To cover the unpleasant taste of amoxicillin (250 mg), maize starch (baby food) and milk chocolate were co-formulated. The raw materials and the final formulations were characterized by means of Dynamic Light Scattering (DLS), Differential Scanning Calorimetry (DSC) and Fourier-Transform Infrared (FT-IR) spectroscopy. To evaluate the taste masking two different groups of volunteers were used, according to the Ethical Research Committee of the Aristotle University of Thessaloniki. The optimization of excipients' content in the tablet was determined by experimental design methodology (crossed D-optimal). Due to the matrix complexity, amoxicillin was extracted using liquid extraction and analyzed isocratically by HPLC. The developed chromatographic method was validated (%Recovery 98.7-101.3, %RSD = 1.3, LOD and LOQ 0.15 and 0.45 μg mL-1 respectively) according to the International Conference on Harmonization (ICH) guidelines. The physicochemical properties of the tablets were also examined demonstrating satisfactory quality characteristics (diameter: 15 mm, thickness: 6 mm, hardness <98 Newton, loss of mass <1.0%, disintegration time ∼25min). Additionally, dissolution (%Recovery >90) and in vitro digestion tests (%Recovery >95) were carried out. Stability experiments indicated that amoxicillin is stable in the prepared formulations for at least one year (%Recovery <91).
Keywords: Amoxicillin; HPLC; chocolate formulation; experimental design; in vitro digestion.