title: Stability and analysis of 2-chloro-2'-deoxyadenosine, 2-chloro-2'-arabino-fluoro-2'-deoxyadenosine and 2-chloroadenine in human blood plasma.
abstract: Cladribine (2-chloro-2'-deoxyadenosine, CdA) is a purine nucleoside analog with activity against lymphoproliferative and autoimmune disorders. 2-Chloro-2'-arabino-fluoro-2'-deoxyadenosine (CAFdA), a derivative of CdA with better acid stability, shows a similar in vitro spectrum of activity as CdA. 2-Chloroadenine (CAde) is the major catabolite of both CdA and CAFdA. We have developed a high performance liquid chromatography method to measure CdA, CAFdA and their metabolite CAde in plasma. This method employees an internal standard, chloroadenosine (CAdo), and a C8 solid-phase extraction to isolate and concentrate the substances. Chromatographic separation was achieved using a C8 reverse-phase column, with UV detection at 265 nm, which gives a limit of detection of 1 nmol/l for all substances. The method was reproducible with intra- and inter-assay coefficients of variations below 6% at 50 nmol/l and at 5 nmol/l below 23%. The average recoveries of CdA, CAde, CAFdA and the internal standard were higher than 70%. Stability studies of authentic patient samples show that samples containing CdA should be kept in a refrigerator or on ice to prevent degradation. Plasma containing CAde should not be kept at -20 degrees C for longer than 10 weeks before analysis. CdA and CAFdA remain almost stable during storage at -20 degrees C for 12 weeks.
authors.affiliation: Department of Clinical Pharmacology, Karolinska Hospital, Stockholm, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Lindemalm
authors.forename: F
authors.initials: F
authors.lastname: Albertioni
authors.forename: J
authors.initials: J
authors.lastname: Liliemark
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000097:blood; D000227:Adenine Nucleotides; D000368:Aged; D000970:Antineoplastic Agents / Q000097:blood*; D001087:Arabinonucleosides / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D017338:Cladribine / Q000097:blood*; D000077866:Clofarabine; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000227:Adenine Nucleotides; D000970:Antineoplastic Agents; D001087:Arabinonucleosides; C069484:2-chloroadenine; D017338:Cladribine; D000077866:Clofarabine; D000225:Adenine