Natchaya VanwongSantirat PrommasApichaya PuangpetchYaowaluck HongkaewNopadol NuntamoolChalitpol Na NakornNattawat NgamsamutPenkhae LimsilaChonlaphat SukasemMahidol UniversityFaculty of Medicine, Ramathibodi Hospital, Mahidol UniversityThailand Ministry of Public Health2018-12-112019-03-142018-12-112019-03-142016-11-01Journal of Clinical Laboratory Analysis. Vol.30, No.6 (2016), 1236-124610982825088780132-s2.0-84977588619https://repository.li.mahidol.ac.th/handle/20.500.14594/42758© 2016 Wiley Periodicals, Inc. 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.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyHealth ProfessionsMedicineArticleSCOPUS10.1002/jcla.22009