Abstract

Background: Cytarabine (CA) is used to treat dogs with meningoencephalomyelitis of unknown etiology (MUE) by subcutaneous (SC) or intravenous (IV) administration.
Aim: The objective was to investigate transdermal iontophoresis and rectal administration as alternative routes of CA delivery.
Methods: Two client-owned dogs with MUE were studied. The ActivaPatch® IONTOGO™ 12.0 iontophoresis drug delivery system delivered 200 mg/m^2 CA transdermally. Blood samples were collected by sparse sampling technique after initiation of the device. At another visit, 100 mg/m^2 CA was administered rectally. Blood samples were collected by sparse sampling technique after administration. Plasma CA concentrations were measured by high-pressure liquid chromatography (HPLC).
Results: The concentration of plasma CA after transdermal and rectal administration was below the limits of quantification (0.1ug/mL) in all samples suggesting inadequate bioavailability with transdermal and rectal administration.
Conclusion: Transdermal and rectal CA administration are not reasonable alternative routes of delivery.

Key words: dog, meningoencephalitis, cytarabine, bioavailability