testing of EDL-155 as localized therapy for intraocular cancers.
authors.affiliation: Department of Pharmaceutical Sciences, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
authors.forename: Suma
authors.initials: S
authors.lastname: Ramagiri
authors.forename: Fei
authors.initials: F
authors.lastname: Ma
authors.forename: Hari
authors.initials: H
authors.lastname: Kosanam
authors.forename: XiangDi
authors.initials: X
authors.lastname: Wang
authors.forename: Renukadevi
authors.initials: R
authors.lastname: Patil
authors.forename: Duane D
authors.initials: DD
authors.lastname: Miller
authors.forename: Eldon
authors.initials: E
authors.lastname: Geisert
authors.forename: Charles R
authors.initials: CR
authors.lastname: Yates
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000032:analysis / Q000097:blood / Q000493:pharmacokinetics*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004355:Drug Stability; D016014:Linear Models; D051381:Rats; D017208:Rats, Wistar; D012015:Reference Standards; D015203:Reproducibility of Results; D012175:Retinoblastoma / Q000188:drug therapy; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D044005:Tetrahydroisoquinolines / Q000008:administration & dosage / Q000032:analysis / Q000097:blood / Q000493:pharmacokinetics*; D014822:Vitreous Body / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; C529597:EDL-155; D044005:Tetrahydroisoquinolines