title: An extended-release formulation of methotrexate for subcutaneous administration.
abstract: Methotrexate is a cell-cycle phase-specific antimetabolite that requires prolonged exposure for optimal efficacy. However, the in vivo half-life is short, and repeated administrations are required for optimal efficacy. Methotrexate was encapsulated into a lipid-based drug-delivery system to create an extended-release formulation (Depo/methotrexate) for subcutaneous administration. Pharmacokinetics and efficacy studies were done in BDF1 mice. Depo/methotrexate increased the methotrexate plasma half-life by a factor of 190, from 0.53 to 100 h. Plasma peak levels of the encapsulated drug were 120-fold lower than those of unencapsulated methotrexate, whereas the AUCs (areas under the concentration-time curve) were similar. As a consequence of the extended drug release, the single-dose potency of methotrexate against the L1210 leukemia model was increased by a factor of about 130 without producing significant changes in the therapeutic index. In conclusion, Depo/methotrexate appears to have potential usefulness as an extended-release formulation of methotrexate.
authors.affiliation: UCSD Cancer Center, University of California, San Diego, La Jolla 92093-0812.
authors.forename: A
authors.initials: A
authors.lastname: Bonetti
authors.forename: E
authors.initials: E
authors.lastname: Chatelut
authors.forename: S
authors.initials: S
authors.lastname: Kim
mesh_terms: D000818:Animals; D003692:Delayed-Action Preparations; D005260:Female; D007279:Injections, Subcutaneous; D008727:Methotrexate / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D051379:Mice; D008811:Mice, Inbred DBA
chemical_list: D003692:Delayed-Action Preparations; D008727:Methotrexate