Uso de xantana e ciclodextrina como sistema de liberação controlada de cloreto de cetilpiridínio

Abstract

New formulations of controlled release systems (SLCs) have reached the market demonstrating progress in this field. SLCs can be defined as technologies designed to achieve greater drug efficiency and reduced adverse effects. From this perspective, the present study tested cetylpyridinium chloride (CCP), a cationic surfactant, with broad-spectrum antimicrobial activity against bacteria, including Staphylococcus aureus and Streptococcus mutans. At the appropriate concentration, CCP is widely used as an antiseptic, due to its low toxicity and non-irritation of mucous membranes. CCP was combined with xanthan (XANT) and modified cyclodextrins, hydroxypropyl-β-cyclodextine (HPβCD) and poly-β-cyclodextrin (pCD), in order to develop controlled release systems for this compound, since XANT presents ability to spontaneously associate with cationic compounds and cyclodextrins (CDs) ability to incorporate guest molecules. The samples were characterized in the solid state by Fourier transform infrared spectroscopy (FTIR) and thermal analyzes (TGA and DTA). The interactions between CCP, CDs and XANT were characterized in solution, by dynamic light scattering (DLS), conductivity and zeta potential (ZP) measurements. The interaction of CCP with XANT was also investigated by stationary rheology at 25 oC. To understand the thermodynamic complexation parameters, the interactions between the compounds were characterized by isothermal titration calorimetry. The antimicrobial action of the respective complexes formed by CCP with HPβCD (CCP/HPβCD), with pCD (CCP/pCD) and with XANT (CCP/XANT) was evaluated through biological studies against four strains of Staphylococcus aureus and one strain of Streptococcus mutans. The results obtained demonstrated spontaneous formation of CCP inclusion complexes in modified βCDs and the CCP complex with XANT. Regarding biological activity, it was observed that in the presence of HPβCD and pCD there was a reduction in MIC and LD50 compared to S. aureus strains, suggesting that the complexes showed promise for use in controlled CCP release systems. S. mutans inhibition/adhesion assays showed that the CCP/XANT complex was the one that showed the greatest inhibition of biofilm formation.