Estudo da população de Malassezia pachydermatis em otite externa canina e avaliação da sensibilidade in vitro e in vivo frente a antifúngicos.

Otite externa é uma enfermidade comumente observada em cães encaminhados a clínica veterinária e a etiologia desta doença varia em função de diversas combinações entre os fatores predisponentes, primários e perpetuantes responsáveis pela enfermidade. Este trabalho teve como objetivo pesquisar a presença da Malassezia pachydermatis em otite externa canina e avaliar a suscetibilidade in vivo e in vitro da levedura frente ao cetoconazol e tiabendazol. Para isto foi pesquisada a presença da levedura M. pachydermatis em otite externa de 168 cães encaminhados aos Hospitais de Clínicas Veterinárias da Universidade Federal do Rio Grande do Sul e da Universidade Federal de Pelotas, assim como em clínicas e canis particulares. Após identificação morfológica e bioquímica da levedura, foi realizada extração de DNA pelo método de fenol-clorofórmio de amostras selecionadas para análise pela técnica de RAPD- PCR, para verificação de heterogeneidade molecular. Foi realizada a reprodução experimental de malasseziose ótica em 14 cães inoculados com a levedura para posterior tratamento. Dois grupos de 30 cães com malasseziose ótica foram selecionados para tratamento com os produtos comerciais otológicos contendo tiabendazol e cetoconazol (Otodem plus® e Aurivet® respectivamente). Com os isolados de M. pachydermatis obtidos desses animais tratados foi realizado antifungigrama através da técnica de Microdoluição em Caldo (MC) para o tiabendazol e técnica do ETEST para o cetoconazol. Os resultados deste último foram comparados com a técnica de MC. A M. pachydermatis foi isolada em 139 (82,7%) casos de otite externa, sendo que molecularmente, a levedura apresentou diferenças, recebendo nove subdivisões a partir do primer utilizado. Os animais inoculados com a levedura desenvolveram a otite externa e o tratamento realizado com os produtos comerciais Aurivet® e Otodem plus® foi eficaz. Dos 60 animais tratados para malasseziose, 86,7% apresentaram cura clínica. A CIM do tiabendazol através da técnica de MC variou de 0,03 a >4mg/ml, com média de 3,67mg/ml. A CIM do cetoconazol, através do ETEST, variou de 0,004 a 0,75mg/ml, com média de 0,156mg/ml. A CIM do cetoconazol, através do método MC variou de 0,0009375 a 0,06mg/ml, com CIM média de 0,00815mg/ml. Através do cálculo de CIM50 e CIM90, observou-se frente ao tiabendazol, resistência em 13,7% dos isolados, sensibilidade intermediária em 47,1% e 39,2% isolados foram sensíveis. Quanto ao cetoconazol, através da técnica do ETEST, a resistência foi observada em 11,1% dos isolados, sensibilidade intermediária foi encontrada em 41,7% e 47,2% isolados foram sensíveis. Pela MC, foi observada resistência em 15,4% isolados, sensibilidade intermediária em 35,9% isolados e 48,7% foram sensíveis. As médias das CIMs observadas entre os 17 isolados testados simultaneamente frente ao cetoconazol com as duas metodologias, ETEST e MC, foi 0,103mg/ml e 0,0119mg/ml respectivamente. Nesta comparação podemos observar a concordância de resultados em apenas seis amostras (35,3%), quatro sensíveis e duas, sensibilidade intermediária. As combinações terapêuticas testadas nos animais foram eficazes no tratamento da malasseziose ótica canina, porém não houve relação entre resultado do teste in vitro e a resposta in vivo dos antifúngicos frente a levedura.

Modelo in vitro de parkinsonismo experimental induzido por rotenona: investigação de mecanismos de ação, neuroproteção e morte celular

Evidências crescentes na literatura têm sugerido papel importante para os fatores ambientais, como a exposição a pesticidas, na patogênese da doença de Parkinson. Em animais experimentais, a exposição à rotenona, um pesticida e piscicida de uso comum, induz características de parkinsonismo através da inibição do complexo I mitocondrial. O objetivo deste estudo foi investigar a morte de neurônios induzida por rotenona utilizando culturas primárias mistas neurônio/glia derivadas de hipocampo e de mesencéfalo ventral de ratos, bem como o papel do Ca2+ na neste modelo experimental e a utilização de extrato aquoso de folhas de mogno com substâncias com alto poder antioxidante. A perda neuronal foi analisada com ensaios colorimétricos (MTT e LDH). Nossos resultados mostraram significativa redução na viabilidade celular após exposição à rotenona de maneira dependente de concentração, mas não dependente de tempo. Foi observada igual e elevada suscetibilidade em culturas mistas neurônio/glia derivadas de hipocampo e de mesencéfalo ventral ao agente neurotóxico. Em termos mecanicísticos, nossos resultados mostraram um papel discreto desempenhado pelo Ca2+ mitocondrial na neurodegeneração induzida por rotenona. Além disso, neste paradigma utilizado, verificamos que o extrato aquoso de folhas de mogno não promoveu proteção contra a toxicidade da rotenona, na concentração testada; ainda, promoveu efeito sinérgico em associação com rotenona. Verificou-se ainda que a rotenona, bem como o extrato de mogno promoveu indução de morte celular tanto por necrose quanto por apoptose, nas concentrações utilizadas. Os resultados deste estudo devem avançar nosso conhecimento sobre o mecanismo de ação de fatores ambientais na patogênese da doença de Parkinson.

Leishmania (L.) amazonensis inibe a maturação e a função ativadora das células de Langerhans da pele tratadas com TNF-α e anti-CD40 in vitro

Leishmania amazonensis é um dos principais agentes etiológicos em um amplo espectro de formas clínicas da Leishmaniose Tegumentar Americana. De modo geral, a resistência frente às leishmanioses decorre do desenvolvimento de uma resposta imune celular eficiente, porém muitos estudos têm demonstrado que citocinas específicas ou combinações de citocinas podem ser fatores de resistência ou suscetibilidade à infecção por L. amazonensis. Estudos recentes sugerem a participação das células de Langerhans (LCs) nas resposta anti-Leishmania, porém os mecanismos envolvidos durante esta interação são ainda pouco estudados. Objetivos: Estudar o papel do TNF-α e anti-CD40 nas interações in vitro entre as LCs e L. amazonensis, observando o perfil de citocinas produzidas e a expressão de moléculas de superfície, bem como verificar a capacidade destas células em ativar a produção de IFN-γ e IL-4 por células do linfonodo. Metodologia: As LCs foram isoladas da epiderme de camundongos BALB/c e incubadas com promastigotas de L. amazonensis, TNF-α e/ou anti- CD40. Após 24h, as LCs foram co-cultivadas com células obtidas de linfonodos por 72h. As citocinas IL-6, IL-12, IFN-γ e IL-4 foram dosadas por ensaio imunoenzimático (ELISA) e as moléculas de superfície foram analisadas por citometria de fluxo. Resultados: Os níveis de IL- 6 e IL-12p70 produzidos pela LCs foram significativamente reduzidos após interação com L. amazonensis, mesmo após o tratamento das LCs com TNF-α ou anti-CD40. Em relação às moléculas de superfície, não houve diferença na expressão de CD207 em nenhum dos grupos, porém a presença de L. amazonensis promoveu uma redução significativa na expressão de CD40 nas LCs tratadas com TNF-α ou anti-CD40, e aumentou a expressão de CD86 em todos os grupos. Na presença de L. amazonensis, as células do linfonodo apresentaram uma produção diminuída de IFN-γ e não houve alteração na produção de IL-4. Quando cocultivadas com LCs estimuladas previamente com L. amazonensis, a produção de IFN-γ também foi reduzida, mesmo na presença dos estímulos TNF-α e/ou anti-CD40. Não foram observadas alterações significativas na produção de IL-4 pelas células do linfonodo cocultivadas nas mesmas condições experimentais. Conclusão: L. (L.) amazonensis exerce um efeito imunomodulador sobre a resposta imune mediada por LCs, inibindo a produção de IL-6 e IL-12p70 e expressão de CD40, além de impedir a ativação da produção de IFN-γ por células do linfonodo co-cultivadas com LCs, mesmo após tratamento com TNF-α e anticorpo anti-CD40.

Estudo da atividade antibacteriana in vitro de ativos desodorantes em solução hidroalcoólica

As estruturas da derme como os folículos pilosos e os ductos das glândulas sudoríparas e de óleo, proporcionam uma via de passagem por onde os micro-organismos atingem os tecidos mais profundos da pele. A transpiração fornece umidade e alguns nutrientes para o crescimento microbiano (TORTORA, 2012). Dentre os vários gêneros de bactérias que constituem a microbiota residente das axilas, encontram-se o Staphylococcus e o Micrococcus, responsáveis pelo odor do ácido isovalérico, o odor caracterísitico das axilas. Estão presentes também bactérias do gênero Corynebacterium, responsáveis pelo odor axilar pungente dos esteróides androgênicos (JACKMAN & NOBLE, 1983). O método mais eficaz de inibir a produção de exoenzimas bacterianas responsáveis pelo mau odor axiliar são as composições desodorantes. O método consiste em produzir um veículo cosmético (emulsão, suspensão em gás, composição hidroalcoólica, entre outros) e adicionar um ativo desodorante dissolvido ou em suspensão, que tem como propriedade a inibição da produção das exoenzimas bacterianas que levam à produção dos cheiros desagradáveis. (EIGEN & FROEBE, 1997). Neste trabalho testamos a suscetibilidade de três espécies de bactérias semelhantes às que compõem a microbiota permanente das axilas (Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228 e Corynebacterium xerosis ATCC 373), frente a três formulações cosméticas hidroalcoólicas de desodorantes em spray contendo ativos desodorantes. Utilizamos também a linhagem Escherichia coli ATCC 8739, pois esta enterobactéria pode estar presente nas axilas principalmente pelo contato destas com as mãos (BORICK & SARRA, 1960). A metodologia utilizada para os testes foi baseada na norma M7-A7 (CLSI, 2006), que trata dos testes de sensibilidade a agentes antimicrobianos por diluição para bactérias de crescimento aeróbico. A fórmula desodorante que teve melhor desempenho sobre...

An Isoflavone From Dipteryx Alata Vogel Is Active Against The In Vitro Neuromuscular Paralysis Of Bothrops Jararacussu Snake Venom And Bothropstoxin I, And Prevents Venom-induced Myonecrosis.

Snakebite is a neglected disease and serious health problem in Brazil, with most bites being caused by snakes of the genus Bothrops. Although serum therapy is the primary treatment for systemic envenomation, it is generally ineffective in neutralizing the local effects of these venoms. In this work, we examined the ability of 7,8,3'-trihydroxy-4'-methoxyisoflavone (TM), an isoflavone from Dipteryx alata, to neutralize the neurotoxicity (in mouse phrenic nerve-diaphragm preparations) and myotoxicity (assessed by light microscopy) of Bothrops jararacussu snake venom in vitro. The toxicity of TM was assessed using the Salmonella microsome assay (Ames test). Incubation with TM alone (200 μg/mL) did not alter the muscle twitch tension whereas incubation with venom (40 μg/mL) caused irreversible paralysis. Preincubation of TM (200 μg/mL) with venom attenuated the venom-induced neuromuscular blockade by 84% ± 5% (mean ± SEM; n = 4). The neuromuscular blockade caused by bothropstoxin-I (BthTX-I), the major myotoxic PLA2 of this venom, was also attenuated by TM. Histological analysis of diaphragm muscle incubated with TM showed that most fibers were preserved (only 9.2% ± 1.7% were damaged; n = 4) compared to venom alone (50.3% ± 5.4% of fibers damaged; n = 3), and preincubation of TM with venom significantly attenuated the venom-induced damage (only 17% ± 3.4% of fibers damaged; n = 3; p < 0.05 compared to venom alone). TM showed no mutagenicity in the Ames test using Salmonella strains TA98 and TA97a with (+S9) and without (-S9) metabolic activation. These findings indicate that TM is a potentially useful compound for antagonizing the neuromuscular effects (neurotoxicity and myotoxicity) of B. jararacussu venom.

In Vitro And In Vivo Anti-angiogenic Effects Of Hydroxyurea.

Hydroxyurea (HU), or hydroxycarbamide, is used for the treatment of some myeloproliferative and neoplastic diseases, and is currently the only drug approved by the FDA for use in sickle cell disease (SCD). Despite the relative success of HU therapy for SCD, a genetic disorder of the hemoglobin β chain that results in red-cell sickling, hemolysis, vascular inflammation and recurrent vasoocclusion, the exact mechanisms by which HU actuates remain unclear. We hypothesized that HU may modulate endothelial angiogenic processes, with important consequences for vascular inflammation. The effects of HU (50-200 μM; 17-24 h) on endothelial cell functions associated with key steps of angiogenesis were evaluated using human umbilical vein endothelial cell (HUVEC) cultures. Expression profiles of the HIF1A gene and the miRNAs 221 and 222, involved in endothelial function, were also determined in HUVECs following HU administration and the direct in vivo antiangiogenic effects of HU were assessed using a mouse Matrigel-plug neovascularization assay. Following incubation with HU, HUVECs exhibited high cell viability, but displayed a significant 75% inhibition in the rate of capillary-like-structure formation, and significant decreases in proliferative and invasive capacities. Furthermore, HU significantly decreased HIF1A expression, and induced the expression of miRNA 221, while downregulating miRNA 222. In vivo, HU reduced vascular endothelial growth factor (VEGF)-induced vascular development in Matrigel implants over 7 days. Findings indicate that HU is able to inhibit vessel assembly, a crucial angiogenic process, both in vitro and in vivo, and suggest that some of HU's therapeutic effects may occur through novel vascular mechanisms.

Carotenoids Are Effective Inhibitors Of In Vitro Hemolysis Of Human Erythrocytes, As Determined By A Practical And Optimized Cellular Antioxidant Assay.

β-Carotene, zeaxanthin, lutein, β-cryptoxanthin, and lycopene are liposoluble pigments widely distributed in vegetables and fruits and, after ingestion, these compounds are usually detected in human blood plasma. In this study, we evaluated their potential to inhibit hemolysis of human erythrocytes, as mediated by the toxicity of peroxyl radicals (ROO•). Thus, 2,2'-azobis (2-methylpropionamidine) dihydrochloride (AAPH) was used as ROO• generator and the hemolysis assay was carried out in experimental conditions optimized by response surface methodology, and successfully adapted to microplate assay. The optimized conditions were verified at 30 × 10(6) cells/mL, 17 mM of AAPH for 3 h, at which 48 ± 5% of hemolysis was achieved in freshly isolated erythrocytes. Among the tested carotenoids, lycopene (IC(50) = 0.24 ± 0.05 μM) was the most efficient to prevent the hemolysis, followed by β-carotene (0.32 ± 0.02 μM), lutein (0.38 ± 0.02 μM), and zeaxanthin (0.43 ± 0.02 μM). These carotenoids were at least 5 times more effective than quercetin, trolox, and ascorbic acid (positive controls). β-Cryptoxanthin did not present any erythroprotective effect, but rather induced a hemolytic effect at the highest tested concentration (3 μM). These results suggest that selected carotenoids may have potential to act as important erythroprotective agents by preventing ROO•-induced toxicity in human erythrocytes.

Bay 41-2272, A Soluble Guanylate Cyclase Stimulator, Relaxes Isolated Human Ureter In A Standardized In Vitro Model.

To characterize the relaxation induced by BAY 41-2272 in human ureteral segments. Ureter specimens (n = 17) from multiple organ human deceased donors (mean age 40 ± 3.2 years, male/female ratio 2:1) were used to characterize the relaxing response of BAY 41-2272. Immunohistochemical analysis for endothelial and neuronal nitric oxide synthase, guanylate cyclase stimulator (sGC) and type 5 phosphodiesterase was also performed. The potency values were determined as the negative log of the molar to produce 50% of the maximal relaxation in potassium chloride-precontracted specimens. The unpaired Student t test was used for the comparisons. Immunohistochemistry revealed the presence of endothelial nitric oxide synthase in vessel endothelia and neuronal nitric oxide synthase in urothelium and nerve structures. sGC was expressed in the smooth muscle and urothelium layer, and type 5 phosphodiesterase was present in the smooth muscle only. BAY 41-2272 (0.001-100 μM) relaxed the isolated ureter in a concentration dependent manner, with a potency and maximal relaxation value of 5.82 ± 0.14 and 84% ± 5%, respectively. The addition of nitric oxide synthase and sGC inhibitors reduced the maximal relaxation values by 21% and 45%, respectively. However, the presence of sildenafil (100 nM) significantly potentiated (6.47 ± 0.10, P <.05) this response. Neither glibenclamide or tetraethylammonium nor ureteral urothelium removal influenced the relaxation response by BAY 41-2272. BAY 41-2272 relaxes the human isolated ureter in a concentration-dependent manner, mainly by activating the sGC enzyme in smooth muscle cells rather than in the urothelium, although a cyclic guanosine monophosphate-independent mechanism might have a role. The potassium channels do not seem to be involved.

Membrane Lipid Profile Monitored By Mass Spectrometry Detected Differences Between Fresh And Vitrified In Vitro-produced Bovine Embryos.

Summary This study aimed to evaluate the impact of vitrification on membrane lipid profile obtained by mass spectrometry (MS) of in vitro-produced bovine embryos. Matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) has been used to obtain individual embryo membrane lipid profiles. Due to conditions of analysis, mainly membrane lipids, most favorably phosphatidylcholines (PCs) and sphingomyelins (SMs) have been detected. The following ions described by their mass-to-charge ratio (m/z) and respective attribution presented increased relative abundance (1.2-20×) in the vitrified group: 703.5 [SM (16:0) + H]+; 722.5 [PC (40:3) + Na]+; 758.5 [PC (34:2) + H]+; 762.5 [PC (34:0) + H]+; 790.5 [PC (36:0) + H]+ and 810.5 [PC (38:4) + H]+ and/or [PC (36:1) + Na]+. The ion with a m/z 744.5 [PCp (34:1) and/or PCe (34:2)] was 3.4-fold more abundant in the fresh group. Interestingly, ions with m/z 722.5 or 744.5 indicate the presence of lipid species, which are more resistant to enzymatic degradation as they contain fatty acyl residues linked through ether type bonds (alkyl ether or plasmalogens, indicated by the lowercase 'e' and 'p', respectively) to the glycerol structure. The results indicate that cryopreservation impacts the membrane lipid profile, and that these alterations can be properly monitored by MALDI-MS. Membrane lipids can therefore be evaluated by MALDI-MS to monitor the effect of cryopreservation on membrane lipids, and to investigate changes in lipid profile that may reflect the metabolic response to the cryopreservation stress or changes in the environmental conditions.

Effect Of Daily Use Of An Enzymatic Denture Cleanser On Candida Albicans Biofilms Formed On Polyamide And Poly(methyl Methacrylate) Resins: An In Vitro Study.

Candida biofilms on denture surfaces are substantially reduced after a single immersion in denture cleanser. However, whether this effect is maintained when dentures are immersed in cleanser daily is unclear. The purpose of this study was to evaluate the effect of the daily use of enzymatic cleanser on Candida albicans biofilms on denture base materials. The surfaces of polyamide and poly(methyl methacrylate) resin specimens (n=54) were standardized and divided into 12 groups (n=9 per group), according to study factors (material type, treatment type, and periods of treatment). Candida albicans biofilms were allowed to form over 72 hours, after which the specimens were treated with enzymatic cleanser once daily for 1, 4, or 7 days. Thereafter, residual biofilm was ultrasonically removed and analyzed for viable cells (colony forming units/mm(2)) and enzymatic activity (phospholipase, aspartyl-protease, and hemolysin). Factors that interfered with the response variables were analyzed by 3-way ANOVA with the Holm-Sidak multiple comparison method (α=.05). Polyamide resin presented more viable cells of Candida albicans (P<.001) for both the evaluated treatment types and periods. Although enzymatic cleansing significantly (P<.001) reduced viable cells, daily use did not maintain this reduction (P<.001). Phospholipase activity significantly increased with time (P<.001) for both materials and treatments. However, poly(methyl methacrylate) based resin (P<.001) and enzymatic cleansing treatment (P<.001) contributed to lower phospholipase activity. Aspartyl-protease and hemolysin activities were not influenced by study factors (P>.05). Although daily use of an enzymatic cleanser reduced the number of viable cells and phospholipase activity, this treatment was not effective against residual biofilm over time.

Design And Synthesis Of N-acylated Aza-goniothalamin Derivatives And Evaluation Of Their In Vitro And In Vivo Antitumor Activity.

Herein we describe the synthesis of a focused library of compounds based on the structure of goniothalamin (1) and the evaluation of the potential antitumor activity of the compounds. N-Acylation of aza-goniothalamin (2) restored the in vitro antiproliferative activity of this family of compounds. 1-(E)-But-2-enoyl-6-styryl-5,6-dihydropyridin-2(1H)-one (18) displayed enhanced antiproliferative activity. Both goniothalamin (1) and derivative 18 led to reactive oxygen species generation in PC-3 cells, which was probably a signal for caspase-dependent apoptosis. Treatment with derivative 18 promoted Annexin V/7-aminoactinomycin D double staining, which indicated apoptosis, and also led to G2 /M cell-cycle arrest. In vivo studies in Ehrlich ascitic and solid tumor models confirmed the antitumor activity of goniothalamin (1), without signs of toxicity. However, derivative 18 exhibited an unexpectedly lower in vivo antitumor activity, despite the treatments being administered at the same site of inoculation. Contrary to its in vitro profile, aza-goniothalamin (2) inhibited Ehrlich tumor growth, both on the ascitic and solid forms. Our findings highlight the importance of in vivo studies in the search for new candidates for cancer treatment.

Staphylococcus Aureus Enterotoxins A And B Inhibit Human And Mice Eosinophil Chemotaxis And Adhesion In Vitro.

Staphylococcus aureus aggravates the allergic eosinophilic inflammation. We hypothesized that Staphylococcus aureus-derived enterotoxins directly affect eosinophil functions. Therefore, this study investigated the effects of Staphylococcal enterotoxins A and B (SEA and SEB) on human and mice eosinophil chemotaxis and adhesion in vitro, focusing on p38 MAPK phosphorylation and intracellular Ca(2+) mobilization. Eosinophil chemotaxis was evaluated using a microchemotaxis chamber, whereas adhesion was performed in VCAM-1 and ICAM-1-coated plates. Measurement of p38 MAPK phosphorylation and intracellular Ca(2+) levels were monitored by flow cytometry and fluorogenic calcium-binding dye, respectively. Prior incubation (30 to 240 min) of human blood eosinophils with SEA (0.5 to 3 ng/ml) significantly reduced eotaxin-, PAF- and RANTES-induced chemotaxis (P<0.05). Likewise, SEB (1 ng/ml, 30 min) significantly reduced eotaxin-induced human eosinophil chemotaxis (P<0.05). The reduction of eotaxin-induced human eosinophil chemotaxis by SEA and SEB was prevented by anti-MHC monoclonal antibody (1 μg/ml). In addition, SEA and SEB nearly suppressed the eotaxin-induced human eosinophil adhesion in ICAM-1- and VCAM-1-coated plates. SEA and SEB prevented the increases of p38 MAPK phosphorylation and Ca(2+) levels in eotaxin-activated human eosinophils. In separate protocols, we evaluated the effects of SEA on chemotaxis and adhesion of eosinophils obtained from mice bone marrow. SEA (10 ng/ml) significantly reduced the eotaxin-induced chemotaxis along with cell adhesion to both ICAM-1 and VCAM-1-coated plates (P<0.05). In conclusion, the inhibition by SEA and SEB of eosinophil functions (chemotaxis and adhesion) are associated with reductions of p38 MAPK phosphorylation and intracellular Ca(2+) mobilization.

A New Platinum Complex With Tryptophan: Synthesis, Structural Characterization, Dft Studies And Biological Assays In Vitro Over Human Tumorigenic Cells.

A new platinum(II) complex with the amino acid L-tryptophan (trp), named Pt-trp, was synthesized and characterized. Elemental, thermogravimetric and ESI-QTOF mass spectrometric analyses led to the composition [Pt(C11H11N2O2)2]⋅6H2O. Infrared spectroscopic data indicate the coordination of trp to Pt(II) through the oxygen of the carboxylate group and also through the nitrogen atom of the amino group. The (13)C CP/MAS NMR spectroscopic data confirm coordination through the oxygen atom of the carboxylate group, while the (15)N CP/MAS NMR data confirm coordination of the nitrogen of the NH2 group to the metal. Density functional theory (DFT) studies were applied to evaluate the cis and trans coordination modes of trp to platinum(II). The trans isomer was shown to be energetically more stable than the cis one. The Pt-trp complex was evaluated as a cytotoxic agent against SK-Mel 103 (human melanoma) and Panc-1 (human pancreatic carcinoma) cell lines. The complex was shown to be cytotoxic over the considered cells.

Liposomal Lidocaine Gel For Topical Use At The Oral Mucosa: Characterization, In Vitro Assays And In Vivo Anesthetic Efficacy In Humans.

To characterize liposomal-lidocaine formulations for topical use on oral mucosa and to compare their in vitro permeation and in vivo anesthetic efficacy with commercially available lidocaine formulations. Large unilamellar liposomes (400 nm) containing lidocaine were prepared using phosphatidylcholine, cholesterol, and α-tocoferol (4:3:0.07, w:w:w) and were characterized in terms of membrane/water partition coefficient, encapsulation efficiency, size, polydispersity, zeta potential, and in vitro release. In vitro permeation across pig palatal mucosa and in vivo topical anesthetic efficacy on the palatal mucosa in healthy volunteers (double-blinded cross-over, placebo controlled study) were performed. The following formulations were tested: liposome-encapsulated 5% lidocaine (Liposome-Lido5); liposome-encapsulated 2.5% lidocaine (Liposome-Lido2.5); 5% lidocaine ointment (Xylocaina®), and eutectic mixture of lidocaine and prilocaine 2.5% (EMLA®). The Liposome-Lido5 and EMLA showed the best in vitro permeation parameters (flux and permeability coefficient) in comparison with Xylocaina and placebo groups, as well as the best in vivo topical anesthetic efficacy. We successfully developed and characterized a liposome encapsulated 5% lidocaine gel. It could be considered an option to other topical anesthetic agents for oral mucosa.

Preparation, Characterization And In Vitro Digestibility Of Gellan And Chitosan-gellan Microgels.

Gellan microgels with potential application in delivery systems were obtained by physically cross-linked gellan gum. The microgels were produced by atomization followed by ionotropic gelation using CaCl2 (gellan/Ca) or KCl (gellan/K) as hardening agent and part of them were coated with chitosan in order to improve their resistance to gastric digestion. Size distribution, morphology and zeta potential of microgels were evaluated before and after in vitro digestion process. The long term stability was also evaluated. Spherical microparticles were obtained at gellan concentration above 0.6% w/w, showing average size among 70-120 μm. Most of the coated and uncoated microgels showed stability in aqueous media, except the uncoated gellan/K microgel. The in vitro digestion evaluation showed that all particles maintained their size and shape after the gastric digestion step. However, the enteric digestion caused disintegration of microgels indicating their potential application for enteric delivery systems. The chitosan-coated microgels showed lower degree of fragmentation when compared to the uncoated microgels, indicating that the coating process enable a better control of microgels releasing properties during the enteric digestion.