Do mineral and corn oil serve as potential endocrine disruptors in the gerbil prostate?

Vegetable oils are frequently used as a vehicle in the administration of lipophilic drugs in animal tests. However, the composition of these oils may interfere with the results. One alternative to reduce this potential bias is the use of mineral oil, which is not supposed to interfere in the physiology of experimental models, since this oil is considered to be innocous. The present study shows for the first time the effects of the oral administration of corn and mineral on the prostate, demonstrating their interference in homeostasis and revealing their potential to act as endocrine disruptors. Mineral oil treatment increased the expression of AR and ERα and serum estradiol concentrations, while corn oil increased the expression of positive cells for both types of estrogen receptors. The variation in the expression of these hormone receptors resulted in morphological changes in the prostate.

Acute intravenous exposure to silver nanoparticles during pregnancy induces particle size and vehicle dependent changes in vascular tissue contractility in Sprague Dawley rats.

The use of silver nanoparticles (AgNP) raises safety concerns during susceptible life stages such as pregnancy. We hypothesized that acute intravenous exposure to AgNP during late stages of pregnancy will increase vascular tissue contractility, potentially contributing to alterations in fetal growth. Sprague Dawley rats were exposed to a single dose of PVP or Citrate stabilized 20 or 110nm AgNP (700µg/kg). Differential vascular responses and EC50 values were observed in myographic studies in uterine, mesenteric arteries and thoracic aortic segments, 24h post-exposure. Reciprocal responses were observed in aortic and uterine vessels following PVP stabilized AgNP with an increased force of contraction in uterine artery and increased relaxation responses in aorta. Citrate stabilized AgNP exposure increased contractile force in both uterine and aortic vessels. Intravenous AgNP exposure during pregnancy displayed particle size and vehicle dependent moderate changes in vascular tissue contractility, potentially influencing fetal blood supply.

Development of a liquid formulation of poorly water-soluble isosteviol sodium using the co-solvent technology.

An intravenously injectable liquid formulation of the poorly water-soluble isosteviol sodium (ISVNa) that has a great clinical potential for cardiovascular diseases was developed using the co-solvent technology. The pH and composition of the co-solvent were optimized to obtain a stable liquid formulation (termed as STVNa) based on saline at pH 10.0 containing 25% (v/v) of ethanol and 20% (v/v) of propylene glycol. STVNa was physicochemically stable upon storage for more than 3 months under various conditions. In vitro studies showed that STVNa did not induce hemolytic effects up to 9.1% (v/v) after 3 h of incubation and it was cytocompatible up to 50 µg/mL in H2C9 cells. Furthermore, STVNa showed acceptable safety and pharmacokinetic parameters comparable with those of ISVNa in saline (dissolved at 60 °C) upon i.v. injection in Wistar rats. Overall, the results demonstrated that STVNa is a promising formulation of ISVNa for clinical translation.

Estudio del efecto de grandes volúmenes de nanopartículas de quitosano sobre diferentes órganos murinos, al ser administradas diariamente durante dos semanas / Study of the effect of large volumes of chitosan on different murine organs, to be administered daily for two weeks

Objetivo. Las nanopartículas de quitosano han sido usadas recientemente en diversas formulaciones farmacéuticas, este trabajo evaluó la toxicidad que pueden presentar estas estructuras. Material y Métodos. Se utilizaron ratones de la cepa BALB/c administrados durante 15 días con nanopartículas de manera intraperitoneal posterior a lo cual se sacrificaron, obtuvieron diversos órganos y trataron para su análisis. Resultados: Los resultados muestran que las nanopartículas de quitosano presentan toxicidad en ratones machos, ya que pueden dañar corazón, intestino, riñón, bazo e hígado. Conclusión: La exposición a nanopartículas de quitosano causó daño histológico sobre corazón, hígado, bazo, intestinos y riñón

Aim: Chitosan nanoparticles have been use on different pharmaceutical formulations, however there is not data important that show if these structures are toxic. In this work we studied the acute toxicity of chitosan nanoparticles. Methods: We used mice BALB/c, the chitosan nanoparticles was administrated intraperitoneal via by 15 day after these, the mice was sacrifice by cervical dislocation and the organs were treated for histological analysis using HE stain. Results: The histological results showed that chitosan nanoparticles causes damage on heart, liver, spleen, intestine and kidney in mouse BALB/c male. Conclusion: The exposure at chitosan nanoparticles causes histological damage on heart, liver, spleen, intestine and kidney

Nanosuspension formulations of poorly water-soluble compounds for intravenous administration in exploratory toxicity studies: in vitro and in vivo evaluation.

This study was conducted to investigate the use of a nanosuspension for intravenous injection into dogs to increase exposure without toxic additives for preclinical studies in the discovery stage. Nanosuspensions were prepared with a mixer mill and zirconia beads with a vehicle of 2% (w/v) poloxamer 338, which was confirmed to lead to no histamine release in dogs. Sterilized nanosuspensions of poorly water-soluble compounds, cilostazol (Cil), spironolactone (Spi) and probucol (Pro), at 10 mg ml(-1) were obtained by milling for 30 min, followed by autoclaving for 20 min at 121 °C and milling for 30 min (mill-autoclave-mill method). The particle sizes (d50) of Cil, Spi and Pro were 0.554, 0.484 and 0.377 µm, respectively, and the percentages of the nominal concentration were 79.1%, 99.6% and 75.4%, respectively. In chromatographic data, no extra peaks were observed. The particle size of Cil was 0.564 µm after storage for 16 days at 2-8 °C. Cil in nanosuspension, but not in microsuspension, rapidly dissolved in dog plasma. Cil nanosuspension at 0.4 mg kg(-1) and Cil saline solution at 0.03 mg kg(-1) , around the saturation solubility, were intravenously administered to dogs. Nanosuspension increased exposure. The versatility of the mill-autoclave-mill method was checked for 15 compounds, and the particle size of 12 compounds was in the nano range. The nanosuspension optimized in this study may be useful for intravenous toxicological and pharmacological studies in the early stage of drug development. Copyright © 2016 John Wiley & Sons, Ltd.

Gelucire and Gelucire-PEG400 formulations; tolerability in species used for non-clinical safety testing after oral (gavage) dosing.

The selection of a vehicle for oral formulations of compounds to be used in non-clinical safety studies is a challenge for poorly soluble compounds. Typically a compromise between solubility and tolerability has to be reached. Vehicle tolerability data are not readily available for a number of vehicles, and a series of oral tolerability studies were, therefore, conducted with Gelucire and Gelucire:PEG400 formulations in rats, dogs and minipigs in order to determine tolerable daily dose volumes in these species. Gelucire and Gelucire:PEG400 formulations were assessed in studies for up to 5 days in minipigs, 7 days in rats and up to 39 weeks in dogs. Gastrointestinal side effects in terms of soft and/or liquid faeces were noted in all species, but the sensitivity to these effects differed between species with the dog being the most sensitive. It was concluded that Gelucire:PEG400 (90:10) was tolerated in Beagle dogs when administered at 1 ml kg(-1) once daily for 39 weeks, and 100% Gelucire was tolerated in the rat and the minipig when administered once daily at 5 ml kg(-1) for 5 days. Copyright © 2016 John Wiley & Sons, Ltd.

Effect of borneol on the transdermal permeation of drugs with differing lipophilicity and molecular organization of stratum corneum lipids.

The aim of the present paper was to investigate the promoting activity of borneol on the transdermal permeation of drugs with differing lipophilicity, and probe its alterations in molecular organization of stratum corneum (SC) lipids. The toxicity of borneol was evaluated in epidermal keratinocyte HaCaT and dermal fibroblast CCC-HSF-1 cell cultures and compared to known enhancers, and its irritant profile was also assessed by transepidermal water loss (TEWL) evaluation. The promoting effect of borneol on the transdermal permeation of five model drugs, namely 5-fluorouracil, antipyrine, aspirin, salicylic acid and ibuprofen, which were selected based on their lipophilicity denoted by logp value, were performed using in vitro skin permeation studies. Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) was employed to monitor the borneol-induced alteration in molecular organization of SC lipids. The enhancer borneol displayed lower cytotoxicity or irritation in comparison to the well-established and standard enhancer Azone. Borneol could effectively promote the transdermal permeation of five model drugs, and its enhancement ratios were found to be parabolic curve with the logp values of drugs, which exhibited the optimum permeation activity for relatively hydrophilic drugs (an estimated logp value of -0.5 ∼0.5). The molecular mechanism studies suggested that borneol could perturb the structure of SC lipid alkyl chains, and extract part of SC lipids, resulting in the alteration in the skin permeability barrier.

Safety data on 19 vehicles for use in 1 month oral rodent pre-clinical studies: administration of hydroxypropyl-ß-cyclodextrin causes renal toxicity.

Potential new drugs are assessed in pre-clinical in vivo studies to determine their safety profiles. The drugs are formulated in vehicles suitable for the route of administration and the physicochemical properties of the drug, aiming to achieve optimal exposure in the test species. The availability of safety data on vehicles is often limited (incomplete data, access restricted/private databases). Nineteen potentially useful vehicles that contained new and/or increased concentrations of excipients and for which little safety data have been published were tested. Vehicles were dosed orally once daily to HanWistar rats for a minimum of 28 days and a wide range of toxicological parameters were assessed. Only 30% (w/v) hydroxypropyl-ß-cyclodextrin was found unsuitable owing to effects on liver enzymes (AST, ALT and GLDH), urinary volume and the kidneys (tubular vacuolation and tubular pigment). 20% (v/v) oleic acid caused increased salivation and hence this vehicle should be used with caution. As 40% (v/v) tetraethylene glycol affected urinary parameters, its use should be carefully considered, particularly for compounds suspected to impact the renal system and studies longer than 1 month. There were no toxicologically significant findings with 10% (v/v) dimethyl sulphoxide, 20% (v/v) propylene glycol, 33% (v/v) Miglyol®812, 20% (w/v) Kolliphor®RH40, 10% (w/v) Poloxamer 407, 5% (w/v) polyvinylpyrrolidone K30 or 10% (v/v) Labrafil®M1944. All other vehicles tested caused isolated or low magnitude effects which would not prevent their use. The aim of sharing these data, including adverse findings, is to provide meaningful information for vehicle selection, thereby avoiding repetition of animal experimentation.

Oral toxicity of Miglyol 812(®) in the Göttingen(®) minipig.

Miglyol 812(®), a mixture of medium-chain triglycerides, has been identified as an oral vehicle that could improve the solubility and possibly the bioavailability of orally administered drugs during the non-clinical safety assessment. The toxicity of Miglyol was assessed in Göttingen(®) minipigs upon daily oral administration (gavage) for six weeks, at dosing-volumes of 0.5 and 2 mL/kg/day, compared to controls receiving 0.5% CarboxyMethylCellulose/0.1% Tween(®) 80 in water at 2 mL/kg/day. The control vehicle did not induce any findings. Miglyol at 0.5 and 2 mL/kg/day induced transient tremors, abnormal color of feces and increase in triglycerides. Miglyol at 2 ml/kg/day also induced reduced motor activity, decreased food intake, respiratory signs (2/6 animals) and increased total and LDL-cholesterol. At necropsy, the lung of 3/6 animals treated at 2 mL/kg/day presented abnormal color and/or irregular surface correlated with a chronic bronchiolo-alveolar inflammation. This finding is probably due to aspiration pneumonia in relation to the administration method and the high viscosity of Miglyol. Overall, the oral administration of pure Miglyol 812(®) for six weeks up to 2 mL/kg was less tolerated than that of the control vehicle. Miglyol as vehicle for sub-chronic oral toxicity studies in minipigs should be used with a limited dosing-volume.

A permeation enhancer for increasing transport of therapeutic macromolecules across the intestine.

Delivery of therapeutic macromolecules is limited by the physiological limitations of the gastrointestinal tract including poor intestinal permeability, low pH and enzymatic activity. Several permeation enhancers have been proposed to enhance intestinal permeability of macromolecules; however their utility is often hindered by toxicity and limited potency. Here, we report on a novel permeation enhancer, Dimethyl palmitoyl ammonio propanesulfonate (PPS), with excellent enhancement potential and minimal toxicity. PPS was tested for dose- and time-dependent cytotoxicity, delivery of two model fluorescent molecules, sulforhodamine-B and FITC-insulin in vitro, and absorption enhancement of salmon calcitonin (sCT) in vivo. Caco-2 studies revealed that PPS is an effective enhancer of macromolecular transport while being minimally toxic. TEER measurements in Caco-2 monolayers confirmed the reversibility of the effect of PPS. Confocal microscopy studies revealed that molecules permeate via both paracellular and transcellular pathways in the presence of PPS. In vivo studies in rats showed that PPS enhanced relative bioavailability of sCT by 45-fold after intestinal administration. Histological studies showed that PPS does not induce damage to the intestine. PPS is an excellent permeation enhancer which provides new opportunities for developing efficacious oral/intestinal delivery systems for therapeutic macromolecules.

Formulation and cytotoxicity evaluation of new self-emulsifying multiple W/O/W nanoemulsions.

Three multiple water-in-oil-in-water (W/O/W) nanoemulsions have been designed for potential inclusion of either lipophilic or hydrophilic drugs using a two-step emulsification process exclusively based on low-energy self-emulsification. The W/O primary emulsion was constituted by a blend of oil (medium chain triglyceride), a mixture (7:3) of two surfactants, and a 10% water phase. The surfactants were a mixture of Polysorbate-85/Labrasol(®), Polysorbate-85/Cremophor(®) EL or glycerol/Polysorbate-85. The final W/O/W nanoemulsions were obtained by the addition of water, with a weight ratio nanoemulsion/water of 1:2. The multiple emulsion stability was found to increase from 24 hours to 2 and 6 months with Labrasol, glycerol, and Cremophor, respectively. Cytotoxicity was found for formulations including Labrasol and Cremophor EL. The concentration of emulsion inhibiting 50% cell viability (IC(50)) was determined using the alamarBlue(®) test, giving after 24 hours of incubation, IC(50) = 10.2 mg/mL for the Labrasol formulation and IC(50) = 11.8 mg/mL for the Cremophor EL formulation. Corresponding calculated IC(50) values for surfactants were 0.51 mg/mL for Labrasol and 0.59 mg/mL for Cremophor EL. In both cases, cytotoxicity was due to an apoptotic mechanism, evidenced by chromatin condensation and P2X7 cell death receptor activation. The formulation including glycerol, investigated between 1 and 100 mg/mL concentration of nanoemulsion, did not affect cell viability. Moreover, neither chromatin condensation nor P2X7 activation was found between the 10 and 30 mg/mL final concentration of the emulsion. This last formulation would therefore be of major interest for further developments.

Comparing the enhancement efficiency between liposomes and microbubbles for insulin pulmonary absorption.

BACKGROUND: The present study investigated the enhancement efficiency between liposomes and microbubbles for insulin pulmonary absorption. METHODS: Two types of phospholipid-based vesicle-liposomes and microbubbles-were prepared, and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) cytotoxicity test was used to evaluate their in vitro toxicity in A549 cells. Cellular uptake of insulin combined with liposomes or microbubbles was determined using A549 cells. With intratracheal insufflation of Sprague-Dawley rats, an insulin mixture with liposomes or microbubbles was administered to assess its potential for promoting drug pulmonary absorption. RESULTS: Both liposomes and microbubbles had a narrow and monodispersed size distribution with average diameter of 3.1 µm and 1.0 µm, respectively. From the MTT cytotoxicity test, a phospholipid-based vesicle concentration of <25% (vol/vol) in the final volume was the safe dosage range that could avoid severe cytotoxic effects. The intracellular uptake amount of insulin in the insulin-microbubble mixture was significantly higher than that in the insulin-liposome mixture. The minimum reductions of the blood glucose concentration produced by insulin-microbubble and insulin-liposome mixtures were 60.8% and 35.0% of the initial glucose levels, respectively, and their bioavailabilities relative to subcutaneous injection were 48.6% and 30.8%, respectively. CONCLUSIONS: Microbubbles have much better efficiency than liposomes in the rate and extent of insulin pulmonary absorption. Microbubbles might be recommended as a potential agent for enhancing protein intrapulmonary absorption.

Diethylene glycol in health products sold over-the-counter and imported from Asian countries.

Diethylene glycol (DEG), a chemical that has been implicated in multiple medication-associated mass poisonings, can result in renal and neurological toxicity if ingested. Three previous such mass poisonings implicated Chinese manufacturers as the origin of contaminated ingredients. No literature exists on potential DEG or triethylene glycol (TEG), a related compound, contamination of health products imported from Asian countries to the USA. Our primary objective was to quantitatively assess the amount of DEG present in a convenience sampling of these health products. The study's secondary objectives were to: (1) evaluate for, and quantify TEG levels in these samples; (2) compare DEG and TEG levels in these products directly to levels in medications implicated in previous similar mass poisonings; and (3) to estimate DEG dose (in mg/kg) based on the manufacturer's instructions and compare these values to toxic doses from past mass poisonings and the literature. A quantitative assessment of DEG and TEG was performed in a convenience sampling of over-the-counter health products imported from Asian countries. Results were converted to volume to volume (v/v) % and compared with DEG levels in medications implicated in previous mass poisonings. Estimated doses (based on the manufacturer's instructions) of each product with detectable levels of DEG for a 70 kg adult were compared to toxic doses of DEG reported in the literature. Seventeen of 85 (20%) samples were not able to be analyzed for DEG or TEG due to technical reasons. Fifteen of 68 (22%) samples successfully tested had detectable levels of DEG (mean, 18.8 µg/ml; range, 0.791-110.1 µg/ml; and volume to volume (v/v) range, 0.00007-0.01%). Two of 68 (3%) samples had TEG levels of 12.8 and 20.2 µg/ml or 0.0012% and 0.0018% TEG v/v. The product with the highest DEG% by v/v was 810 times less than the product involved in the Panama DEG mass poisoning (8.1%). The lowest reported toxic dose from a past DEG mass poisoning (14 mg/kg) was more than 150 times higher than the highest daily dose estimated in our study (0.09 mg/kg). Sixty-eight of 85 (80%) samples were able to be successfully analyzed for DEG and TEG. DEG and TEG were detectable in 15/68 (22%) and 2/68 (3%) samples, respectively. Based on current standards, these levels probably do not represent an acute public health threat. Additional research focusing on why DEG is found in these products and on the minimum amount of DEG needed to result in toxicity is needed.

Assessment of hydroxypropyl methylcellulose, propylene glycol, polysorbate 80, and hydroxypropyl-ß-cyclodextrin for use in developmental and reproductive toxicology studies.

BACKGROUND: A series of studies were conducted to assess Polysorbate 80 (PS80), Propylene Glycol (PG), and Hydroxypropyl-ß-Cyclodextrin (HPßCD), when compared with Hydroxypropyl Methylcellulose (MC) in developmental and reproductive toxicology (DART) studies. METHODS: In the rat fertility study, 20 mg/kg MC, 10 mg/kg PS80, 1,000 mg/kg PG, 500 mg/kg HPßCD or 1,000 mg/kg HPßCD were administered orally before/during mating, and on gestation Day (GD) 0-7, followed by an assessment of embryonic development on GD 14. In the rat and rabbit teratology studies, the doses of MC, PS80, PG, and HPßCD were the same as those in the fertility study. In these teratology studies, pregnant females were dosed during the period of organogenesis, followed by an assessment of fetal external, visceral, and skeletal development. RESULTS: In the rat fertility and rat teratology studies, PS80, PG, and HPßCD did not exhibit toxicity, when compared with MC. Similarly, in the rabbit teratology study, there was no PS80 or PG-related toxicity, when compared with MC. However, individual rabbits in the 500 and 1,000 mg/kg HPßCD groups exhibited maternal toxicity, which included stool findings, decreased food consumption, and body weight gain. Furthermore, one rabbit each in the 500 and 1,000 mg/kg HPßCD groups exhibited evidence of abortion, which was considered secondary to maternal toxicity. CONCLUSIONS: Although HPßCD was not well tolerated in rabbits at doses of 500 and 1,000 mg/kg, PS80 and PG were comparable to MC and should be considered for use in developmental and reproductive toxicology studies.

Comprehensive investigation of hydroxypropyl methylcellulose, propylene glycol, polysorbate 80, and hydroxypropyl-beta-cyclodextrin for use in general toxicology studies.

This study was conducted to assess the safety and tolerability of the alternative formulation vehicles polysorbate 80 (PS80), propylene glycol (PG), and hydroxypropyl-beta-cyclodextrin (HPßCD) in general toxicology studies in the mouse, rat, dog, and monkey. Twenty (20) mg/kg of hydroxypropyl methylcellulose (MC, control), 10 mg/kg PS80, 1000 mg/kg PG, 500 mg/kg HPßCD, or 1000 mg/kg HPßCD were administered by oral gavage to mice, rats, dogs, and cynomolgus monkeys for approximately 90 days. The effects of these formulations on clinical observations, body weight and food consumption parameters, clinical pathology, and histopathology were evaluated across all species. The suitability of formulations containing up to 20 mg/kg MC, 10 mg/kg PS80, and 1000 mg/kg PG for use in preclinical safety studies was confirmed by a lack of effects on all parameters examined. However, formulations containing HPßCD produced elevated transaminase (aspartate and alanine aminotransferase) levels in rats and mice and fecal changes (loose and soft stool) in large animals. Although the etiology and toxicological significance of the transaminase elevations in rats and mice is uncertain, this finding could represent a significant liability for a preclinical formulation because of the critical importance of these biomarkers in the risk assessment of novel therapeutic agents. Based on these data, PS80 and PG are considered to be practical alternatives to MC in preclinical toxicology studies. However, formulations containing HPßCD should be used with caution because of the elevations in rodent transaminase levels.

A new sol-gel silica nanovehicle preparation for photodynamic therapy in vitro.

We report a facile silica nanovehicle preparation procedure for hydrophobic drug delivery, which is carried out in water without adding any surfactant and additional catalyst. This strategy includes hydrophobic drug nanopaticle preparation by reprecipitation method and in situ hydrolyzation and polymerization to encapsulate this naoparticle using only N-(beta-amimoethyl)-gamma-aminopropyltriethoxysilane (AETPS). To demonstrate this technique hypocrellin A (HA), a hydrophobic photosensitizing anticancer drug, is embedded into silica nanovehicle using this simple method. The resulting HA encapsulated nanovehicles (HANV) are monodisperse and stable in aqueous solution. Comparative studies with free HA and entrapped HA have demonstrated that the encapsulation effect on the embedded photosensitizer nanoparticle significantly enhances the efficacy of singlet oxygen generation and, thereby, the in vitro photodynamic efficacy.

Accidental induced seizures in three cynomologus macaques following administration of ceftriaxone dissolved in 1% lidocaine diluent.

Following initial signs of dural infection, or as prophylactic postoperative therapy, three cynomologus macaques were given an intramuscular or a subcutaneous injection of ceftriaxone dissolved in a 1% lidocaine diluent (CL). Two to 15 min later, all three monkeys experienced a long-lasting generalized apnoeic clonic convulsive seizure. The injected doses of lidocaine (0.7-2 mg/kg) were as low as 7-20-fold less than the experimental intravenous dosage (14.2 +/- 3.2 mg/kg) previously reported to induce seizure in healthy rhesus monkeys. Under different clinical conditions, the same three animals were either once (1 animal) or repeatedly given CL without any resultant neurological alterations. The monkeys had a cranial device implanted and two of them were craniotomized. This first report of accidental lidocaine-induced seizure in laboratory non-human primates following CL injection strongly suggests increased susceptibility when lidocaine administration is associated with central nervous system alteration. A novel hypothesis, the possible role of cytokine in lowering the lidocaine seizure threshold, is suggested.

Vehicle used for triamcinolone acetonide is toxic to ocular tissues of the pigmented rabbit.

PURPOSE: To investigate the potential toxicity of the vehicle used for triamcinolone acetonide (TA) to the cornea, lens, ciliary body, and retina of pigmented rabbits. METHODS: Forty chinchilla rabbits (40 eyes) were divided into four groups: group A (control group) eyes received an intravitreal injection of 0.1 ml sterile saline solution; group B eyes received 0.1 ml (1.3 mg) TA plus vehicle; group C eyes received 0.1 ml (1.3 mg) TA alone (vehicle eliminated); group D eyes received 0.1 ml vehicle only. Intraocular pressure (IOP) was measured pre-injection and at 1, 7, 14, 30, and 90 days post-injection. Scotopic and photopic electroretinograms (ERG) were examined pre-injection and 7, 30, and 90 days post-injection. Animals were sacrificed 7, 30, and 90 days post-injection. Eyes were enucleated and examined by light microscopy (LM) and electron microscopy (EM). RESULTS: The IOP of groups B and C was higher than that of other groups on days 1, 7, and 14 post-injection (p < 0.05). ERG amplitudes of groups B and D were lower than those of other groups on days 7 and 30 post-injection (p < 0.05). Histopathological sections indicated morphologic changes in the ciliary body, lens, and retina of eyes in groups B and D. CONCLUSIONS: Vehicle used for TA is toxic to the lens, ciliary body, and retina of pigmented rabbit eyes after injection of intravitreal TA.

Cytotoxicity of solubilization vehicles for Trichomonas gallinae and Tritrichomonas foetus measured by the resazurin microtiter assay.

The parasites Tritrichomonas foetus and Trichomonas gallinae present veterinary and economic importance since they cause bovine and avian trichomonosis, respectively. The absence of a specific treatment and the necessity of effective and safe drugs against these etiologic agents have stimulated the search for new antiprotozoal drugs with high activity, low toxicity to the animal, and low cost. Screening of potential antiprotozoal molecules is currently a common practice and different kinds of organic solvents and surfactant vehicles are used, since many bioactive compounds have low water solubility. Thus, it is important to determine the toxicity and to provide the minimal inhibitory concentration (MIC) values of the most common solubilization vehicles used in biological activity in vitro evaluation: ethanol, methanol, isopropanol, acetone, DMSO, tween 20 and tween 80. The assays were conducted employing the resazurin microtiter assay, which demonstrated a rapid, safe, and quantitative method for the in vitro determination of T. foetus and T. gallinae trophozoites viability. In summary, all solvents and surfactants, except ethanol, could be used in cytotoxicity assays against T. foetus, and acetone, tween 20 and tween 80 are the preferential vehicles for in vitro analysis of potential bioactive compounds against T. gallinae, though these must be used with caution.