Abstract:
Praziquantel pharmacokinetics studies in schistosomiasis infected children are scarce partly due to
the challenges/complexity of intensive blood sampling in the target population. This study was aimed
to investigate the optimal single sampling time-point for monitoring praziquantel exposure. This was
intensive pharmacokinetic study conducted among 32 Schistosoma mansoni infected children treated
with an oral standard single-dose 40 mg/kg praziquantel. Plasma samples were collected at 0, 1, 2,
4, 6 and 8 h post-praziquantel administration. Quantifcation of praziquantel and its enantiomers (R and S-praziquantel) concentrations was done by Liquid chromatography-tandem mass spectrometer
(LC–MS/MS). The correlation between area under the plasma concentration–time curve from 0 to 8 h
(AUC8) and plasma concentrations at each specifc sampling time-point was determined by Pearson’s
correlation coefcient (r2
). The median age (range) of the study population was 12.5 years (10–17). The
study participants were 17 males and 15 females. Both total praziquantel and its enantiomers (R- and
S-praziquantel) displayed a wide inter-individual pharmacokinetic variability. Regression analysis
indicated that, plasma concentrations collected at 4 h post-dose had a signifcantly highest correlation
with the AUC8 for both total praziquantel (r2 = 0.81, p< 0.001) and S-praziquantel (r2 = 0.84, p< 0.001)
than any other sampling time-point; while for R-praziquantel, plasma concentrations collected at 6 h
sampling time-point had a signifcantly highest correlation with the AUC8 (r2 = 0.79, p< 0.001) than
any other sampling time-point. Four hours sampling time-point post-praziquantel administration is
ideal optimal single sampling time-point for therapeutic monitoring of total praziquantel exposure
while 6 h sampling time-point is suitable for monitoring of a pharmacologically active R-praziquantel
enantiomer.
