Improved Local Anesthesia at Inflamed Tissue Using the Association of Articaine and Copaiba Oil in Avocado Butter Nanostructured Lipid Carriers.

Unsuccessful anesthesia often occurs under an inflammatory tissue environment, making dentistry treatment extremely painful and challenging. Articaine (ATC) is a local anesthetic used at high (4%) concentrations. Since nanopharmaceutical formulations may improve the pharmacokinetics and pharmacodynamics of drugs, we encapsulated ATC in nanostructured lipid carriers (NLCs) aiming to increase the anesthetic effect on the inflamed tissue. Moreover, the lipid nanoparticles were prepared with natural lipids (copaiba (Copaifera langsdorffii) oil and avocado (Persia gratissima) butter) that added functional activity to the nanosystem. NLC-CO-A particles (~217 nm) showed an amorphous lipid core structure according to DSC and XDR. In an inflammatory pain model induced by λ-carrageenan in rats, NLC-CO-A improved (30%) the anesthetic efficacy and prolonged anesthesia (3 h) in relation to free ATC. In a PGE2-induced pain model, the natural lipid formulation significantly reduced (~20%) the mechanical pain when compared to synthetic lipid NLC. Opioid receptors were involved in the detected analgesia effect since their blockage resulted in pain restoration. The pharmacokinetic evaluation of the inflamed tissue showed that NLC-CO-A decreased tissue ATC elimination rate (ke) by half and doubled ATC's half-life. These results present NLC-CO-A as an innovative system to break the impasse of anesthesia failure in inflamed tissue by preventing ATC accelerated systemic removal by the inflammatory process and improving anesthesia by its association with copaiba oil.

DoE development of ionic gradient liposomes: A successful approach to improve encapsulation, prolong anesthesia and decrease the toxicity of etidocaine.

Etidocaine (EDC) is a long-acting local anesthetic of the aminoamide family whose use was discontinued in 2008 for alleged toxicity issues. Ionic gradient liposomes (IGL) are nanostructured carriers for which an inner/outer gradient of ions increases drug upload. This work describes IGLEDC, a formulation optimized by Design of Experiments, composed of hydrogenated soy phosphatidylcholine:cholesterol:EDC, and characterized by DLS, NTA, TEM/Cryo-TEM, DSC and 1H NMR. The optimized IGL showed significant encapsulation efficiency (41 %), good shelf stability (180 days) and evidence of EDC interaction with the lipid bilayer (as seen by DSC and 1H NMR results) that confirms its membrane permeation. In vitro (release kinetics and cytotoxicity) tests showed that the encapsulation of EDC into the IGL promoted sustained release for 24 h and decreased by 50 % the intrinsic toxicity of EDC to Schwann cells. In vivo IGLEDC decreased the toxicity of EDC to Caenorhabditis elegans by 25 % and extended its anesthetic effect by one hour, after infiltrative administration, at clinically used (0.5 %) concentration, in rats. Thus, this novel drug delivery system is a promise for the possible reintroduction of EDC in clinics, aiming at the control of operative and postoperative pain.

Docetaxel Loaded in Copaiba Oil-Nanostructured Lipid Carriers as a Promising DDS for Breast Cancer Treatment.

Breast cancer is the neoplasia of highest incidence in women worldwide. Docetaxel (DTX), a taxoid used to treat breast cancer, is a BCS-class-IV compound (low oral bioavailability, solubility and intestinal permeability). Nanotechnological strategies can improve chemotherapy effectiveness by promoting sustained release and reducing systemic toxicity. Nanostructured lipid carriers (NLC) encapsulate hydrophobic drugs in their blend-of-lipids matrix, and imperfections prevent drug expulsion during storage. This work describes the preparation, by design of experiments (23 factorial design) of a novel NLC formulation containing copaiba oil (CO) as a functional excipient. The optimized formulation (NLCDTX) showed approximately 100% DTX encapsulation efficiency and was characterized by different techniques (DLS, NTA, TEM/FE-SEM, DSC and XRD) and was stable for 12 months of storage, at 25 °C. Incorporation into the NLC prolonged drug release for 54 h, compared to commercial DTX (10 h). In vitro cytotoxicity tests revealed the antiproliferative effect of CO and NLCDTX, by reducing the cell viability of breast cancer (4T1/MCF-7) and healthy (NIH-3T3) cells more than commercial DTX. NLCDTX thus emerges as a promising drug delivery system of remarkable anticancer effect, (strengthened by CO) and sustained release that, in clinics, may decrease systemic toxicity at lower DTX doses.

Hybrid Nanobeads for Oral Indomethacin Delivery.

The oral administration of the anti-inflammatory indomethacin (INDO) causes severe gastrointestinal side effects, which are intensified in chronic inflammatory conditions when a continuous treatment is mandatory. The development of hybrid delivery systems associates the benefits of different (nano) carriers in a single system, designed to improve the efficacy and/or minimize the toxicity of drugs. This work describes the preparation of hybrid nanobeads composed of nanostructured lipid carriers (NLC) loading INDO (2%; w/v) and chitosan, coated by xanthan. NLC formulations were monitored in a long-term stability study (25 °C). After one year, they showed suitable physicochemical properties (size < 250 nm, polydispersity < 0.2, zeta potential of −30 mV and spherical morphology) and an INDO encapsulation efficiency of 99%. The hybrid (lipid-biopolymers) nanobeads exhibited excellent compatibility between the biomaterials, as revealed by structural and thermodynamic properties, monodisperse size distribution, desirable in vitro water uptake and prolonged in vitro INDO release (26 h). The in vivo safety of hybrid nanobeads was confirmed by the chicken embryo (CE) toxicity test, considering the embryos viability, weights of CE and annexes and changes in the biochemical markers. The results point out a safe gastro-resistant pharmaceutical form for further efficacy assays.

Antineoplastics Encapsulated in Nanostructured Lipid Carriers.

Ideally, antineoplastic treatment aims to selectively eradicate cancer cells without causing systemic toxicity. A great number of antineoplastic agents (AAs) are available nowadays, with well-defined therapeutic protocols. The poor bioavailability, non-selective action, high systemic toxicity, and lack of effectiveness of most AAs have stimulated the search for novel chemotherapy protocols, including technological approaches that provide drug delivery systems (DDS) for gold standard medicines. Nanostructured lipid carriers (NLC) are DDS that contain a core of solid and lipid liquids stabilised by surfactants. NLC have high upload capacity for lipophilic drugs, such as the majority of AAs. These nanoparticles can be prepared with a diversity of biocompatible (synthetic or natural) lipid blends, administered by different routes and functionalised for targeting purposes. This review focused on the research carried out from 2000 to now, regarding NLC formulations for AAs (antimetabolites, antimitotics, alkylating agents, and antibiotics) encapsulation, with special emphasis on studies carried out in vivo. NLC systems for codelivery of AAs were also considered, as well as those for non-classical drugs and therapies (natural products and photosensitisers). NLC have emerged as powerful DDS to improve the bioavailability, targeting and efficacy of antineoplastics, while decreasing their toxic effect in the treatment of different types of cancer.

Prolonged anesthesia and decreased toxicity of enantiomeric-excess bupivacaine loaded in ionic gradient liposomes.

Bupivacaine is the most employed local anesthetic in surgical procedures, worldwide. Its systemic toxicity has directed the synthesis of the less toxic, S(-) enantiomer. This work describes a formulation of ionic gradient liposomes (IGL) containing S75BVC, an enantiomeric excess mixture of 75% S(-) and 25% R(+) bupivacaine. IGL prepared with 250 mM (NH4)2SO4 in the inner aqueous core of phosphatidylcholine and cholesterol (3:2 mol%) vesicles plus 0.5% S75BVC showed average sizes of 312.5 ± 4.5 nm, low polydispersity (PDI < 0.18), negative zeta potentials (-14.2 ± 0.2 mV) and were stable for 360 days. The encapsulation efficiency achieved with IGLS75BVC (%EE = 38.6%) was higher than with IGL prepared with racemic bupivacaine (IGLRBVC, %EE = 28.3%). TEM images revealed spherical vesicles and µDSC analysis provided evidence on the interaction of the anesthetic with the lipid bilayer. Then, in vitro - release kinetics and cytotoxicity- and in vivo - toxic effects in Zebrafish and biochemical/histopathological analysis plus analgesia in Wistar rats - tests were performed. IGLS75BVC exhibited negligible toxicity against Schwann cells and Zebrafish larvae, and it did not affect biochemical markers or the morphology of rat tissues (heart, brain, cerebellum, sciatic nerve). The in vitro release of S75BVC from IGL was extended from 4 to 24 h, justifying the prolonged anesthetic effect measured in rats (~9 h). The advantages of IGLS75BVC formulation over IGLRBVC and plain bupivacaine formulations (prolonged anesthesia, preferential sensorial blockade, and no toxicity) confirm its potential for clinical use in surgical anesthesia.

Rational design of polymer-lipid nanoparticles for docetaxel delivery.

In this work, a stable nanocarrier for the anti-cancer drug docetaxel was rational designed. The nanocarrier was developed based on the solid lipid nanoparticle preparation process aiming to minimize the total amount of excipients used in the final formulations. A particular interest was put on the effects of the polymers in the final composition. In this direction, two poloxoamers -Pluronic F127 and F68- were selected. Some poloxamers are well known to be inhibitors of the P-glycoprotein efflux pump. Additionally, their poly-ethylene-oxide blocks can help them to escape the immune system, making the poloxamers appealing to be present in a nanoparticle designed for the treatment of cancer. Within this context, a factorial experiment design was used to achieve the most suitable formulations, and also to identify the effects of each component on the final (optimized) systems. Two final formulations were chosen with sizes < 250 nm and PDI < 0.2. Then, using dynamic light scattering and nanotracking techniques, the stability of the formulations was assessed during six months. Structural studies were carried on trough different techniques: DSC, x-ray diffraction, FTIR-AR and Molecular Dynamics. The encapsulation efficiency of the anticancer drug docetaxel (> 90%) and its release dynamics from formulations were measured, showing that the polymer-lipid nanoparticle is suitable as a drug delivery system for the treatment of cancer.

Nanohybrid hydrogels designed for transbuccal anesthesia.

BACKGROUND: Local anesthesia in dentistry is by far the most terrifying procedure for patients, causing treatment interruption. None of the commercially available topical formulations is effective in eliminating the pain and phobia associated to the needle insertion and injection. MATERIALS AND METHODS: In this work we prepared a nanostructured lipid-biopolymer hydrogel for the sustained delivery of lidocaine-prilocaine (LDC-PLC) for transbuccal pre-anesthesia. The lipid was composed of optimized nanostructured lipid carriers (NLC) loaded with 5% LDC-PLC (NLC/LDC-PLC). The biopolymer counterpart was selected among alginate, xanthan (XAN), and chitosan matrices. The XAN-NLC hydrogel presented the most uniform aspect and pseudoplastic rheological profile, as required for topical use; therefore, it was selected for subsequent analyses. Accelerated stability tests under critical conditions (40°C; 75% relative humidity) were conducted for 6 months, in terms of drug content (mg/g), weight loss (%), and pH. RESULTS: In vitro LDC-PLC release profile through Franz diffusion cells revealed a bimodal kinetics with a burst effect followed by the sustained release of both anesthetics, for 24 hours. Structural analyses (fourier transform infrared spectroscopy, differential scanning calorimetry and scanning electron microscopy) gave details on the molecular organization of the hybrid hydrogel, confirming the synergic interaction between the components. Safety and efficacy were evaluated through in vitro cell viability (3T3, HaCat, and VERO cells) and in vivo antinociceptive (tail-flick, in mice) tests, respectively. In comparison to a control hydrogel and the eutectic mixture of 5% LDC-PLC cream (EMLA®), the XAN-NLC/LDC-PLC hybrid hydrogel doubled and quadrupled the anesthetic effect (8 hours), respectively. CONCLUSION: Considering such exciting results, this multifaceted nanohybrid system is now ready to be further tested in clinical trials.

Sustained Release from Ionic-Gradient Liposomes Significantly Decreases ETIDOCAINE Cytotoxicity.

PURPOSE: Etidocaine (EDC) is a long lasting local anesthetic, which alleged toxicity has restricted its clinical use. Liposomes can prolong the analgesia time and reduce the toxicity of local anesthetics. Ionic gradient liposomes (IGL) have been proposed to increase the upload and prolong the drug release, from liposomes. METHODS: First, a HPLC method for EDC quantification was validated. Then, large unilamellar vesicles composed of hydrogenated soy phosphatidylcholine:cholesterol with 250 mM (NH4)2SO4 - inside gradient - were prepared for the encapsulation of 0.5% EDC. Dynamic light scattering, nanotracking analysis, transmission electron microscopy and electron paramagnetic resonance were used to characterize: nanoparticles size, polydispersity, zeta potential, concentration, morphology and membrane fluidity. Release kinetics and in vitro cytotoxicity tests were also performed. RESULTS: IGLEDC showed average diameters of 172.3 ± 2.6 nm, low PDI (0.12 ± 0.01), mean particle concentration of 6.3 ± 0.5 × 1012/mL and negative zeta values (-10.2 ± 0.4 mV); parameters that remain stable during storage at 4°C. The formulation, with 40% encapsulation efficiency, induced the sustained release of EDC (ca. 24 h), while reducing its toxicity to human fibroblasts. CONCLUSION: A novel formulation is proposed for etidocaine that promotes sustained release and reduces its cytotoxicity. IGLEDC can come to be a tool to reintroduce etidocaine in clinical use.