Digestion of surfactants does not affect their ability to inhibit P-gp-mediated transport in vitro.

While various non-ionic surfactants at low concentrations have been shown to increase the transport of P-gp substrates in vitro, in vivo studies in rats have shown that a higher surfactant concentration is needed to increase the oral absorption of e.g. the P-gp substrates digoxin and etoposide. The aim of the present study was to investigate if intestinal digestion of surfactants could be the reason for this deviation between in vitro and in vivo data. Therefore, Kolliphor EL, Brij-L23, Labrasol and polysorbate 20 were investigated for their ability to inhibit P-gp and increase digoxin absorption in vitro. Transport studies were performed in Caco-2 cells, while P-gp inhibition and cell viability assays were performed in MDCKII-MDR1 cells. Polysorbate 20, Kolliphor EL and Brij-L23 increased absorptive transport and decreased secretory digoxin transport in Caco-2 cells, whereas only polysorbate 20 and Brij-L23 showed P-gp inhibiting properties in the MDCKII-MDR1 cells. Polysorbate 20 and Brij-L23 were chosen for in vitro digestion prior to transport- or P-gp inhibiting assays. Brij-L23 was not digestible, whereas polysorbate 20 reached a degree of digestion around 40%. Neither of the two surfactants showed any significant difference in their ability to affect absorptive or secretory transport of digoxin after pre-digestion. Furthermore, the P-gp inhibiting effects of polysorbate 20 were not decreased significantly. In conclusion, the mechanism behind the non-ionic surfactant mediated in vitro P-gp inhibition seemed independent of the intestinal digestion and the results presented here did not suggest it to be the cause of the observed discrepancy between in vitro and in vivo.

Combination drug therapy by herbal nanomedicine prevent multidrug resistance protein 1: promote apoptosis in Lung Carcinoma.

Given the numerous adverse effects of lung cancer treatment, more research on non-toxic medications is urgently needed. Curcumin (CUR) and berberine (BBR) combat drug resistance by controlling the expression of multidrug resistant pump (MDR1). Fascinatingly, combining these medications increases the effectiveness of preventing lung cancer. Their low solubility and poor stability, however, restrict their therapeutic efficacy. Because of the improved bioavailability and increased encapsulation effectiveness of water-insoluble medicines, surfactant-based nanovesicles have recently received a great deal of attention. The current study sought to elucidate the Combination drug therapy by herbal nanomedicine prevent multidrug resistance protein 1: promote apoptosis in Lung Carcinoma. The impact of several tween (20, 60, and 80) types with varied hydrophobic tails on BBR/CUR-TNV was evaluated. Additionally, the MDR1 activity and apoptosis rate of the BBR/CUR-TNV combination therapy were assessed. The encapsulation effectiveness of TNV was affected by the type of tween. With the TNV made from tween 60, cholesterol, and PEG (47.5: 47.5:5), more encapsulation effectiveness was attained. By combining CUR with BBR, especially when given in TNV, apoptosis increased. Additionally, when CUR and BBR were administered in combination, they significantly reduced the risk of MDR1 development. The current work suggests that the delivery of berberine and curcumin as a combination medication therapy via tween-based nanovesicles may be a potential lung cancer treatment.

Surfactants for stabilization of dermal emulsions and their skin compatibility under UVA irradiation: Diacyl phospholipids and polysorbate 80 result in high viability rates of primary human skin cells.

Phospholipids are versatile formulation compounds with high biocompatibility. However, no data on their effect on skin in combination with UVA radiation exist. Thus, it was the aim of this work to (i) develop o/w nanoemulsions (NEs) differing in surfactant type and to investigate their physicochemical stability at different storage temperatures, (ii) establish a standardized protocol for in vitro phototoxicity testing using primary human skin cells and (iii) investigate the phototoxicity of amphoteric phospholipids (S45, S75, E80, S100, LPC80), sodium lauryl ether sulfate (SLES) and polysorbate 80 (PS80). Satisfying systems were developed with all surfactants except S100 due to low zeta potential (-21.4 mV ± 4.69). SLES and PS80-type NEs showed the highest stability after eight weeks; temperature-dependent variations in storage stability were most noticeable for phospholipid surfactants. For phospholipid-based NEs, higher phosphatidylcholine content led to unstable formulations. Phototoxicity assays with primary skin fibroblasts confirmed the lack of UVA-related phototoxicity but revealed cytotoxic effects of LPC80 and SLES, resulting in cell viability as low as 2.7 % ±0.78 and 1.9 % ±1.57 compared to the control. Our findings suggest that surfactants S45, S75 and PS80 are the most promising candidates for skin-friendly emulsifiers in sensitive applications involving exposure to UV light.

Effect of cationic surfactant on the physicochemical and antibacterial properties of colloidal systems (emulsions and microemulsions).

Colloidal systems have been used to encapsulate, protect and release essential oils in mouthwashes. In this study, we investigated the effect of cetylpyridinium chloride (CPC) on the physicochemical properties and antimicrobial activity of oil-in-water colloidal systems containing tea tree oil (TTO) and the nonionic surfactant polysorbate 80. Our main aim was to evaluate whether CPC could improve the antimicrobial activity of TTO, since this activity is impaired when this essential oil is encapsulated with polysorbate 80. These systems were prepared with different amounts of TTO (0-0.5% w/w) and CPC (0-0.5% w/w), at a final concentration of 2% (w/w) polysorbate 80. Dynamic light scattering (DLS) results revealed the formation of oil-swollen micelles and oil droplets as a function of TTO concentration. Increases in CPC concentrations led to a reduction of around 88% in the mean diameter of oil-swollen micelles. Although this variation was of only 20% for the oil droplets, the samples appearance changed from turbid to transparent. The surface charge of colloidal structures was also markedly affected by the CPC as demonstrated by the transition in zeta potential from slightly negative to highly positive values. Electron paramagnetic resonance (EPR) studies showed that this transition is followed by significant increases in the fluidity of surfactant monolayer of both colloidal structures. The antimicrobial activity of colloidal systems was tested against a Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureaus) bacteria. Our results revealed that the inhibition of bacterial growth is observed for the same CPC concentration (0.05% w/w for E. coli and 0.3% w/w for S. aureus) regardless of TTO content. These findings suggest that TTO may not act as an active ingredient in polysorbate 80 containing mouthwashes.

Evaluation of Drug-Loaded and Surface-Adsorbed DNase/Tween-80 Solid Lipid Nanoparticles against Staphylococcus aureus Biofilms.

The aim of this study was to explore the suitability of Tween-80 or DNase I adsorbed onto the surface of gentamicin-loaded solid lipid nanoparticles (SLNs) to disrupt Staphylococcus aureus biofilms in vitro. We hypothesized that surface-adsorbed DNase I or Tween-80 of SLNs will degrade the biofilm component, extracellular DNA (e-DNA), and extracellular matrix (ECM) of S. aureus biofilms. The SLNs loaded with drug (core) and surface-adsorbed disruptors (Tween-80 or DNase I) to deliver biofilm disruptors first at the site of action, which will help to break down the biofilm, and further drug release from the core will easily penetrate the biofilm and facilitate the killing of bacteria residing in S. aureus biofilms. The SLNs were synthesized by the double emulsion method; the size was 287.3 ± 7.4 nm for blank SLNs and 292.4 ± 2.36 nm for drug-loaded SLNs. The ζ-potential of blank SLNs was -25.6 ± 0.26 mV and that of drug-loaded SLNs was -13.16 ± 0.51 mV, respectively. The successful adsorption of DNase I or Tween-80 was confirmed by the activity of DNase I in blank surface-adsorbed SLNs and the change in the ζ-potential of SLNs after adsorbing DNase I or Tween-80. The surface morphology and size of the SLNs were further characterized using scanning electron microscopy. The encapsulation efficiency of the drug was 16.85 ± 0.84%. The compatibility of the drug with the excipient was confirmed by Fourier transform infrared spectroscopy and the degree of crystallinity was confirmed by X-ray diffraction (XRD) analysis. SLNs showed a sustained release of the drug up to 360 h. SLNs were easily taken up by A549 cells with minimal or no toxicity. The present study showed that Tween-80- or DNase I-adsorbed SLNs efficiently disrupt S. aureus biofilms and possess no or minimal toxicity against cells and red blood cells (RBCs).

The effect of emulsifier type and oil inclusion on stress-related gene expression of Salmonella typhimurium in oil-in-water emulsion.

Salmonella has been associated with numerous outbreaks from contaminated food products, including emulsions. Emulsions are influenced by emulsifier type and oil presence, which can have varying degrees of stress or protection on bacteria. Although our previous research has shown that emulsifier solutions, rather than emulsions, provide a protective effect on Salmonella typhimurium after thermal treatment, the underlying mechanism remains unclear. This study selected S. typhimurium as the model microorganism and utilized the same emulsifiers (Tween 20, Tween 80, Triton X-100) to create emulsifier solutions and emulsions with the same oil fraction (60% (v/v)) to examine their effect on the expression of nine selected genes (rpoE, rpoH, otsB, proV, fadA, fabA, dnaK, ibpA, ompC) associated with stress response. Specifically, the study observed variations in gene expression under normal and thermal stress at 55°C. After 20-h incubation, Triton X-100 emulsion caused an upregulation of stress-related genes, rpoE, otsB, and fabA, suggesting stressful environment. After thermal treatment, S. typhimurium in Triton X-100 solution showed a longer 5-log reduction time with increased proV and decreased fabA and ompC expression, suggesting enhanced thermal protection compared to its emulsion. Conversely, Tween 80 solution increased fabA and ompC expression, indicating greater membrane fluidity and passive diffusion, potentially reducing thermal resistance. However, according to the upregulation of ibpA, this effect was likely mitigated by the overproduction of heat shock proteins. Notably, Triton X-100 environments exhibited the most significant gene expression changes after heat treatment, whereas Tween 80 without oil was the most inhospitable for bacterial survival. These findings inform bacterial responses under various conditions, aiding food safety strategies.

Comparative assessment of emulsifiers for in vitro ruminal gas production and fermentation measurements: Tween 80 is a suitable emulsifier.

Emulsifiers are essential for achieving a homogenous distribution of lipophilic supplements in in vitro rumen fluid incubations. Since emulsifiers can alter rumen fermentation, it is crucial to select one that minimally impacts fermentation parameters to reduce potential biases. This study aimed to evaluate seven emulsifiers' impact on in vitro ruminal fermentation using the Hohenheim Gas Test in order to identify the most inert emulsifier. Rumen fluids were collected from three non-lactating Original Brown-Swiss cannulated cows before morning feeding and incubated for 24 h with a basal diet in triplicates. The emulsifiers tested were ethanol, ethyl acetate, propylene glycol, glycerol, ethylene glycol, soy lecithin, and Tween® 80, each in two dosages (0.5% or 1% v/v). The untreated basal diet served as control. Compared to control, in vitro organic matter digestibility was enhanced by ethyl acetate (by 36.9 and 48.2%), ethylene glycol (by 20.6 and 20.1%), glycerol (by 46.9 and 56.8%) and soy lecithin (by 19.7 and 26.8%) at 0.5 and 1% dosage, respectively. Additionally, the 24-h methane production increased for ethanol (by 41.9 and 46.2%), ethylene glycol (by 50.5 and 51.5%), and glycerol (by 63.1 and 65.4%) for the 0.5 and 1% dosage, respectively, and 0.5% dosage for ethyl acetate (by 31.6%). The acetate molar proportion was 17.2%pt higher for ethyl acetate, and 25.5%pt lower for glycerol at 1% dosage, compared to the control. The propionate concentration was 22.1%pt higher 1% glycerol, and 15.2%pt and 15.1%pt higher for 0.5 and 1% propylene glycol, respectively, compared to the control. In summary, Tween® 80 did not significantly affect in vitro rumen fermentation parameters, making it the most suitable choice for in vitro incubations involving lipophilic substances in rumen fluid. Ethanol may be considered as an alternative emulsifier if methane production is not the variable of interest.

Gastroprotective effect of rhodanine and 2,4-thiazolidinediones scaffolds in rat stomachs by contribution of anti-apoptotic (BCL-2) and tumor suppressor (P53) proteins.

In recent times, the methods used to evaluate gastric ulcer healing worldwide have been based on visual examinations and estimating ulcer dimensions in experimental animals. In this study, the protective effect of rhodanine and 2,4-thiazolidinediones scaffolds compared to esomeprazole was investigated in an ethanol model of stomach ulcers in rats. Pretreatment with experimental treatments or esomeprazole prevented the development of ethanol-induced gastric ulcers. The severity of the lesions and injuries was significantly lower than that of vehicle (10% Tween 80) treated rats. Significant and excellent results were obtained with the compound 6 group, with inhibition percentage and ulcer area values of 97.8% and 12.8 ± 1.1 mm2, respectively. Synthesized compounds 2, 7 and 8 exhibited inhibition percentages and ulcer areas of 94.3% and 31.2 ± 1.1 mm2, 91. 3% and 48.1 ± 0. 8 mm2, 89. 5% and 57. 6 ± 1. 2 mm2, and 89. 1% and 60.3 ± 0. 8 mm2, respectively. These biological outcomes are consistent with the docking studies in which Compounds 7 and 8 showed remarkable binding site affinities toward human H+/K+-ATPase α protein (ID: P20648), rat H+/K+-ATPase α protein (ID: P09626), and Na+/K+-ATPase crystal structure (PDB ID:2ZXE) with binding site energies of - 10.7, - 9.0, and - 10.4 (kcal/mol) and - 8.7, - 8.5, and - 8.0 (kcal/mol), respectively. These results indicate that these test samples were as effective as esomeprazole. Likewise, immunohistochemical staining of antiapoptotic (BCL2) and tumor suppressor (P53) proteins showed strong positive marks in the10% Tween 80- treated group, opposing the mild staining results for the esomeprazole-treated group. Similarly, the staining intensity of the group treated with Compounds 2-8 was variable for both proteins.

Efficacy and safety of geranium-oregano-thymol formulations to control of dog tick Rhipicephalus sanguineus sensu lato under laboratory and field conditions.

The present study evaluated, in laboratory and field, the efficacy and safety of formulations of Pelargonium graveolens (geranium - G), Origanum majorana (oregano - O) commercial essential oils (EO) and thymol (T) to control of Rhipicephalus sanguineus sensu lato. In the laboratory, three formulas (A: 2% tween 80%, B: powder and C: nanoemulsion) by a mixture of these components (GOT) were prepared and evaluated, and the best one was used to assess its safety and field application against R. sanguineus s. l. on naturally infested dogs. Besides the major compounds of the EO used were identified. The results of the lab study showed that formula A (2.5 g of each G + O + T + 2% tween 80 to complete 100 mL) was significantly more effective than the other two formulas tested and exhibited highly effective adulticidal, larvicidal, and ovicidal activity against R. sanguineus s.l. Significant LC50 and LC90 values of GOT were evaluated (13.4 and 21.5 mg/mL, respectively) for the adulticidal activity, (2.81 and 4.46 mg/mL, respectively) for ovicidal activity and (2.44 and 4.45 mg/mL, respectively) for larvicidal activity. The safety of formula A has been proven by the absence of its cytotoxicity on a cell line of human epidermoid carcinoma. Citronella and carvacrol were the major compounds identified in the commercial essential oils of P. graveolens and O. majorana, respectively. Formula A was used in a field control trial for almost 8 months, during the tick infestation season (April to November, 2022). Fourteen naturally infested dogs were divided into two groups, each with seven dogs. One group received formula A spraying five times during an experiment that continued for 8 months, while the other group received treatment with commercially available malathion acaricide. The animals were sprayed on five occasions throughout the experiment (April, June, July, August, and September). The results showed a substantial percentage of effectiveness after the first application of formula A with a 99.3% reduction in tick count at day 28 post-application (PA). In the case of severe infestation 60 days after the first application of formula A (more than 180 ticks per dog), the second application was done, achieving an efficacy of 54.9% at day 3 PA, so an emergency spray was done at day 5 PA to combat the rest of the tick infestation, achieving efficacy of 99% after 3 days. Consequently, a regular spray (third, fourth, and fifth application) was done every 35 days. This regular spray revealed 100% effectiveness at 14 days PA. Biochemical parameters of treated dogs were evaluated to confirm the safety of formula A. Creatinine, ALT, and albumin of the dogs treated with formula A were within the normal range of dogs, while urea and AST were higher than the normal range. In conclusion, formula A can safely treat R. sanguineus s.l. infestations in dogs with regular application every 5 weeks.

Staphylococcus aureus Biofilm Destabilization by Tween-80 and Lung Surfactants to Overcome Biofilm-Imposed Drug Resistance.

This study is aimed to evaluating the potential of tween-80 and artificial lung surfactant (ALS) to destabilize S. aureus biofilm. The biofilm destabilization was studied by crystal violet staining, bright field microscopy, and scanning electron microscopy (SEM). During the study, S. aureus biofilm was exposed with tween-80 along various concentrations (1%, 0.1%, and 0.05%) or LS (lung surfactant) at (2.5%, 5%, and 15%) for 2 hrs. It was observed that 0.1% of tween-80 destabilized 63.83 ± 4.35% and 15% ALS 77 ± 1.7% biofilm in comparison to without treatment. The combination of tween-80 and ALS was used and showed a synergistic effect to destabilize 83.4 ± 1.46% biofilm. These results showed the potential of tween-80 and ALS as biofilm disruptors, which further needs to explore in an in-vivo animal model to access the actual potential of biofilm disruption in natural conditions. This study could play a pivotal role to overcome the problem of antibiotic resistance imposed due to biofilm formation to combat antibiotic resistance imposed by bacteria.

Comparative evaluation of effect of nisin-incorporated ethylenediamine tetraacetic acid and MTAD on endodontic biofilm eradication, smear layer removal, and depth of sealer penetration.

OBJECTIVES: To comparatively evaluate the nisin-incorporated ethylenediamine tetraacetic acid (N-EDTA) and MTAD on cytotoxicity, endodontic biofilm eradication potential, smear layer removal ability, and sealer penetration depth. MATERIALS AND METHODS: N-EDTA was prepared and characterized using high-performance liquid chromatography (HPLC). Minimum inhibitory, minimum bactericidal, and minimum biofilm inhibitory concentration (MBC, MIC, and MBIC) were determined on Enterococcus faecalis (E. faecalis) strain. The cytocompatibility of N-EDTA and MTAD was evaluated using 3,(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-based colorimetric assay. Dentin specimens (n = 88 for antibacterial analysis, n = 170 for sealer penetration depth) were prepared and subjected to the classical irrigating strategy and obturation, respectively. The scanning electron microscopic evaluation (SEM) was done for the evaluation of biofilm disruption and smear layer removal. Confocal laser scanning microscopy (CLSM) evaluation was done for determining percentage of bacterial viability and sealer penetration depth. Statistical analysis of one-way ANOVA and Tukey's HSD post hoc tests for bacterial viability and Kruskal-Wallis test and Mann-Whitney test for smear layer removal and depth of penetration were done with the significance level set at p < 0.05. RESULTS: MTAD and N-EDTA showed cytocompatibility without any statistical differences from each other. For N-EDTA, the MIC and MBC values were 12.5 µg/ml (1:8), and MBIC values were 36 µg/ml. Biofilm disruption and killed bacterial percentage of N-EDTA was statistically higher than MTAD, whereas both the materials showed similar efficacy in the removal of the smear layer and sealer penetration depth. CONCLUSION: N-EDTA had negligible cytotoxicity with similar smear layer removal ability, sealer penetration, and better antibiofilm potential than MTAD. CLINICAL RELEVANCE: N-EDTA can serve as a viable alternative endodontic irrigant.

Polysorbate 80 surface modified SLNs of formoterol suppress SNCA gene and mitochondrial oxidative stress in mice model of Parkinson's disease.

The present study hypothesises that the selective brain ß2 receptor activation through ß2-adrenoreceptor agonist (ß2ARA), Formoterol (FMT), suppresses SNCA gene expression, a pathological hallmark of Parkinson's disease (PD) in brain. Further, it is also hypothesized that brain targeted delivery of Formoterol via polysorbate-80 surface modified solid lipid nanoparticles of Formoterol (FMT-SLNs-PS80) can improve its stability, therapeutic efficacy and avoid/reduce peripheral off-target side effects. FMT-SLNs-PS80 was prepared by solvent injection method, the formulation was optimized by using Box-Behnken design and characterized by measuring drug content, entrapment efficacy, particle size, zeta potentials and poly dispersibility. The FMT-SLNs-PS80, significantly decreases the SNCA expression, mitochondrial membrane damage and rotenone induced changes in oxidative (SOD, CAT, GSH and ROS) stress markers in SH-SY5Y cell lines. The ex vivo permeation study of the formulation using everted chicken ileum exhibited a steady state flux. The pharmacokinetic and tissue distribution studies of the formulation in rats showed a significant improvement in the kinetic parameters when compared to naïve FMT, further the formulation also improved the brain bioavailability of FMT. The anti-Parkinson's efficacy studies of the formulation in mice showed a significant neuroprotection against rotenone-induced changes in behavioural and biochemical parameters. Further, the histopathological analysis of mice brain confirms a significant neuroprotective benefit. The present study successfully establishes the brain targeted delivery and anti-Parkinson's therapeutic efficacy of FMT-SLNs-PS80.

The effect of emulsifier type and oil fraction on Salmonella Typhimurium growth and thermal inactivation in oil-in-water emulsion.

High water activity oil-in-water emulsions can promote survival and growth of Salmonella Typhimurium. Nevertheless, the precise effect of emulsifier type and oil content on bacterial growth and inactivation is not fully understood. Here, emulsions were prepared using different emulsifiers (Tween 20, Tween 80, and Triton X-100) and different oil fractions (20%, 40%, and 60% (v/v)). TSB (control), emulsifier solutions, and emulsions were inoculated with S. Typhimurium. Bacterial growth rate was measured at 7, 22, and 37°C, whereas thermal inactivation was performed at 55°C. Growth and inactivation data was fitted into Logistic and Weibull models, respectively. At an incubation temperature of 37°C, the presence of high amount of oil (60%) in Tween 20 and Triton X stabilized emulsions extended the lag phase (5.83 ± 2.20 and 9.43 ± 1.07 h, respectively, compared to 2.28 ± 1.54 h for TSB, p < 0.05), whereas individual emulsifiers had no effect on growth behavior compared to TSB. This effect was also prevalent but attenuated at 22°C, whereas no growth was observed at 7°C. In thermal inactivation, we observed protective effect in Tween 80 and Triton X-100 solutions, where time required for five-log reduction was 1914.70 ± 706.35 min and 795.34 ± 420.09 min, respectively, compared to 203.89 ± 10.18 min for TSB (p < 0.05). Interestingly, the presence of high amount of oil did not offer protective effect during thermal inactivation. We hypothesize that oleic acid in Tween 80 and lower hydrophobicity value of Triton X-100 help maintain membrane integrity and improve the resistance of bacteria to heat inactivation.

Vaccination against microbiota motility protects mice from the detrimental impact of dietary emulsifier consumption.

Dietary emulsifiers, including carboxymethylcellulose (CMC) and polysorbate 80 (P80), perturb gut microbiota composition and gene expression, resulting in a microbiota with enhanced capacity to activate host pro-inflammatory gene expression and invade the intestine's inner mucus layer. Such microbiota alterations promote intestinal inflammation, which can have a variety of phenotypic consequences including increased adiposity. Bacterial flagellin is a key mediator of emulsifiers' impact in that this molecule enables motility and is itself a pro-inflammatory agonist. Hence, we reasoned that training the adaptive mucosal immune system to exclude microbes that express flagellin might protect against emulsifiers. Investigating this notion found that immunizing mice with flagellin elicited an increase in mucosal anti-flagellin IgA and IgA-coated microbiota that would have otherwise developed in response to CMC and P80 consumption. Yet, eliciting these responses in advance via flagellin immunization prevented CMC/P80-induced increases in microbiota expression of pro-inflammatory agonists including LPS and flagellin. Furthermore, such immunization prevented CMC/P80-induced microbiota encroachment and deleterious pro-inflammatory consequences associated therewith, including colon shortening and increased adiposity. Hence, eliciting mucosal immune responses to pathobiont surface components, including flagellin, may be a means of combatting the array of inflammatory diseases that are promoted by emulsifiers and perhaps other modern microbiota stressors.

Solvents and detergents compatible with enzyme kinetic studies of cholinesterases.

Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are enzymes that serve a wide range of physiological functions including the hydrolysis of the neurotransmitter acetylcholine and several other xenobiotics. The development of inhibitors for these enzymes has been the focus for the treatment of several conditions, such as Alzheimer's disease. Novel chemical entities are evaluated as potential inhibitors of AChE and BChE using enzyme kinetics. A common issue encountered in these studies is low aqueous solubility of the possible inhibitor. Additives such as cosolvents or detergents can be included in these studies improve the aqueous solubility. Typical cosolvents include acetonitrile or dimethyl sulfoxide while typical detergents include Polysorbate 20 (Tween 20) or 3-((3-cholamidopropyl) dimethylammonio)-1-propanesulfonate (CHAPS). When solubility is not improved, these molecules are often not evaluated further. To address this issue eleven cosolvents and six detergents that could facilitate aqueous solubility were evaluated to understand how they would affect cholinesterase enzymes using Ellman's assay. These studies show that propylene glycol, acetonitrile, methanol, Tween 20, Polysorbate 80 (Tween 80), polyoxyethylene 23 lauryl ether (Brij 35) and polyoxyethylene 10 oleoyl ether (Brij 96v) have the least inhibitory effects towards cholinesterase activity. It is concluded that these cosolvents and detergents should be considered as solubilizing agents for evaluation of potential cholinesterase inhibitors with low aqueous solubility.

Comparison of rumen and abomasal infusions of an exogenous emulsifier on fatty acid digestibility of lactating dairy cows.

We evaluated the effects of infusing an exogenous emulsifier (polysorbates-C18:1) either into the rumen or abomasum on fatty acid (FA) digestibility and production responses of lactating dairy cows. Nine ruminally cannulated multiparous Holstein cows (170 ± 13.6 d in milk) were assigned to a treatment sequence in replicated 3 × 3 Latin squares with 18-d periods consisting of 7 d of washout and 11 d of infusion. Treatments were abomasal infusions of water carrier only into the rumen and abomasum (control, CON), 30 g/d polysorbate-C18:1 (T80) infused into the rumen (RUM), or 30 g/d T80 infused into the abomasum (ABO). Emulsifiers were dissolved in water and delivered at 6-h intervals (total daily infusion was divided into 4 equal infusions per day). Cows were fed the same diet that contained [% diet dry matter (DM)] 32.2% neutral detergent fiber (NDF), 16.1% crude protein, 26.5% starch, and 3.41% FA (including 1.96% FA from a saturated FA supplement containing 28.0% C16:0 and 54.6% C18:0). Two orthogonal contrasts were evaluated: (1) the overall effect of T80 {CON vs. average of the T80 infusions [1/2 (ABO + RUM)]}, and (2) the effect of ABO versus RUM infusion. Compared with CON, infusing T80 increased the digestibilities of NDF (2.85 percentage units), total (4.35 percentage units), 16-carbon (3.25 percentage units), and 18-carbon FA (4.60 percentage units), and tended to increase DM digestibility and total and 18-carbon FA absorption. Compared with RUM, ABO decreased the intakes of total (28 g/d), 16-carbon (7 g/d), and 18-carbon FA (19 g/d); tended to increase the digestibility of total and 18-carbon FA; and had no effect on the absorption of total, 16-carbon, or 18-carbon FA. Production responses did not change among our treatments. In conclusion, infusing 30 g/d polysorbates-C18:1 increased NDF and total, 16-carbon, and 18-carbon FA digestibility. Compared with RUM, ABO tended to increase the digestibilities of total and 18-carbon FA; however, this may be related to the fact that ABO reduced the intakes of total, 16-carbon, and 18-carbon FA, not necessarily due to better emulsifying action per se. In summary, ABO and RUM both improved FA absorption.

Regulating effects of phytosterol esters-loaded emulsions stabilized with green tea polysaccharide conjugates and Tween on lipids in KKAy mice.

Phytosterol esters (PSE) have been shown to have cholesterol-lowering effects, but their insolubility in water limits their applications. Green tea polysaccharide conjugates (gTPC) have hypoglycemic and emulsifying effects. To address lipid dysregulation in diabetic patients, we developed PSE-loaded emulsions stabilized with gTPC and Tween-20 (gTPC-PSE emulsions) and evaluated their physicochemical properties. We subsequently investigated the lipid-regulating potential of these emulsions to in KKAy mice. The KKAy mice were randomly assigned to eight groups: the model group, the Lipitor (10 mg·kg-1)-acarbose (30 mg·kg-1) combination group, two gTPC groups, two PSE groups, and two gTPC-PSE groups with a 1:2 mass ratio of gTPC to PSE. The administered doses were 90 and 270 mg kg-1, respectively. Administration of a 270 mg·kg-1 dose of gTPC-PSE emulsions led to the most significant effects including increased levels of liver and serum high-density lipoprotein cholesterol (HDL-CH), reduced serum leptin and insulin, and improved liver superoxide dismutase (SOD) and reduced malondialdehyde (MDA). In general, gTPC and PSE demonstrated a synergistic effect on lipid regulation in mice. Our results indicate that gTPC-PSE emulsions hold potential as a nutritional intervention for diabetes by modulating lipid levels.

Surfactants reduce aggregation of monoclonal antibodies in cell culture medium with improvement in performance of mammalian cell culture.

Therapeutic monoclonal antibodies (mAbs) are biologics produced using mammalian cells and represent an important class of biotherapeutics. Aggregation in mAbs is a major challenge that can be mitigated by rigorous and reproducible upstream and downstream approaches. The impact of frequently used surfactants, like polysorbate 20, polysorbate 80, poloxamer 188, and 2-hydroxypropyl-beta-cyclodextrin, on aggregation of mAbs during cell culture was investigated in this study. Their impact on cell proliferation, viability, and mAb titer was also investigated. Polysorbate 20 and polysorbate 80 at the concentration of 0.01 g/L and poloxamer 188 at the concentration of 5 g/L were found to be effective in reducing aggregate formation in cell culture medium, without affecting the cell growth or viability. Furthermore, their presence in culture media resulted in increased cell proliferation as compared to the control group. Addition of these surfactants at the specified concentrations increased monomer production while decreasing high molecular weight species in the medium. After mAbs were separated, using protein "A" chromatography, flasks with surfactant exhibited improved antibody stability, when analyzed by DLS. Thus, while producing aggregation-prone mAbs via mammalian cell culture, these excipients may be employed as cell culture medium supplements to enhance the quality and yield of functional mAbs.

Nanoemulsions for increased penetrability and sustained release of leishmanicidal compounds.

In the last decade, the World Health Organization has driven the development of drugs for topical use in patients with cutaneous leishmaniasis (CL), the most prevalent clinical form of leishmaniasis, a neglected tropical disease. The chemicals C6 I, TC1, and TC2 were reported as promising antileishmanial drugs. We aimed to develop a topical nanoformulation that enhances the advantageous effect of C6 I, TC1, and TC2, guaranteeing higher stability and bioavailability of the pharmacologically active components through the topical route. Nanoemulsions were prepared by ultrasonication based on oleic acid (0.5 g). A relation of Tween®-80/ethanol (1:3) and water was obtained; physicochemical characterization of all formulations was performed, and the preliminary stability and transdermal penetration of these nanoemulsions were also investigated. Newtonian-type fluids with high load capacity, 147-273 nm globule size, and -15 to -18 mV zeta potential were obtained with differential permeability rates in the first pig ear skin assay, first-order kinetics-release model for C6 I, and Weibull for TC1 and TC2. The nanoemulsion showed good stability, high encapsulation efficiency, and higher leishmanicidal activity against Leishmania braziliensis with lower cytotoxicity in U937 macrophages. In conclusion, nanoemulsions of ethanol-oleic acid/Tween®-80 increase the activity of compounds with leishmanicidal activity by increasing their penetration and sustained release.

Benzonatate as a local anesthetic.

INTRODUCTION: Benzonatate is an FDA-approved antitussive agent that resembles tetracaine, procaine, and cocaine in its chemical structure. Based on structural similarities to known local anesthetics and recent findings of benzonatate exerting local anesthetic-like effects on voltage-gated sodium channels in vitro, we hypothesized that benzonatate will act as a local anesthetic to yield peripheral nerve blockade. METHODS: Benzonatate was injected at the sciatic nerve of Sprague-Dawley rats. Sensory and motor blockade were assessed using a modified hot plate test and a weight-bearing test, respectively. Additionally, the effect of co-injection with tetrodotoxin and Tween 80 (a chemical permeation enhancer) was examined. Myotoxicity of benzonatate was assessed in vivo by histological analysis. RESULTS: Benzonatate produced a concentration-dependent sensory and motor nerve blockade with no appreciable systemic effects. Co-injection with tetrodotoxin or Tween 80 produced prolongation of sensory nerve blockade. Histologic assessment showed significant inflammation and myotoxicity from benzonatate injection, even at low concentrations. CONCLUSION: This study demonstrates that benzonatate does act as a local anesthetic at the peripheral nerve, with sensory and motor nerve blockade. Benzonatate interacts with tetrodotoxin and Tween 80 to prolong nerve blockade. However, benzonatate causes significant myotoxicity, even at subtherapeutic concentrations.