Development and Validation of Liquid Chromatography/Tandem Mass Spectrometry Analysis for Therapeutic Drug Monitoring of Risperidone and 9-Hydroxyrisperidone in Pediatric Patients with Autism Spectrum Disorders.

BACKGROUND: Risperidone (RIS) is a widely used atypical antipsychotic drug. We developed and validated a sensitive and accurate LC-MS/MS method, which requires a small-volume of plasma and small-volume injection for measurement of RIS levels in ASD pediatric patients. We also investigated the relationship between RIS levels and RIS dosages, including prolactin levels.

METHOD: Blood samples were processed by protein precipitation extraction. Only 1 μl of sample was injected. Plasma samples were separated on a C18 column (4.6 cm × 50 mm; 1.8 μm particle size). Detection was by MS-MS with an analytical run time of 6 min.

RESULTS: The inter-day accuracy of RIS was 101.33-107.68% and 95.24-103.67% for 9-OH-RIS. The inter-day precision of RIS was ≤7.27% CV and ≤7.41% CV for 9-OH-RIS. The extraction recovery of RIS and 9-OH-RIS were 95.01 ± 7.31-112.62 ± 7.50% and 90.27 ± 11.15-114.00 ± 10.35%, respectively. This method was applied in the therapeutic drug monitoring of ASD pediatric patients. Higher RIS dosage has a tendency to produce higher RIS plasma levels. The high RIS plasma levels have a tendency to produce hyperprolactinemia.

CONCLUSION: The determination of RIS in individual patients might be clinically useful for monitoring and prediction of treatment response.