beta-cyclodextrin insoluble polymers (beta CDP), a type of hydrogels with a high swelling capacity, can be obtained by crosslinking beta-cyclodextrin (beta CD) with epichlorohydrin. Terbinafine (TB) is an oral and topical antifungal drug that can be housed into the cavity of beta-cyclodextrin, so it seems probable that the drug could interact with the insoluble beta CDP. Different organic molecules can be sorbed on the polymer network and also included within the beta CD cavities, so these hydrogels have potential applications in the pharmaceutical field as drug carriers. In this work, the sorption of TB on beta CDP and the optimal conditions to load the polymer with the drug were studied. Sorption kinetics and Freundlich isotherms of TB on beta CDP at 25A degrees C were obtained and the influence of several parameters on the sorption process of TB was investigated. It was found that a high initial concentration of drug, high TB:beta-CD molar ratios and low ionic strengths were the most favourable conditions. No significant influence of temperature was observed. Moreover, the sorption kinetic profile obtained for terbinafine was compared to that of naftifine, another antifungal agent of similar structure. Terbinafine presented higher affinity for the polymer, according to the higher stability constant of the drug-beta CD inclusion complex. In relation to the release studies from the loaded polymer, 0.1 M HCl was the most favourable medium to allow the release of the drug.

Terbinafine (TB) is an allylamine derivative used as oral and topical antifungal agent. The physicochemical properties of the complexes between TB and different cyclodextrins (CDs): alpha-CD, beta-CD, hydroxypropyl beta-CD, methyl beta-CD and gamma-CD, have been studied in pH 12 aqueous solutions at 25 A degrees C and in the solid state. Different phase solubility profiles of TB in the presence of CDs have been obtained: A(L) type for TB with hydroxypropyl beta-CD and gamma-CD, A(P) type for the complexes with methyl beta-CD and alpha-CD, while a B(S) profile was found for TB-beta-CD. The apparent stability constants of the complexes were calculated at 25 A degrees C from the phase solubility diagrams. The higher increase of TB solubility, up to 200-fold, together with the higher value of the stability constant were found for the complex with methyl beta-CD. Solid systems of 1:1 drug:CD molar ratio were prepared and characterised using X-ray diffraction patterns, thermal analysis and FTIR spectroscopy. The coevaporation method can be considered the best method in preparing these solid complexes. The complexes of TB with natural CDs, except with alpha-CD, were crystalline, whereas the methyl and hydroxypropyl derivatives gave rise to amorphous phases. Dissolution rate studies have been performed with TB-beta-CD and TB-HP beta-CD complexes, showing a positive influence of complexation on the drug dissolution.