Colloids and Surfaces B: Biointerfaces 111 (2013) 609–617 Contents lists available at SciVerse ScienceDirect Colloids and Surfaces B: Biointerfaces jou rn al hom epage: www.elsevier.com/locate/colsurfb Close-packed vesicles for diclofenac skin delivery and fibroblast targeting Maria Letizia Manca a , Maria Manconi a , Angela Maria Falchi b , Ines Castangia a , Donatella Valenti a , Sandrina Lampis c , Anna Maria Fadda a,∗ a Dept. Scienze della Vita e dell’Ambiente, University of Cagliari, Cagliari 09124, Italy b Dept. di Scienze Biomediche, Cittadella Universitaria di Monserrato, Cagliari, Italy c Dept. di Chimica, Cittadella Universitaria di Monserrato, Cagliari, Italy a r t i c l e i n f o Article history: Received 9 March 2013 Received in revised form 14 May 2013 Accepted 3 July 2013 Available online 12 July 2013 Keywords: Phospholipid vesicles Skin delivery Penetration enhancer Cell toxicity 3T3 uptake a b s t r a c t Concentrated and interconnected penetration enhancer containing vesicles (PEVs) are proposed as car- riers for dermal delivery of diclofenac. PEVs were prepared by using a commercial phosphatidylcholine mixture (180 mg/m) and transcutol in different amounts. Conventional liposomes were also prepared and tested as control. All vesicles showed a mean size ranging from 75 to 253 nm with fairly narrow size distribution, negative zeta potential value, and drug loading capacity between 48 and 70%. SWAXS studies showed that composition affected vesicle structure and morphology: 10 and 30% transcutol PEVs were unilamellar while liposomes and 20% transcutol PEVs were multilamellar. Rheological studies demon- strated that control liposomes and 10 and 30% transcutol containing PEVs behaved as Newtonian fluids while 20% transcutol containing PEVs showed a plastic behavior. Ex vivo (trans)dermal delivery exper- iments showed an improved skin deposition of diclofenac when PEVs were used. Vesicle toxicity and uptake of fibroblasts, target of inflammation treatment, were evaluated by MTT test and fluorescence microscopy. Control liposomes and PEVs were both able to interact and being internalized by the 3T3 fibroblasts at all time exposure tested. Furthermore, PEVs showed to be able to reduce the in vitro drug toxicity. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Topical delivery of drugs has several advantages over other traditional routes of administration, including improved bioavail- ability for drugs that suffer gastrointestinal environment and/or hepatic first effects. However, the barrier nature of the stratum corneum (SC) represents a significant obstacle for most drugs to be delivered into and through the skin using the classical dosage forms such as creams, ointments, and gels. To overcome the bar- rier properties of the SC and enhance drug transport across intact skin, several techniques have been developed [1–3]. One of the approaches especially studied in the last decades is the use of lipid nanocarriers, such as innovative liposomal vesicles [4–6]. Introduction of these delivery systems in nanomedicine has sev- eral advantages that include safety of the carrier, its capability to enhance drug delivery into/through the skin as well as to deliver the drug to its therapeutic target while reducing drug ∗ Corresponding author at: Via Ospedale 72, 09124 Cagliari, Italy. Tel.: +39 0706758565; fax: +39 0706758710. E-mail address: mfadda@unica.it (A.M. Fadda). toxicity. Diclofenac (DCF), a phenyl acetic acid derivative, is a potent member of the non-steroidal anti-inflammatory drugs (NSAIDs), frequently used for treatment of rheumatic disorders and other chronic inflammatory diseases. In chronic inflammations, such as arthritis, fibroblasts are the source of anti-inflammatory media- tors and contribute to disease persistence in a defined anatomical location. Fibroblasts show a disordered behavior that causes an excessive survival and accumulation of leukocytes within inflamed tissues [7]. They are responsible for tissue injury and cartilage inva- sion in the presence of inflammatory infiltrates. Therefore, topical DCF delivery could be useful to reduce the drug systemic toxic- ity while improving its local efficacy [8]. The use of vesicular drug delivery systems, such as liposomes, niosomes, ethosomes, and transfersomes, may enhance DCF delivery into and through the skin allowing the drug to reach therapeutic levels into inflamed fibroblasts [9–13]. In previous works, we prepared and tested pen- etration enhancer-containing vesicles (PEVs) as promising carriers for enhanced (trans)dermal delivery of diclofenac, in the form of either acid or sodium salt [14,15]. In the present work, we propose concentrated and close-packed PEVs prepared using a high con- centration (180 mg/ml) of a commercial lipid mixture containing phosphatidylcholine, phosphatidylethanolamine, fatty acids and 0927-7765/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.colsurfb.2013.07.014