Utilização de nanofribras de celulose de biomassas residuais das indústrias do papel e fumageira como adjuvante na preparação de granulados contendo teofilina

Abstract

Cellulose nanofibers (CNFs) derived from tobacco and paper chips may have different applications including polymer composites, fabrics, cosmetics and medicines. Considering this wide applicability and emphasizing, above all, the application of this biomass in medicines development, the evaluation of nicotine presence and toxic wastes are important. In this study, the CNFs were obtained by mechanical fibrillation by varying the cellulose concentration (0.5 and 2.0%, w/v), obtaining suspensions, in which only tobacco’s stalk suspensions were treated by mercerization. After that, the suspensions of both biomass were dried by different methods (freeze-drying, spray- rying and oven-drying) for characterization. CNFs were denominated as paper chips cellulose nanofibers at 0.5 and 2.0 % (CAP_05 and CAP_2) and tobacco stalk cellulose nanofibers at 0.5 and 2.0 % (NFCT_05 and NFCT_2). CNFs were characterized by thin layer chromatography (TLC), proton nuclear magnetic resonance (1H NMR), morphological analysis, -cellulose determination, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermal analysis. CNFs obtained from both biomass and polyvinylpyrrolidone (PVP) were used as binders and theophylline granules were prepared by wet granulation nd evaluated for friability, compressive strength, porosity and surface area, particle size distribution, drug content and dissolution profile. The results demonstrate the absence of nicotine in tobacco stalk. The grinding process was efficient in the production of CNFs and freeze-drying was the most appropriate drying method to obtain the average diameters of CAP_05 of 67.0 ± 2 nm and CAP_2 of 40.0 ± 2 nm. For NFCT_05 and NFCT_2 the mean diameter obtained was 32.8 ± 0.3 nm and 34.3 ± 6.2 nm, respectively. The concentration of cellulose nanofibers influences the obtained fibrils diameter, because the higher the concentration, the smaller the diameter. NFCT_05 thermal stability increased and crystallinity decreased with alkali treatment in the tobacco stalk sample. The characterization techniques used allowed to evaluate the tobacco stalk and to increase its use. The use of CNFs proved to be feasible as binder in the granules preparation containing theophylline. The granules prepared with paper chips nanofibers had more fines than granulates prepared with tobacco stalk nanofibers as a binder. The granules containing the tobacco stalk nanofibers presented good to excellent flow properties and the highest compaction force was obtained for the granules GNFCT_05 + PVP (3.79 ± 0.17 kg) and GNFCT_2 + PVP (3.51 ± 0,06 kg). The morphological analysis showed the presence of porosities in granulates, confirmed by the porosity and surface area assay. The dissolution assay showed that granules prepared with CNFs as binder exhibited a behavior similar to that of PVP on theophylline release. [resumo fornecido pelo autor]