RESUMEN
Mycophenolic acid (MPA) is the active metabolite of the prodrug mycophenolate mofetil. In this study, we developed and validated a novel ultra-high performance liquid chromatography (UHPLC) method for the rapid quantification of MPA in plasma from dogs, cats and humans. Following the protein precipitation, calibration standards and quality controls were separated by UHPLC reversed-phase on a 1.5µm 2.1×100mmC18 column and quantified using UV detection at 215nm. The procedure produced a linear curve (r2>0.997) over the concentration range 0.4-50µg/mL and exhibited a high degree of repeatability (CV% <11%). The limit of detection (LOD) and lower limit of quantitation (LLOQ) were 0.1 and ≤0.4µg/mL, respectively and the overall recovery was ≥87%. By combining isocratic conditions with a UHPLC column containing solid core particles, we were able to elute MPA and the internal standard (mycophenolic acid carboxybutoxy ether) within 3.0min. The short total run time makes this method ideal to study the disposition of MPA in large batches of plasma samples and/or monitor plasma drug concentrations, as recommended for patients that require optimized immunosuppression.
Asunto(s)
Química Farmacéutica/métodos , Inmunosupresores/sangre , Ácido Micofenólico/sangre , Administración Intravenosa , Administración Oral , Animales , Gatos , Química Farmacéutica/normas , Cromatografía Líquida de Alta Presión/métodos , Cromatografía Líquida de Alta Presión/normas , Perros , Humanos , Inmunosupresores/administración & dosificación , Inmunosupresores/análisis , Ácido Micofenólico/administración & dosificación , Ácido Micofenólico/análisis , Reproducibilidad de los ResultadosRESUMEN
OBJECTIVE: To evaluate the safety and tolerability of rivaroxaban (RIV), an oral direct factor Xa inhibitory drug, in dogs with presumed primary immune-mediated hemolytic anemia (pIMHA). DESIGN: Prospective, multicenter, positive-controlled, unblinded clinical trial. Client-owned dogs were enrolled between October 2012 and March 2014. SETTING: Private referral centers. ANIMALS: Twenty-four client-owned dogs with pIMHA. Enrolled dogs were randomized in 2 treatment groups to receive by mouth RIV or clopidogrel (CL) and low-dose aspirin (LDA). All dogs were monitored for 90 days from the enrollment in the study. INTERVENTIONS: Enrolled dogs were given a standardized immunosuppressive protocol and RIV or CL and LDA. MEASUREMENTS AND MAIN RESULTS: There was no identifiable adverse drug reaction, evidence of hemorrhage, significant prolongation of prothrombin time or activated partial thromboplastin time, or increase in transfusion requirements associated with RIV therapy compared to CL and LDA in dogs with pIMHA. There was no significant difference between treatment groups with respect to thrombotic events, survival rates to discharge, at 1 month and 3 months from diagnosis. CONCLUSIONS: This study suggests that RIV at a median dose of 0.89 mg/kg by mouth once daily was safe and well tolerated in a small group of dogs with presumed pIMHA able to tolerate oral medications and treated with a standardized immunosuppressive treatment protocol. Conclusions regarding the relative efficacy of RIV as compared to CL and LDA cannot be made due to the small size of the treatment groups and because pharmacodynamic effects were not assessed.