Pullulan-based nanoparticles as carriers for transmucosal protein delivery

Abstract

Polymeric nanoparticles have revealed very effective in transmucosal delivery of proteins. Polysaccharides are among the most used materials for the production of these carriers, owing to their structural flexibility and propensity to evidence biocompatibility and biodegradability. In parallel, there is a preference for the use of mild methods for their production, in order to prevent protein degradation, ensure lower costs and easier procedures that enable scaling up.In this work we propose the production of pullulan-based nanoparticles by a mild method of polyelectrolyte complexation. As pullulan is a neutral polysaccharide, sulfated and aminated derivatives of the polymer were synthesized to provide pullulan with a charge. These derivatives were then complexed with chitosan and carrageenan, respectively, to produce the nanocarriers. Positively charged nanoparticles of 180-270 nm were obtained, evidencing ability to associate bovine serum albumin, which was selected as model protein. In PBS pH 7.4, pullulan-based nanoparticles were found to have a burst release of 30% of the protein, which maintained up to 24h. Nanoparticle size and zeta potential were preserved upon freeze-drying in the presence of appropriate cryoprotectants. A factorial design was approached to assess the cytotoxicity of raw materials and nanoparticles by the metabolic test MTT. Nanoparticles demonstrated to not cause overt toxicity in a respiratory cell model (Calu-3). Pullulan has, thus, demonstrated to hold potential for the production of nanoparticles with an application in protein delivery.

Pullulan-based nanoparticles: future therapeutic applications in transmucosal protein delivery

“…These nanoparticles exhibited great ability for the association of proteins with distinct properties (insulin and bovine serum albumin, MW of 5.7 and 67 kDa, respectively) and were proposed for nasal and pulmonary transmucosal delivery. Having demonstrated a clear non-cytotoxic behavior in model respiratory cell lines (Calu-3 and A549) [17], the nanoparticles also revealed to not induce an inflammatory response upon contact with the same cell lines The ana lysis of all the data available in the literature suggests the adequacy of the biomaterial pullulan for drug-delivery strategies. Particularly, although counting on a reduced number of works, pullulan-based nano particles reveal potential regarding transmucosal protein delivery.…”

“…In this regard, apart from the demonstrated role of pullulan on the adhesion of A. pullulans to biological surfaces, such as leaves [9], cell adhesion to pullulan-based surfaces was reported on a number of occasions [10][11][12]. Pullulan-based nanoparticles were actually reported to adhere to the nasal epithelium in a study regarding nasal vaccination [13], and the authors' group has also verified the adherence of pullulan nanoparticles to respiratory epithelial cells (Calu-3 and A549), although to a limited extent [ Pullulan has been increasingly described as matrix-forming material of drug and gene nanocarriers [5,7,[13][14][15][16][17]. The most common characteristic of these carriers is the use of hydrophobic derivatives of pullulan, namely cholesteryl-pullulan, because this provides an amphiphilic polymer with the capacity to form nanoparticles by self-aggregation.…”

“…Nevertheless, although the potential application in protein delivery was mentioned frequently, the demonstration of results in the area has been scarce. The delivery of insulin, bovine serum albumin, DNA and IL-12 was effectively proposed [4,[15][16][17][18]. The authors' group has recently given a contribution to the field.…”

Recent Developments in Application of Polymeric Nanoparticles as Drug Carriers

“…On the other hand, poly(ethylene glycol) (PEG) [15] and Eudragits ® [10,31] belong to the group of nonbiodegradable synthetic polymeric materials. The -biodegradable natural polymers already used for the preparation of nanoparticulate DDSs include poly(L-glutamic acid) (PGA) produced by Bacillus subtilis [37], pullulan produced from starch by the fungus Aureobasidium pullulans [33], gelatin [6], alginate [9,33], chitosan [15] and its derivatives including N-palmitoyl chitosan [14] or mannosemodified trimethyl chitosan-cysteine (MTC) conjugate [20] and many others [19]. Intriguingly, the widespread application of PLGA results from its relatively inert composition, stable rate of degradation and known degradation products [22], namely lactic acid and glycolic acid [23].…”

“…It deserves to be emphasized that several polymers are characterized by satisfying biocompatibility and predictable biodegradability [9,22] while others are non-degradable or undergo slow degradation [22,32]. Remarkably, polymer-based nanoparticles can be administered orally [20,23], intravenously [18], percutaneously [30], ophthalmically [27], pulmonarily [12,25], transmucosally to nose and lungs [33] or delivered to the brain via inner ear administration [16]. It is noteworthy that selected polymers are approved by the Food and Drug Administration (FDA) to be used for therapeutic applications [27].…”