Spray-Dried Cellulose Nanofibers as Novel Tablet Excipient

Abstract

Abstract. The purpose of this study was to evaluate the potential of cellulose nanofibers (also referred as microfibrillated cellulose, nanocellulose, nanofibrillated, or nanofibrillar cellulose) as novel tabletting material. For this purpose, physical and mechanical properties of spray-dried cellulose nanofibers (CNF) were examined, and results were compared to those of two commercial grades of microcrystalline cellulose (MCC), Avicel PH101 and Avicel PH102, which are the most commonly and widely used direct compression excipients. Chemically, MCC and CNF are almost identical, but their physical characteristics, like mechanical properties and surface-to-volume ratio, differ remarkably. The novel material was characterized with respect to bulk and tapped as well as true density, moisture content, and flow properties. Tablets made of CNF powder and its mixtures with MCC with or without paracetamol as model compound were produced by direct compression and after wet granulation. The tensile strength of the tablets made in a series of applied pressures was determined, and yield pressure values were calculated from the measurements. With CNF, both wet granulation and direct compression were successful. During tablet compression, CNF particles were less prone to permanent deformation and had less pronounced ductile characteristics. Disintegration and dissolution studies showed slightly faster drug release from direct compression tablets with CNF, while wet granulated systems did not have any significant difference.

Caracterização de nanofilmes de celulose nanofibrilada obtida em diferentes consistências

“…Como pode ser observado na Figura 1 a celulose nanofibrilada obtida após 20 passes pelo moinho desfibrilador apresentou aspecto de gel para os três tratamentos considerados. Conforme também relatado por outros autores, métodos mecânicos de fibrilação da celulose para obtenção de celulose nanofibrilada a partir de fibras vegetais levam a formação de um gel com elevado teor de água, neste trabalho variando de 98,5 a 99,5% (BESBES et al, 2011;KOLAKOVIC et al, 2011). A diferença verificada em relação à fluidez do gel deve-se justamente as diferentes porcentagens de celulose presentes em cada um dos tratamentos, sendo menor no tratamento 0,5% (Figura 1A) e maior em 1,5% (Figura 1C).…”

“…A celulose nanofibrilada consiste em um material obtido pela desintegração da celulose submetida a um processo mecânico de homogeneização, no qual é degradada, promovendo a exposição e abertura das superfícies anteriormente situadas no interior das fibras, as fibrilas e as microfibrilas (TURBAK et al, 1983citados por ANDRESEN et al, 2006GARDNER et al, 2008;KOLAKOVIC et al, 2011). Este processo ocasiona um aumento da superfície externa, possibilitando uma maior área de contato e maior capacidade de gerar fortes ligações de hidrogênio entre as microfibrilas da parede celular, produzindo um material com alta resistência.…”

Nano-Crystalline Cellulose as a Novel Tablet Excipient for Improving Solubility and Dissolution of Meloxicam

“…The fibrils and fibril aggregates are quite often denoted cellulose nanofibers (NCC) or microfibrils (Herrick et al, 1983;Turbak et al, 1983;Chakraborty et al, 2005;Svagan et al, 2007;Quievy et al, 2010). Recently, separation of cellulose nanofibers from macroscopic cellulose fibers has become the subject of much attention due to their characteristics such as high surface-to-volume ratio and outstanding mechanical properties (Kolakovic et al, 2011). There is still considerable continuing research into the use of MCC and other types of cellulose in advanced drug delivery systems whereby the rate of the drug release may be controlled by microparticle inclusion, .…”

“…excipient layering or tablet coating (Khan and Zhu, 1999;Watanabe et al, 2002;El-Maradny, 2007;Gomez-Carracedo et al, 2007;Podczeck et al, 2008;Baumann et al, 2009;Bley et al, 2009;Javadzadeh et al, 2009;Knight et al, 2009;Kranz et al, 2009;Jackson, Letchford et al, 2011). Traditional method of production of MCC that includes strongly acidic conditions leads to extensive hydrolysis of amorphous fractions and formation of short rod-like MCC fibril bundles with low aspect ratio (Kolakovic, Peltonen et al, 2011). Method of production of NCC that was reported for the first time by Turbak et al (Turbak et al, 1983) required high-energy input.…”

“…However, new methods using super grinder treatment or high-pressure refiner (Chakraborty et al, 2005;Yano et al, 2005), microfluidizer (Zimmermann et al, 2004), and high-pressure homogenizer treatment (Herrick et al, 1983;Dufresne et al, 1997;Nakagaito and Yano, 2005) have been proposed. All these methods led to a production of gel-like water suspension with high water content, which can be further processed into powder by spray drying (Kolakovic et al, 2011) or freeze drying (Emara et al, 2014). NCC is at the moment a subject of continuing research.…”