Squalenyl Hydrogen Sulfate Nanoparticles for Simultaneous Delivery of Tobramycin and an Alkylquinolone Quorum Sensing Inhibitor Enable the Eradication of P.†aeruginosa Biofilm Infections.

Elimination of pulmonary Pseudomonas aeruginosa (PA) infections is challenging to accomplish with antibiotic therapies, mainly due to resistance mechanisms. Quorum sensing inhibitors (QSIs) interfering with biofilm formation can thus complement antibiotics. For simultaneous and improved delivery of both active agents to the infection sites, self-assembling nanoparticles of a newly synthesized squalenyl hydrogen sulfate (SqNPs) were prepared. These nanocarriers allowed for remarkably high loading capacities of hydrophilic antibiotic tobramycin (Tob) and a novel lipophilic QSI at 30 % and circa 10 %, respectively. The drug-loaded SqNPs showed improved biofilm penetration and enhanced efficacy in relevant biological barriers (mucin/human tracheal mucus, biofilm), leading to complete eradication of PA biofilms at circa 16-fold lower Tob concentration than Tob alone. This study offers a viable therapy optimization and invigorates the research and development of QSIs for clinical use.

Exploring the potential of tianeptine matrix tablets: Synthesis, physico-chemical characterization and acute toxicity studies.

The main objective of the present study was to explore the potential of matrix tablets as extended release dosage form of tianeptine, using HMPC K100 as a polymer. HPMC K100 extended the release of the drug from formulation due to the gel-like structure. Direct compression method was adopted to compress the tablets using different concentrations of polymer. Tablets were evaluated for pre-compression and post-compression parameters. Drug release study showed that tablet extends the release of drug with the increasing concentration of polymer. Drug, polymers and tablets were analyzed and/or characterized for compatibility, degradation, thermal stability, amorphous or crystalline nature via FTIR, DSC, TGA, XRD studies. SEM study predicted that tablets had a uniform structure. HPMC K100 based tablets were similar to that of the reference product. Acute toxicity study conducted on Swiss albino mice showed that matrix tablets were safe and non-toxic, as no changes in physical activity and functions of organs were observed. Biochemical and histopathological study revealed lack of any kind of abnormality in liver and renal function. Moreover, necrotic changes were absent at organ level.

Liposomal Cytarabine Induces Less Neurocognitive Dysfunction Than Intrathecal Methotrexate in an Animal Model.

Liposomal cytarabine is currently being tested clinically as an alternative to intrathecal (IT) methotrexate (MTX) for preventing relapse within the central nervous system among patients with acute lymphoblastic leukemia. To compare the toxicity and cognitive deficits caused by IT MTX versus liposomal cytarabine, juvenile Long Evans rats were treated with IT injections of MTX 1 mg/kg×4 doses over 8 days, or liposomal cytarabine 0.8 mg once. Mean concentrations of free cytarabine in cerebrospinal fluid remained above the cytotoxic threshold of 0.4 µM for 2 weeks after dosing. Animals treated with liposomal cytarabine exhibited normal recognition and spatial memory 4 weeks after injection. In contrast, exposure to IT MTX led to impaired cognitive function. In addition, mean hematocrit on day 11 was significantly lower in the MTX-treated animals (30.8%; 95% confidence interval, 27.0%-34.7%; n=6) compared with that in the liposomal cytarabine-treated animals (39.5%; 95% confidence interval, 38.4%-40.6%; n=6; P<0.0001). Our data suggest that liposomal cytarabine induces fewer neurocognitive deficits and less acute hematologic toxicity compared with IT MTX. Liposomal cytarabine may therefore have therapeutic advantages over IT MTX, if it is equally effective in preventing relapse.

The Use of an Efficient Microfluidic Mixing System for Generating Stabilized Polymeric Nanoparticles for Controlled Drug Release.

Microfluidics is a promising system for efficiently optimizing the experimental conditions for preparing nanomedicines, such as self-assembled nanoparticles. Poly(lactic-co-glycolic acid) (PLGA) nanoparticles are promising drug carriers allowing sustained drug release. Here, we encapsulated the model drug curcumin, which has many pharmacological activities, into PLGA nanoparticles and investigated the effects of experimental conditions on the resulting PLGA nanoparticles using a microfluidics system with a staggered herringbone structure that can stir solutions through chaotic advection. The total flow rate and flow rate ratio of the solutions in the microfluidics system affected the diameters, polydispersity index, and encapsulation efficiency of the resulting PLGA nanoparticles and produced small, homogenous PLGA nanoparticles. The incorporation of polyethylene glycol (PEG)-PLGA into the PLGA nanoparticles reduced the particle size and improved the encapsulation efficiency. Initial burst release from the PLGA nanoparticles was prevented by the incorporation of PEG2000-PLGA. Curcumin-loaded PEGylated PLGA nanoparticles showed cytotoxicity similar to that of other formulations. This microfluidics system allows high throughput and is scalable for the efficient preparation of PLGA nanoparticles and PEGylated PLGA nanoparticles. Our results will be useful for developing novel PLGA-based polymer nanoparticles by using the microfluidics.

New Dendrimer-Based Nanoparticles Enhance Curcumin Solubility.

Curcumin, the main curcuminoid of the popular Indian spice turmeric, is a potent chemopreventive agent and useful in many different diseases. A major limitation of applicability of curcumin as a health promoting and medicinal agent is its extremely low bioavailability due to efficient first pass metabolism, poor gastrointestinal absorption, rapid elimination, and poor aqueous solubility. In the present study, nanotechnology was selected as a choice approach to enhance the bioavailability of the curcuminis. A new polyamidoamine dendrimer (G0.5) was synthesized, characterized, and tested for cytotoxicity in human breast cancer cells (MCF-7). No cytotoxicity of G0.5 was found in the range between 10-3 and 3 × 10-8 M. Consequently, G0.5 was used to prepare spherical nanoparticles of ca. 150 nm, which were loaded with curcumin [molar ratio G0.5/curcumin 1 : 1 (formulation 1) and 1 : 0.5 (formulation 2)]. Remarkably, the occurrence of a single population of nanoparticles having an excellent polydispersity index (< 0.20) was found in both formulations. Formulation 1 was selected to test in vitro drug release because it was superior in terms of encapsulation efficiency (62 %) and loading capacity (32 %). The solubility of curcumin was increased ca. 415 and 150 times with respect to the unformulated drug, respectively, for formulation 1 and formulation 2. The release of curcumin from the nanoparticles showed an interesting prolonged and sustained release profile.

Physicochemical and biological characterization of sustained isopropyl unoprostone-release device made of poly(ethyleneglycol) dimethacrylates.

Transscleral drug delivery is becoming increasingly popular to manage posterior eye diseases. To evaluate the clinical application of a transscleral, sustained, unoprostone (UNO)-release device (URD) constructed of photopolymerized tri(ethyleneglycol) dimethacrylate and poly(ethyleneglycol) dimethacrylate, we evaluated physicochemical and biological properties of this device. The URD consists of a drug-impermeable reservoir and a semi-permeable cover. The in vitro release rate of UNO from the URD increased with increasing temperatures from 20 to 45 °C. Scanning electron microscopy and atomic-force microscopy showed that the border between the reservoir and drug formulation was sharply defined but that between the cover and drug was poorly determined, indicating that UNO could permeate only through the cover. For stability tests, the URDs were sterilized with ethylene oxide gas and stored at 40 °C/75% for 3 and 6 months and at 25 °C/60% for 3, 6, 9, 12, 18, and 24 months; UNO content and release rate at 37 °C were then evaluated. There was no significant decrease in either UNO content or release rate after the storage conditions. Cytotoxicity was evaluated by examining the colony formation of Chinese hamster fibroblast V79 cells in a media extract of the URD without UNO. This extract did not affect colony formation of V79 cells, indicating the cytocompatibility of the URD. In conclusion, the URD was physically stable for 24 months and is potentially useful for clinical application.

The development of non-toxic ionic-crosslinked chitosan-based microspheres as carriers for the controlled release of silk sericin.

Silk sericin is recently shown to possess various biological activities for biomedical applications. While various sericin carriers were developed for drug delivery system, very few researches considered sericin as a bioactive molecule itself. In this study, sericin incorporated in the chitosan-based microspheres was introduced as a bioactive molecule and bioactive carrier at the same time. The chitosan/sericin (CH/SS) microspheres at different composition (80/20, 70/30, 60/40, and 50/50) were successfully fabricated using anhydroustri-polyphosphate (TPP) as a polyanionic crosslinker. The microspheres with an average size of 1-4 µm and narrow size distribution were obtained. From FT-IR spectra, the presence of both chitosan and sericin in the microspheres confirmed the occurrence of ionic interaction that crosslink them within the microspheres. We also found that the CH/SS microspheres prepared at 50/50 could encapsulate sericin at the highest percentage (37.28%) and release sericin in the most sustained behavior, possibly due to the strong ionic interaction of the positively charged chitosan and the negatively charged sericin. On the other hand, the composition of CH/SS had no effect on the degradation rate of microspheres. All microspheres continuously degraded and remained around 20% after 14 days of enzymatic degradation. This explained that the ionic crosslinkings between chitosan and sericin could be demolished by the enzyme and hydrolysis. Furthermore, we have verified that all CH/SS microspheres at any concentrations showed non-toxicity to L929 mouse fibroblast cells. Therefore, we suggested that the non-toxic ionic-crosslinked CH/SS microspheres could be incorporated in wound dressing material to achieve the sustained release of sericin for accelerated wound healing.

Screening for an ivermectin slow-release formulation suitable for malaria vector control.

BACKGROUND: The prospect of eliminating malaria is challenged by emerging insecticide resistance and vectors with outdoor and/or crepuscular activity. Ivermectin can simultaneously tackle these issues by killing mosquitoes feeding on treated animals and humans. A single oral dose, however, confers only short-lived mosquitocidal plasma levels. METHODS: Three different slow-release formulations of ivermectin were screened for their capacity to sustain mosquito-killing levels of ivermectin for months. Thirty rabbits received a dose of one, two or three silicone implants containing different proportions of ivermectin, deoxycholate and sucrose. Animals were checked for toxicity and ivermectin was quantified periodically in blood. Potential impact of corresponding long-lasting formulation was mathematically modelled. RESULTS: All combinations of formulation and dose released ivermectin for more than 12 weeks; four combinations sustained plasma levels capable of killing 50% of Anopheles gambiae feeding on a treated subject for up to 24 weeks. No major adverse effects attributable to the drug were found. Modelling predicts a 98% reduction in infectious vector density by using an ivermectin formulation with a 12-week duration. CONCLUSIONS: These results indicate that relatively stable mosquitocidal plasma levels of ivermectin can be safely sustained in rabbits for up to six months using a silicone-based subcutaneous formulation. Modifying the formulation of ivermectin promises to be a suitable strategy for malaria vector control.

Cytotoxicity Evaluation of pH-Controlled Antitumor Drug Release System of Titanium Dioxide Nanotubes.

Application of nanotechnology and nanomaterials in cancer therapeutics has attracted much attention in recent years. Nano titanium dioxide is one of the most important inorganic functional materials. Cellular toxicity of pH-controlled antitumor drug release system of titanium dioxide nanotubes (TiO2-NTs) in pancreatic cancer cells (SW1990) was evaluated in this paper. The anticancer drug, doxorubicin (DOX) was easily loaded on TiO2-NTs through adsorption forces because of its high specific surface area and perfect surface activity. The drug release from the nanotubes was pH dependent. The toxicological effects were studied after co-incubation of SW1990 with TiO2-NTs-DOX, TiO2-NTs and DOX, respectively. The cellular effect of DOX released from the TiO2-NTs-DOX was same as when DOX was used alone, indicating that the synthesized TiO2-NTs are well qualified as drug carriers in antitumor drug controlled-release system.

Photo-crosslinkable biopolymers targeting stem cell adhesion and proliferation: the case study of gelatin and starch-based IPNs.

The present work focuses on the development of biomaterials that support the adhesion and the proliferation of adipose-tissue derived stem cells. Therefore, gelatin and starch are selected as starting materials. Both hydrogel building blocks are of great interest as they provide a general chemical structure comparable to the protein and the polysaccharide constituting part of the extracellular matrix. Crosslinkable side groups are incorporated on both biopolymers to enable the subsequent chemical crosslinking, thereby ensuring their stability at physiological temperature. An in vitro cellular assay revealed that the hydrogels developed are biocompatible and supported cell adhesion of adipose-tissue derived mesenchymal stem cells. The presence of the starch phase tempered the adhesion resulting in local cell detachment. The results thus indicate that by carefully varying the ratio of the two building blocks, hydrogels can be developed possessing a controllable cell adhesion behavior.

Microparticulated systems based on chitosan and poly(vinyl alcohol) with potential ophthalmic applications.

Spherical microparticles for encapsulation of drugs for the treatment of diseases, with a diameter ranging between 2 and 4 µm, were obtained by double crosslinking (ionic and covalent) of chitosan and poly(vinyl alcohol) blend in a water-in-oil emulsion. Microparticles characterisation was carried out in terms of structural, morphological and swelling properties in aqueous media. The presence of chitosan in particles composition confers them a pH-sensitive character. Toxicity and hemocompatibility tests prove the biocompatible character of microparticles. The pilocarpine loading capacity is high as well as the release efficiency which increases up to 72 and 82% after 6 h. The obtained results recommend the microparticles as sustained release drug carriers for the treatment of eye diseases.

Drug-eluting beads loaded with antiangiogenic agents for chemoembolization: in vitro sunitinib loading and release and in vivo pharmacokinetics in an animal model.

PURPOSE: The combination of embolic beads with a multitargeted tyrosine kinase inhibitor that inhibits tumor vessel growth is suggested as an alternative and improvement to the current standard doxorubicin-eluting beads for use in transarterial chemoembolization. This study demonstrates the in vitro loading and release kinetics of sunitinib using commercially available embolization microspheres and evaluates the in vitro biologic efficacy on cell cultures and the resulting in vivo pharmacokinetics profiles in an animal model. MATERIALS AND METHODS: DC Bead microspheres, 70-150 µm and 100-300 µm (Biocompatibles Ltd., Farnham, United Kingdom), were loaded by immersion in sunitinib solution. Drug release was measured in saline in a USP-approved flow-through apparatus and quantified by spectrophotometry. Activity after release was confirmed in cell culture. For pharmacokinetics and in vivo toxicity evaluation, New Zealand white rabbits received sunitinib either by intraarterial injection of 100-300 µm sized beads or per os. Plasma and liver tissue drug concentrations were assessed by liquid chromatography-tandem mass spectroscopy. RESULTS: Sunitinib loading on beads was close to complete and homogeneous. A total release of 80% in saline was measured, with similar fast-release profiles for both sphere sizes. After embolization, drug plasma levels remained below the therapeutic threshold (< 50 ng/mL), but high concentrations at 6 hours (14.9 µg/g) and 24 hours (3.4 µg/g) were found in the liver tissue. CONCLUSIONS: DC Bead microspheres of two sizes were efficiently loaded with sunitinib and displayed a fast and almost complete release in saline. High liver drug concentrations and low systemic levels indicated the potential of sunitinib-eluting beads for use in embolization.

Ecotoxicological evaluation of poly(epsilon-caprolactone) nanocapsules containing triazine herbicides.

The triazine class of herbicides includes the compounds ametryn, atrazine, and simazine, which are used to control weeds in plantations of crops such as maize, sorghum, and sugar cane. Despite their acceptance in agriculture, these herbicides can be dangerous to the environment, depending on their toxicity, the degree of contamination, and the duration of exposure. Controlled release systems are increasingly used to mitigate problems of toxicity and minimize environmental impacts, and can also increase herbicide efficiency. The objective of this work was to prepare poly(epsilon-caprolactone) nanocapsules containing ametryn and atrazine, and evaluate their toxicity to aquatic organisms as well as in cytogenetic tests employing human lymphocyte cultures. The PCL nanocapsules were prepared according to the interfacial deposition of pre-formed polymer method. Ecotoxicological assays were performed with the alga Pseudokirchneriella subcapitata and the microcrustacean Daphnia similis. The cytogenetic tests consisted of observing mitotic index alterations after exposing lymphocyte cell cultures to different formulations. Encapsulation of the herbicides in the nanocapsules resulted in lower toxicity to the alga and higher toxicity to the microcrustacean, compared to the herbicides alone. The cytogenetic tests showed that formulations of nanocapsules containing the herbicides were less toxic than the herbicides alone. The findings indicate the potential of the nanocapsule formulations in agricultural applications, where they could help to reduce the quantities of herbicides used as well as impacts on the environment and human health.

In vitro sustained release study of gallic acid coated with magnetite-PEG and magnetite-PVA for drug delivery system.

The efficacy of two nanocarriers polyethylene glycol and polyvinyl alcohol magnetic nanoparticles coated with gallic acid (GA) was accomplished via X-ray diffraction, infrared spectroscopy, magnetic measurements, thermal analysis, and TEM. X-ray diffraction and TEM results showed that Fe3O4 nanoparticles were pure iron oxide having spherical shape with the average diameter of 9 nm, compared with 31 nm and 35 nm after coating with polyethylene glycol-GA (FPEGG) and polyvinyl alcohol-GA (FPVAG), respectively. Thermogravimetric analyses proved that after coating the thermal stability was markedly enhanced. Magnetic measurements and Fourier transform infrared (FTIR) revealed that superparamagnetic iron oxide nanoparticles could be successfully coated with two polymers (PEG and PVA) and gallic acid as an active drug. Release behavior of gallic acid from two nanocomposites showed that FPEGG and FPVAG nanocomposites were found to be sustained and governed by pseudo-second-order kinetics. Anticancer activity of the two nanocomposites shows that the FPEGG demonstrated higher anticancer effect on the breast cancer cell lines in almost all concentrations tested compared to FPVAG.

Development of drug delivery systems based on layered hydroxides for nanomedicine.

Layered hydroxides (LHs) have recently fascinated researchers due to their wide application in various fields. These inorganic nanoparticles, with excellent features as nanocarriers in drug delivery systems, have the potential to play an important role in healthcare. Owing to their outstanding ion-exchange capacity, many organic pharmaceutical drugs have been intercalated into the interlayer galleries of LHs and, consequently, novel nanodrugs or smart drugs may revolutionize in the treatment of diseases. Layered hydroxides, as green nanoreservoirs with sustained drug release and cell targeting properties hold great promise of improving health and prolonging life.

Influence of the type of vegetable oil on the drug release profile from lipid-core nanocapsules and in vivo genotoxicity study.

The use of rice bran (RB), soybean (SB) or sunflower seed (SF) oils to prepare lipid-core nanocapsules (LNCs) as controlled drug delivery systems was investigated. LNCs were prepared by interfacial deposition using the preformed polymer method. All formulations showed negative zeta potential and adequate nanotechnological characteristics (particle size 220-230 nm, polydispersity index < 0.20). The environmental safety was evaluated through an in vivo protocol (Allium cepa test) and LNCs containing RB, SB or SF oils did not present genotoxic potential. Clobetasol propionate (CP) was selected as a model drug to evaluate the influence of the type of vegetable oil on the control of the drug release from LNCs. Biphasic drug release profiles were observed for all formulations. After 168 h, the concentration of drug released from the formulation containing SF oil was lower (0.36 mg/mL) than from formulations containing SB (0.40 mg/mL) or RB oil (0.45 mg/mL). Good correlations between the consistency indices for the LNC cores and the burst and sustained drug release rate constants were obtained. Therefore, the type of the vegetal oil was shown as an important factor governing the control of drug release from LNCs.

In situ forming hydrogels via catalyst-free and bioorthogonal "tetrazole-alkene" photo-click chemistry.

In situ forming hydrogels were developed from 4-arm poly(ethylene glycol)-methacrylate (PEG-4-MA) and -tetrazole (PEG-4-Tet) derivatives through catalyst-free and bioorthogonal "tetrazole-alkene" photo-click chemistry. PEG-4-MA and PEG-4-Tet (Mn = 10 kg/mol) were soluble at 37 °C in phosphate buffer (PB, pH 7.4, 10 mM) at total polymer concentrations ranging from 20 to 60 wt % but formed fluorescent hydrogels upon 365 nm UV irradiation at an intensity of 20.6, 30.7, or 60 mW/cm(2). The gelation times ranged from ca. 50 s to 5 min, and storage moduli varied from 0.65 to 25.2 kPa depending on polymer concentrations and degrees of Tet substitution in PEG-4-Tet conjugates. The cell experiments via an indirect contact assay demonstrated that these "tetrazole-alkene" photo-click PEG hydrogels were noncytotoxic. The high specificity of photo-click reaction renders thus obtained PEG hydrogels particularly interesting for controlled protein release. Notably, in vitro release studies showed that cytochrome c (CC), γ-globulins (Ig), and recombinant human interleukin-2 (rhIL-2) all were released from PEG hydrogels in a sustained and quantitative manner over a period of 14-20 days. Importantly, released CC and rhIL-2 exhibited comparable biological activities to native CC and rhIL-2, respectively. These results confirm that "tetrazole-alkene" photo-click reaction is highly compatible with these loaded proteins. This photo-controlled, specific, efficient, and catalyst-free click chemistry provides a new and versatile strategy to in situ forming hydrogels that hold tremendous potentials for protein delivery and tissue engineering.

Agarose hydrogels embedded with pH-responsive diblock copolymer micelles for triggered release of substances.

Hybrid agarose hydrogels embedded with pH-responsive diblock copolymers micelles were developed to achieve functional hydrogels capable of stimulus-triggered drug release. Specifically, a well-defined poly(ethylene oxide) (PEO)-based diblock copolymer, PEO-b-poly(2-(N,N-diisopropylamino)ethyl methacrylate) (PEO(113)-b-PDPAEMA(31), where the subscripts represent the degrees of polymerization of two blocks), was synthesized by atom transfer radical polymerization. PDPAEMA is a pH-responsive polymer with a pKa value of 6.3. The PEO(113)-b-PDPAEMA(31) micelles were formed by a solvent-switching method, and their pH-dependent dissociation behavior was investigated by dynamic light scattering and fluorescence spectroscopy. Both studies indicated that the micelles were completely disassembled at pH = 6.40. The biocompatibility of PEO(113)-b-PDPAEMA(31) micelles was demonstrated by in vitro primary cortical neural culture. Hybrid agarose hydrogels were made by cooling 1.0 wt % agarose solutions that contained various amounts of PEO(113)-b-PDPAEMA(31) micelles at either 2 or 4 °C. Rheological measurements showed that the mechanical properties of gels were not significantly adversely affected by the incorporation of diblock copolymer micelles with a concentration as high as 5.0 mg/g. Using Nile Red as a model hydrophobic drug, its incorporation into the core of diblock copolymer micelles was demonstrated. Characterized by fluorescent spectroscopy, the release of Nile Red from the hybrid hydrogel was shown to be controllable by pH due to the responsiveness of the block copolymer micelles. Based on the prominent use of agarose gels as scaffolds for cell transplantation for neural repair, the hybrid hydrogels embedded with stimuli-responsive block copolymer micelles could allow the controlled delivery of hydrophobic neuroprotective agents to improve survival of transplanted cells in tune with signals from the surrounding pathological environment.

Evaluation of poly (1, 6-bis-(p-carboxyphenoxy) hexane-co-sebacic acid microspheres for controlled basal insulin delivery.

PURPOSE: To develop poly 1,3-bis-(p-carboxyphenoxy) hexane-co-sebacic acid (p(CPH/SA)) microspheres for controlled basal insulin delivery and evaluate their in vivo efficacy and toxicity. METHODS: A series of CPH/SA copolymers with molar ratios 20/80, 40/60, and 50/50 were synthesized and characterized. The stability of encapsulated insulin and the fraction of insulin released from microspheres were assessed by different analytical techniques. The skin from the injection site of rats was examined microscopically for histomorphological changes. RESULTS: Increasing the molar ratio of CPH/SA significantly (p < 0.05) improved insulin loading and controlled insulin release. However, dimer aggregates of insulin were observed as CPH/SA molar ratio increased. Co-encapsulation of zinc oxide with insulin inhibited dimer aggregate formation and further controlled insulin release. Insulin was stable after entrapment into microspheres and during in vitro release studies. Administration of microsphere formulations CPH/SA 40/60 and 50/50 with zinc oxide controlled insulin release and maintained basal insulin levels for 42 days in rats. Skin sections showed minimal inflammation with no evidence for histomorphological changes and toxicity. CONCLUSIONS: Insulin-loaded CPH/SA microspheres demonstrated considerable potential as controlled delivery system for insulin. Copolymer microspheres maintained basal insulin levels for 42 days and were biodegradable and biocompatible.

Solid lipid nanoparticles with and without hydroxypropyl-ß-cyclodextrin: a comparative study of nanoparticles designed for colonic drug delivery.

New solid lipid nanoparticles (SLN), composed of Compritol ATO888 (C) and hydroxypropyl-ß-cyclodextrin (HP), were developed in order to study a new colon-specific formulation for diclofenac sodium (D) delivery. The prepared batches differ from each other by the molecular ratio between HP and D and by the composition of the matrix. Nanoparticles composed of an exclusively lipid matrix and nanoparticles with an oligomeric and lipid matrix were compared in order to establish the effect of both components on the drug delivery tests performed. The SLN preparation method was based on the oil/water hot homogenization process. Emulsions produced were cooled at room temperature and lyophilized in order to obtain dried nanoparticles; possible damage to nanoparticle shape and size was avoided by the addition of cryoprotectants to the aqueous dispersion of nanoparticles before exsiccation. An in vitro toxicity study was performed using CaCo(2) cells to establish the safety of the prepared SLN. Data obtained showed that production method studied guarantees emulsions composed of nanosized drops which can be dried by lyophilization into SLN with a size range of 300-600 nm. In vitro and ex vivo tests demonstrated that dried SLN can be considered as colon delivery systems; however, the matrix composition as well as the presence of cryoprotectant on their surface influences the release and permeation rate of D. The in vitro toxicity studies indicated that the SLN are well tolerated.