Compatibility and efficiency of preservatives in emulsive cosmetics containing high surfactant content

Abstract The objective of this study was to determine the influence of nonionic surfactants on the effectiveness of preservatives used in emulsions containing high surfactant content. Mixtures of different concentrations were prepared between polyethoxylated (40) hydrogenated castor oil (PHCO) and polyoxyethylene sorbitan monooleate (PSO), with methylparaben, phenoxyethanol, methylparaben, ethylparaben, propylparaben, and isobutylparaben (PMEPBI) blend, phenoxyethanol and benzoic acid (BP) blend, and phenoxyethanol and caprylyl glycol (PC) blend. Subsequently, the compatibility of the formulation ingredients and the effectiveness of the preservatives were evaluated by the challenge test. It was found that PHCO and PSO inactivated the antimicrobial action of methylparaben and PMEPBI. Paraben-free preservatives BP and PC had less influence on surfactants than systems containing parabens. When incorporated into microemulsions and nanoemulsions containing 40% and 20% surfactants, methylparaben and BP 0.2% and 0.5% were only effective against Aspergillus niger. The PMEPBI 0.2% was effective as a preservative in nanoemulsified formulations against A. niger, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. The results demonstrate that the efficacy of the preservative system in formulations containing nonionic surfactant excipients depends on the type of excipient, the components of the formulation, the preservative systems composition, the excipient to preservative ratio, and the availability in the formulation.

Desenvolvimento e caracterização de nanopartículas de poli (n-butil cianoacrilato) contendo a associação lamivudina e zidovudina / Development and characterization of poly (n- butyl cyanoacrylate) nanoparticles containing the combination of lamivudine and zidovudine

A zidovudina (AZT), fármaco antirretroviral utilizado no tratamento da AIDS, apresenta biodisponibilidade oral em torno de 60% e seu uso prolongado pode ocasionar efeitos tóxicos e tolerância ao tratamento. A lamivudina (3TC), apesar de demonstrar menor citotoxicidade e menor resistência viral, é considerada também menos potente. A associação entre os dois fármacos é recomendável em função da boa resposta terapêutica e maior adesão ao tratamento. As nanopartículas são uma alternativa para melhorar a biodisponibilidade e o transporte de fármacos sobretudo através da BHE. Nesse sentido, as nanopartículas poliméricas de poli (n-butil cianoacrilato) (PBCA) apresentam grande potencial para melhoria das características farmacêuticas, além de possibilitar resultados terapêuticos mais eficazes por meio da modificação de sua superfície, direcionando o fármaco ao sítio alvo. Diante do exposto, foram desenvolvidas nanopartículas de PBCA contendo a associação lamivudina e zidovudina (3TC/AZT) revestidas com polissorbato 80 (Ps80). As nanopartículas obtidas foram caracterizadas e apresentaram resultados coerentes aos encontrados na literatura. Após a encapsulação dos fármacos e o revestimento com Ps80, notou-se um aumento no diâmetro médio e o potencial Zeta foi próximo de zero. Esses resultados juntamente com a análise de SAXS comprovam o revestimento das nanopartículas de PBCA. Os dados de DSC e TG/DTG mostram que a encapsulação foi eficiente para a estabilização térmica dos fármacos. Foi desenvolvido e validado o método analítico por CLAE, a fim de determinar a eficiência de encapsulação. A validação do método analítico para quantificação simultânea do 3TC e AZT, tanto nas nanopartículas de PBCA quanto nas nanopartículas revestidas, apresentou linearidade, especificidade, precisão e exatidão adequadas de acordo com as normativas. A porcentagem de encapsulação dos fármacos foi igual a 44,45% e 30,44%. As nanopartículas de PBCA e PBCAPs80, em concentrações abaixo de 100 µg/mL, apresentaram viabilidade celular superior a 70% em células Caco-2, comprovando que o sistema apresenta baixa citotoxicidade, o que representa uma alternativa promissora para a encapsulação de fármacos antirretrovirais e consequente progresso no tratamento da AIDS

Zidovudine (AZT), which is an anti-retroviral drug used in the treatment of AIDS, has oral bioavailability around 60% and its prolonged use can cause toxic effects and tolerance to the treatment. Lamivudine (3TC), although it has lower cytotoxicity and lower viral resistance, is also considered less potent. The association between these two drugs is recommended based on the good therapeutic response and greater adherence to treatment. Nanoparticles are an alternative to improve the bioavailability and the transport of drugs, particularly through the BBB. Thus, the polymeric nanoparticles of poly (n-butyl cyanoacrylate) (PBCA) have great potential for improving the pharmaceutical characteristics, besides enabling more effective therapeutic results through the modification of its surface, directing the drug to the target site. That being said, PBCA nanoparticles were developed containing the association of lamivudine and zidovudine (3TC/AZT) coated with polysorbate 80 (Ps80). Nanoparticles obtained were characterized and presented coherent results when compared to those found in the literature. After the encapsulation of pharmaceuticals and Ps80 coating, it was noted an increase in the average diameter and Zeta potential was close to zero. These results along with the SAXS analysis proved the coating of the PBCA nanoparticles. The data of DSC and TG/DTG show that encapsulation was efficient for thermal stabilization of pharmaceuticals. An analytical method by HPLC was developed and validated to determine the efficiency of encapsulation. The validation of the analytical method for simultaneous quantification of 3TC and AZT, in both the PBCA nanoparticles and coated nanoparticles, presented as in linearity, specificity, precision and accuracy according to the regulations. The percentage of drug encapsulation was equal to 44.45% and 30.44%. The nanoparticles of PBCA and PBCA-Ps80, at concentrations below 100 µg/ml, presented cell viability greater than 70% in Caco-2 cells, proving that the system has low cytotoxicity, which represents a promising alternative for the encapsulation of antiretroviral drugs and consequent progress in AIDS treatment

Antimicrobial effect of MTAD, Tetraclean, Cloreximid, and sodium hypochlorite on three common endodontic pathogens.

Objectives: The aim of this in vitro study was to evaluate the antimicrobial action of BioPure MTAD (Dentsply Tulsa Dental, Johnson City, TN), Tetraclean, Cloreximid (a mixture of Chlorhexidine (CHX) digluconate and Cetrimide), and 5.25% NaOCl (Ogna Laboratori Farmaceutici, Milano, Italy) against selected endodontic pathogens (Enterococcus faecalis, Porphyromonas gingivalis, and Prevotella intermedia). Materials and Methods: The agar plate diffusion procedure was used to observe the antimibrobial activity of irrigants. Results: Statistical analysis revealed significant effects of the different irrigants on the bacteria colonies. Treatment with 5.25% NaOCl induced a larger zone of microbial inhibition in Prevotella intermedia and Porphyromonas gingivalis (Tukey HSD post-test, P = 0.0001) when compare to MTAD, Tetraclean and CHX. Anyway, MTAD and Tetraclean were more effective to inhibit bacterial growth compared to CHX (P < 0.0001, Tukey HSD post-test). Furthermore, post hoc analysis revealed that MTAD and Tetraclean induced the largest zone of microbial inhibition of Enterococcus faecalis cultured under both aerobic and anaerobic conditions, when compared with 2% CHX and NaOCl (P < 0.0001, Tukey HSD post-test). The control group showed no microbial inhibition. Conclusion: 5.25% NaOCl showed a high antimicrobial activity against anaerobic bacteria. MTAD and Tetraclean showed a high action against both, strictly anaerobic and facultative anaerobic bacteria. Chlorexidine + Cetrimide (Cloreximid) showed the lowest antibacterial activity against both, facultative and strictly anaerobic bacteria tested.

Production of fungal cell wall degrading enzymes by a biocontrol strain of Bacillus subtilis AF 1.

Fungal cell wall degrading chitinases and glucanases attained significance in agriculture, medicine, and environment management. The present study was conducted to describe the optimum conditions required for the production of beta-1,4-N-acetyl glucosaminidase (NAGase) and beta-1,3-glucanase by a biocontrol strain of Bacillus subtilis AF 1. B. subtilis AF 1 was grown in minimal medium with colloidal chitin (3.0%) and yeast extract (0.3% YE ) and incubated at pH 7.0 and 30 degrees C on constant shaker at 180 rpm for 6 days produced highest amounts of NAGase. Presence of 0.5 mM of phenyl methyl sulfonyl fluoride (PMSF) and 0.04% of Tween 20 further improved the enzyme production. B. subtilis AF 1 grown in minimal medium with laminarin (1%) and yeast extract (0.3%) for 3 days produced maximum amount of beta-1,3-glucanase. These conditions can be further scaled-up for large-scale production of NAGase and beta-1,3-glucanase by B. subtilis AF 1.

Amiodarona causa vasodilatação dependente do endotélio em artérias coronárias caninas / Amiodarone causes endothelium-dependent vasodilation in canine coronary arteries

OBJETIVO: Avaliar os efeitos vasodilatadores da amiodarona em artérias coronárias caninas empregando soluções de amiodarona dissolvida em polisorbato 80 ou em água. MÉTODOS: Anéis de artéria coronária, com e sem o endotélio íntegro, foram imersos em solução de krebs e conectadas a um transdutor para aferição de força isométrica promovida por contração vascular. As artérias foram expostas a concentrações crescentes de polisorbato 80, amiodarona dissolvida em água, amiodarona dissolvida em polisorbato 80 e uma apresentação comercial da amiodarona (Cordarone®). Os experimentos foram conduzidos na presença e na ausência dos seguintes bloqueadores enzimáticos: apenas indometacina, Nω-nitro-L-arginina associada à indometacina e apenas Nω-nitro-L-arginina. RESULTADOS: O polisorbato 80 causou pequeno relaxamento não dependente do endotélio. O Cordarone®, a amiodarona dissolvida em água e em polisorbato 80 promoveram relaxamento dependente do endotélio, que foi de maior magnitude para a amiodarona dissolvida em polisorbato e para o Cordarone®. Apenas a associação de indometacina com a Nω-nitro-L-arginina foi capaz de abolir o relaxamento dependente do endotélio provocado pela amiodarona dissolvida em polisorbato 80. CONCLUSAO: Os resultados obtidos indicam que a vasodilatação promovida pela amiodarona em artérias coronárias caninas é causada principalmente pela estimulação da liberação de óxido nítrico e fatores endoteliais relaxantes dependentes das ciclo-oxigenases.

Potentiality of a new compound for in vitro differentiation between halophilic and non-halophilic vibrios.

Sensitivity of 21 halophilic vibrios and 16 clinical isolates of non-halophilic vibrios was determined against a new possible antivibrio agent, a pyrimidine analogue, 4, 6-dimethylpyrimidine -2-thiol (4,6-DMPT). It appeared to be a vibriocidal agent, having a mean MIC and MBC of 32 microg/ml for halophilic strains and 64 microg/ml for non-halophilic strains and an LD50 of 300 mg/Kg body weight of mice. Thus, 4,6-DMPT may help an in vitro distinction between halophilic and non-halophilic vibrios. Sensitivity of these strains was also studied with respect to pteridine, crystal violet and Tween 80 hydrolysis as further markers distinguishing between these 2 groups which could also be differentiated by their growth on TCBS or/and CLED media.

Interaction of Triton X-100 with acyl pocket of butyrylcholinesterase: effect on esterase activity and inhibitor sensitivity of the enzyme.

The effect of non-ionic detergents like Triton X-100, Lubrol PX, Brij 35 and Tween 80 on the esterase activity and inhibitor sensitivity of human serum butyrylcholinesterase (BuChE) were studied. The results showed that though BuChE is not a detergent dependent enzyme, the esterase activity and inhibitor sensitivity of it can be modulated by the presence of detergents. All the detergents caused a marginal activation of the esterase activity. The presence of Lubrol PX, Brij 35 or Tween 80 did not affect the 50% molar inhibition concentration (IC50) of the inhibitors tested. But in the presence of Triton X-100 the IC50 values were increased for neostigmine, eserine and tetraisopropylpyrophosphoramide (acylation site interacting inhibitors), whereas for inhibitors like ethopropazine, imipramine and procainamide (choline binding pocket specific inhibitors) the IC50 values were unaltered. In addition, in the presence of Triton X-100 the bimolecular reaction constant for phosphorylation reaction (ki) of BuChE for the acyl pocket specific tetraisopropylpyrophosphoramide was reduced. Triton X-100 partially protected BuChE against this tetraisopropylpyrophosphoramide inactivation. These results indicate that Triton X-100 by interacting with the acyl pocket hydrophobic region is able to activate the esterase activity of BuChE. Further it reduces the capacity of the enzyme to react with inhibitors that inactivate it by interacting with the serine residue of the acylation site.

Morphological identification of Candida species on glucose agar, rice extract agar and corn meal agar with and without Tween-80.

A comparative study for the identification of 32 known strains of Candida species on the basis of morphology on glucose agar, rice extract agar and corn meal agar with and without Tween 80 revealed that when Tween 80 is incorporated in the media identification is possible for 96.8% of the species within 48 hours on rice extract agar and for 96.8% of the species within 48 hours on rice extract agar and for 90.6% of the species on glucose agar. The germ tubes and chlamydospores were also produced more on rice extract agar than on 0.1% glucose agar. Rice extract agar with Tween 80 can be used as single medium for morphologic identification of Candida species. The inoculated medium is first incubated at 37 degrees C for 3 hours and examined for germ tube formation and then incubated at 25 degrees C for 24 to 72 hours and examined for appearance of chlamydospores and mycelial morphology.

Comparative effects of mast cell degranulators on perfused systemic blood vessels of Bufo melanostictus and Rana tigrina.

Three agents known to induce release of mast cell constituents, viz. polymyxin, compound 48/80 and polysorbate-80, were evaluated for effect on perfused blood vessels of R. tigrina and B. melanostictus. The mast cell degranulators caused vasoconstriction in frog and toad, except that for P-80 whose responses in toad were equivocal. Toads showed a general low responsiveness in comparison to frogs. Pharmacologic intervention with pheniramine, metergoline, hydergine, atropine and mecamylamine, respectively ruled out role of histamine, 5-HT, catecholamine or acetylcholine or even autonomic mechanisms in the above phenomena. The observations are suggestive of phylogenetic differences in biochemical profile of mast cells in amphibian species.

Growth of Mycobacterium leprae in a redox system: II. Further improvements in the system and growth efficiency.

Improvement of the Redox System for growth of M. leprae as brought about by modification in the concentration and mode of preparation of individual media constituents, and by addition of newer substances, is being reported. A structural modification in the construction of the Thunberg's tubes and flasks that are used as culture vessels, has been introduced for ease of handling. Vitamin E (alpha-tocopherol) has been found to be useful. Concentrations of Liposomes and Gelatin in the medium could be reduced by at least five folds, considerably easing thereby smearing and harvesting of cultures. Dimercaptopropanol British Anti-lewisite or BAL) has been used, but its usefulness or otherwise is yet to be determined conclusively. The basis of intracellular parasitism of M. leprae has been discussed.