engleski

Lipid/alginate nanoparticles for dexamethasone nasal delivery

INTRODUCTION Nasal administration of medicines with local effect is the natural choice for the treatment of acute and chronic topical nasal disorders. Accordingly, topical nasal steroid sprays are the mainstream treatment for patients with nasal polyps. High-dose topical nasal steroids have shown promising results with less systemic effects than oral steroids. However, long-term use of high topically applied doses could be related to adverse effects such as changes in serum cortisol and/or intraocular pressure (1). In this work, we present the development of dexamethasone- loaded lipid/alginate nanoparti- cles that could provide prolonged dexamethasone release and prolonged residence time at the nasal mucosa, ensuring its local effect upon the administration of a lower dose. Prolonged residence time can be expected due to alginate bioadhesive properties, but could further be improved by adjusting alginate concentration in the nanoparticle suspension to the range in which it could form hydrogel in contact with calcium ions present in the nasal mucosa (2, 3). MATERIALS AND METHODS Materials Sodium alginate was purchased from NovaMatrix®, Norway. Lecithin S100 was obtained from Lipoid, Germany. Dimethyldioctadecylammonum bromide (DDAB) was purchased from Sigma-Aldrich, Germany. Dexamethasone (Dex) was obtained from Sanofi Aventis, France. All other reagents were of analytical grade. Methods Dex-loaded lipid/alginate nanoparticles were obtained by injection of ethanolic lipid/Dex so-lution into aqueous alginate solution (200 g/ml ; Table 1). The non-entrapped Dex was sepa-rated by filtration through 0.4-μm membrane filters (Millipore®, Switzerland). Dex content in the nanoparticles was determined by UPLC (Agilent Infinity 1290 Agilent, Santa Clara, CA, USA). Particle size and zeta potential was determined by photon correlation spectroscopy (Zetasizer 3000 HS, Malvern Instruments). In vitro drug release was studied by dialysis against water containing SDS (0.03%, w/w) as the release medium in order to ensure sink conditions (Spectra/Por® 4 Dialysis Tubing, MWCO 12–14 kDa, Medicell International Ltd., UK) (4). Biocompatibility of nanoparticles was assessed using Caco-2 cells (American Type Culture Collection, USA). Cell viability was determined with the colorimetric MTT (3-[4, 5- dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide, Sigma) assay. Tab. 1: The composition of solutions used for the preparation of Dex- loaded lipid/alginate nanoparticles. Lecithin (mg) DDAB (mg) Dex (mg) Alginate (mg) DN1 50 0.7 10 5 DN2 50 1 10 5 DN3 50 3 10 5 DN4 50 5 10 5 Ethanolic solution (2 ml) Aqueous solution (23 mL) RESULTS AND DISCUSSION The size and zeta-potential of lipid/alginate nanoparticles depended on the content of cationic lipid DDAB (Table 2). Increase in DDAB content led to stronger interaction with alginate, re-sulting in nanoparticle size and negative surface charge increase. The obtained value of zeta- potential near -30 mV is beneficial concerning the physical stability of nanoparticle suspensions prepared. The highest Dex entrapment efficiency (63.8 %) was obtained for nanoparticles prepared with the highest DDAB content (DN4), resulting in Dex content in nanoparticle suspension of 255  7 g/ml. Tab. 2: The main characteristics of Dex-loaded lipid/alginate nanoparticles. Dex content (µg/ml) Size (nm) PDI Zeta-potential (mV) DN1 (N1) 218 ± 3 109.1 ± 3.1 (129.7 ± 1.2) 0.540 (0.531) -14.2 ± 0.3 (-16.0 ± 0.4) DN2 (N2) 207 ± 1 129.1 ± 2.5 (134.9 ± 4.4) 0.514 (0.610) -21.9 ± 0.5 (-19.5 ± 0.3) DN3 (N3) 204 ± 7 258.6 ± 4.2 (278.9 ± 1.4) 0.343 (0.519) -26.5 ± 0.3 (-24.9 ± 0.6) DN4 (N4) 255 ± 7 252.3 ± 2.4 (276.6 ± 4.6) 0.241 (0.374) -31.7 ± 1.0 (-30.6 ± 1.0) Values are mean  SD (n = 3) ; values in brackets refer to Dex-free nanoparticles ; PDI, polydispersity index All lipid/alginate nanoparticles were characterised by prolonged Dex release and a signifi-cantly lower release rate (Fig. 1) than that observed for Dex solution (t50% 1 h). Fig. 1: Release profiles of Dex from lipid/alginate nanoparticles in water containing SDS (0.03, w/w, %). The profile of Dex diffusion from the SDS aqueous solution (0.003%, w/v) across the dialysis membrane is also presented. Data are expressed as the mean ± SD (n = 3). This particularly refers to DN4 nanoparticles having t50% of approximately 3 h. Although the Caco-2 cell line has an intestinal origin, it has already been used to study more general membrane effects of drug delivery systems intended for nasal administration (5). In biocompatibility study, the concentration of nanoparticles was expressed as the concentration of lecithin in the system, and ranged from 50-400 g/ml. Cell viability assay showed no toxic effects of nanoparticles at the tested concentration range and the 2-h exposure. CONCLUSIONS This study demonstrates the potential of lipid/alginate nanoparticle suspension to act as a Dex delivery platform characterized by prolonged release and sufficient charge to ensure suspen- sion physical stability. This is a prerequisite for the suspension successful formulation into an in situ gelling nasal system that would ensure prolonged residence at the nasal mucosa. ACKNOWLEDGEMENTS This work was supported by a project entitled “Development of in vitro models for early biopharmaceutical characterization, ” which was funded by the University of Zagreb. REFERENCES 1. Martino BJ, Church CA, Seiberling KA, Effect of intranasal dexamethasone on endogenous cortisol level and intraocular pressure, Int. Forum Allergy Rhinol., 2015 ; 5: 605-609. 2. Kaklamani G, Cheneler D, Grover LM, Adams MJ, Bowen J, Mechanical properties of alginate hydrogels manufactured using external gelation, J. Mech. Behav. Biomed. Mater., 2014 ; 36: 135-142. 3. Josef E, Zilberman M, Bianco-Peled H, Composite alginate hydrogels: An innovative approach for the controlled release of hydrophobic drugs, Acta Biomater., 2010 ; 6: 4642-4649. 4. Pepić I, Hafner A, Lovrić J, Pirkić B, Filipović- Grčić J, A nonionic surfactant/chitosan micelle system in an innovative eye drop formulation, J. Pharm. Sci., 2010 ; 99: 4317-4325. 5. Hafner A, Lovrić J, Voinovich D., Filipović-Grčić J, Melatonin-loaded lecithin/chitosan nanoparticles: physicochemical characterisation and permeability through Caco-2 cell monolayers, Int. J. Pharm., 2009 ; 381: 205- 213.

nanoparticles ; nasal polyps ; dexamethasone ; alginate ; Caco-2

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