Rectal Bioavailability of Amoxicillin from Hollow-Type Suppositories: Effect of Chemical Form of Amoxicillin

Rectal drug administration could offer advantages in the delivery of medicines for children by avoiding swallowability issues, improving stability and enabling caregivers. This study aimed to evaluate rectal bioavailability hollow-type suppositories (HTS) understand effect two chemical forms amoxicillin: amoxicillin sodium (AS) or trihydrate (AMT). HTS were prepared incorporating a lipophilic core containing antibiotic with polyethylene glycol (PEG) shell. Formulations characterised vitro, absolute was determined rabbit model, while drug–base interactions evaluated using X-ray diffraction crystallography (XRD), differential scanning calorimetry (DSC) Fourier transform infrared spectroscopy. The vitro release from AMT delayed, taking 27.3 ± 4.9 h 50% compared 1.7 AS HTS, likely due solubility differences between AS. presence orthorhombic anhydrous crystals respective confirmed via XRD DSC. PEG shells able protect when stored at 25 °C/60% RH. Despite difference their rates, similar found both (absolute 68.2 6.6% vs. 72.8 32.2% respectively; p = 0.9682). Both formulations showed little no irritation mucosa following single dose.