Preparation, characterization, and antipyretic activity of paracetamol and β-cyclodextrin inclusion complex

This study prepared a paracetamol-β-cyclodextrin inclusion complex via co-precipitation method to address the structural and organoleptic challenges of high-dose orodispersible films. Characterization using DSC, FTIR, and NMR confirmed successful guest–host interaction, while 1H-NMR established a 1:1 stoichiometry. Importantly, PXRD provides the first molecular evidence of a channel-type crystalline habit, with new diffraction peaks at 2θ = 15.4º, 20.3º, and 24.3º. The complex achieved an encapsulation efficiency of 41.94% ± 4.41%. In vitro dissolution studies revealed a regulated, biphasic drug release of up to 81. 41% ± 9.8% after 60 min and a 30-min dissolution efficiency of 60.06% ± 6.92% (p = 0.003). Furthermore, it demonstrated initial antipyretic activity in brewer’s yeast-induced pyrexia in Sprague–Dawley rats. However, the regulated release from the complex resulted in diminished pharmacologic activity at later stages of the assay compared to neat APAP. These findings identify a critical trade-off between the molecular shielding provided by the complex’s architecture and the kinetic barriers to reaching optimal clinical efficacy. This study establishes a foundational blueprint for stabilizing BCS class III drugs in space-constrained platforms and underscores the necessity of optimizing critical process parameters to increase the therapeutic payload within the ΒCD framework.