DOI: njcpt.com.ng/101.1.2.25
Corresponding Author: RUKAYYAT BUKOLA OLOYEDE
Department of Pharmaceutical and Medicinal Chemistry, Kaduna State University, Kaduna, Nigeria.
E-mail: rukayyat01@yahoo.com
Abstract
Background: The pharmacokinetic evaluation of risperidone is important due to its importance in the
management of crippling and debilitating mental illnesses in all ages and races, its long dosage regimen, coupled
with reports of inter-individual variations in its pharmacokinetic parameters.
Objective: The aim of this study is to determine the pharmacokinetic profile of risperidone in healthy black
volunteers.
Methods: Eighteen (18) healthy male volunteers were recruited for the pharmacokinetic study. Each subject
received a single dose of risperidone (2 mg) tablet and blood samples were collected at specified intervals (0.25,
0.5, 0.75, 1, 1.5, 2, 3, 4, 5, 6, 8, 12 and 24 hours) and the pharmacokinetic parameters for each volunteer was
generated using the Kinetica 5.0 software by feeding in the extrapolated plasma concentrations.
Results: The mean ± SEM pharmacokinetic parameters observed after oral administration of risperidone (2 mg)
to the 18 healthy human volunteers were; Cmax (ng/ml) = 20.80 ± 1.55, tmax (h) = 1.67 ± 0.11, ka (h-1) = 1.92 ±
0.15, t1/2a (h) = 0.40 ± 0.03, ke (h-1) = 0.61 ± 0.12, t1/2e (h) = 1.99 ± 0.32, AUC0-t (ng.h/ml)= 60.06 ± 0.76,
AUC0-∞ (ng.h/ml) = 71.86 ± 9.52, Vd (L) = 75.83 ± 8.43 and Cl (L/h) = 41.57 ± 6.56.
Conclusion: Large inter-individual differences were observed in some pharmacokinetic parameters especially in
the elimination phase and this can be attributed to differences in hepatic metabolism and protein binding among
the participants.
Keywords: Risperidone, pharmacokinetics, inter-individual variations, metabolism, black volunteers