Colloids and Surfaces B: Biointerfaces 112 (2013) 9–15 Contents lists available at ScienceDirect Colloids and Surfaces B: Biointerfaces jou rn al hom epage: www.elsevier.com/locate/colsurfb An integrated buccal delivery system combining chitosan ﬁlms impregnated with peptide loaded PEG-b-PLA nanoparticles Concetta Giovino, Isaac Ayensu, John Tetteh, Joshua S. Boateng ∗ Department of Pharmaceutical, Chemical and Environmental Sciences, Faculty of Engineering and Science, University of Greenwich at Medway, Chatham Maritime, Kent ME4 4TB, UK a r t i c l e i n f o Article history: Received 30 April 2013 Received in revised form 28 June 2013 Accepted 5 July 2013 Available online xxx Keywords: Buccal mucosa delivery Chitosan ﬁlms EpiOral TM Insulin Nanoparticles Peptide delivery a b s t r a c t Peptide (insulin) loaded nanoparticles (NPs) have been embedded into buccal chitosan ﬁlms (Ch-ﬁlms- NPs). These ﬁlms were produced by solvent casting and involved incorporating in chitosan gel (1.25% w/v), NPs-Insulin suspensions at three different concentrations (1, 3, and 5 mg of NPs per ﬁlm) using glycerol as plasticiser. Film swelling and mucoadhesion were investigated using 0.01 M PBS at 37 ◦ C and tex- ture analyzer, respectively. Formulations containing 3 mg of NPs per ﬁlm produced optimised ﬁlms with excellent mucoadhesion and swelling properties. Dynamic laser scattering measurements showed that the erosion of the chitosan backbone controlled the release of NPs from the ﬁlms, preceding in vitro drug (insulin) release from Ch-ﬁlms-NPs after 6 h. Modulated release was observed with 70% of encapsulated insulin released after 360 h. The use of chitosan ﬁlms yielded a 1.8-fold enhancement of ex vivo insulin permeation via EpiOral TM buccal tissue construct relative to the pure drug. Flux and apparent permeation coefﬁcient of 0.1 g/cm 2 /h and 4 × 10 -2 cm 2 /h were respectively obtained for insulin released from Ch- ﬁlms-NPs-3. Circular dichroism and FTIR spectroscopy demonstrated that the conformational structure of the model peptide drug (insulin) released from Ch-ﬁlms-NPs was preserved during the formulation process. © 2013 Elsevier B.V. All rights reserved. 1. Introduction There has been signiﬁcant interest in mucoadhesive buccal for- mulations including ﬁlms in recent years. The interest in ﬁlm based formulations is driven not only by the promise of improved patient compliance [1,2], but also by the possibility to deliver various ther- apeutic drug classes such as peptides and vaccines as an alternative to currently used parenteral administration. Buccal ﬁlms avoid ﬁrst pass effect by exploiting absorption through the venous system that drains from the cheek area [3]. For example, Donnelly et al. [18] and Singh et al. [6] formulated buccal ﬁlms to release drug locally in order to treat oral candidiasis. Similarly, ﬁlms containing drugs, meant for systemic activity, such as insulin, octreotide and leuprolide [4,5], have been reported in the literature. However, drug bioavailability through the buccal mucosa, especially for peptides, is quite low (i.e. 0.1–5.0%) due to the relatively large molecular size, Abbreviations: ATR-FTIR, attenuated total reﬂectance-Fourier transform infra- red; CD, circular dichroism; DLS, dynamic laser scattering; NP, nanoparticle; PBS, phosphate buffered saline; PEG, polyethylene glycol; PEG-b-PLA, poly(ethylene glycol)methyl ether-block-polylactide; PVA, polyvinylalcohol; PVP, polyvinyl pyrrolidone; TFA, triﬂuoroacetic acid; TH, trehalose. ∗ Corresponding author. Tel.: +44 0208 331 8980. E-mail addresses: j.s.boateng@gre.ac.uk, joshboat@hotmail.com (J.S. Boateng). presence of both physical (mucous layer that lines a multi-layered epithelium) and chemical (presence of peptidases and proteolytic enzymes) barriers [4,5]. In the light of these challenges, numerous approaches have been investigated for improving drug permeability [6]. One of such approaches is the formulation of nanoparticles (NPs) incorporated into carrier vehicles such as mucoadhesive buccal ﬁlms [7]. NPs can improve the stability of active substances [8] and be compati- ble with tissue and cells when synthesised from biocompatible and biodegradable materials [9]. Moreover, NPs show promise as active vectors due to their capacity to encapsulate and release drugs [10]. In addition, their sub-cellular size allows relatively higher uptake compared to other particulate systems [11,12]. Cui and co-workers demonstrated that ﬁlms containing NPs exhibited higher mucoad- hesion than blank ﬁlms [13]. This higher mucoadhesion effect was attributed to the high number of carboxyl groups of NPs which increased the chances of hydrogen bonding with the buccal mucosa. In this paper, we investigated chitosan based ﬁlms as drug deliv- ery systems. The ﬁlms were loaded with NPs containing insulin. NPs were manufactured using PEG-b-PLA copolymer, which were loaded with different amounts of insulin. The ﬁlms were char- acterised for mucoadhesiveness, swelling and physico-chemical properties. The dissolution studies were conducted to understand the release of peptide drug (insulin) from chitosan ﬁlms loaded with NPs. Furthermore, EpiOral TM buccal tissue construct was used as an 0927-7765/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.colsurfb.2013.07.019