Oral Biopharmaceutics and In vitro Pharmacokinetics of Commercially Available Pharmaceutical Formulations of Paracetamol: Implications in Paediatric Medicine

Aim: This study aimed to compare the oral pharmacokinetics of different paediatric paracetamol dosage forms that are commercially available in Nigeria.

Study Design: Experimental.

Place and Duration of Study: Faculty of Pharmaceutical Sciences, Enugu State University of Science and Technology, between March and December 2023

Methodology: The study used the regular in vitro dialysis membrane method to predict the in vivo drug release of commercially available paracetamol syrups (n=5) and dispersible tablets (n=5) in the Nigerian market. The sink condition followed the Conventional USP dissolution method, using a dialysis membrane sac. The drug samples were studied in simulated salivary fluid of pH 7.4, simulated gastric fluid of pH 1.2, and simulated intestinal fluid of pH 6.5 over 8 hours to simulate their passage in the gastrointestinal tract. At predetermined time intervals, 5 ml of the dissolution medium was drawn out from the system, diluted appropriately and its absorbance measured against a suitable blank at λ = 250 nm using a UV/Vis Spectrophotometer, while a fresh volume of 5 ml of dissolution medium was introduced into the dissolution vessel after each withdrawal.

Results: Syrup dosage forms showed a faster drug release kinetics, based on their values. Kinetic parameters obtained from the linear regression analysis of the in vitro release resulted in a zero-order release kinetics, with for paracetamol paediatric syrups, and for tablets. Two-way ANOVA test of the AUC of dosage forms showed that the time required to elicit therapeutic response was extremely significant (F=44.37, DFn=3, DFd= 32 and P-value < 0.0001).

Conclusion: The comparative in vitro pharmacokinetic study of paracetamol dosage forms revealed that the paediatric syrup formula has a better release kinetics than the scaled down adult formula.