A novel ophthalmic latanoprost 0.005% nanoemulsion: a cytotoxicity study.

BACKGROUND: Benzalkonium chloride (BAK), the most commonly used preservative in anti-glaucoma eye drops, inflicts damage to the ocular surface. A novel anti-glaucoma formulation that avoids the use of BAK has been developed. The aim of this study was to evaluate the cytotoxicity of this formulation and to compare it with an ophthalmic solution containing BAK. METHODS: Two different latanoprost eye drops were used: one ophthalmic solution (LSc) containing BAK 0.02% and one ophthalmic nanoemulsion (LNe) with a soft preservative (potassium sorbate 0.18%). Human epithelial conjunctival cells were incubated for 15, 30, and 60 min with either LSc or LNe. The cytotoxicity was determined by MTT assay. Cell death was measured by flow cytometry using annexin V-FITC and propidium iodide. RESULTS: The values of cell viability and proliferation obtained from cells exposed to LNe were between 80 and 90% relative to the control group, whereas values obtained from cells exposed to LSc were around 30% at all study times (p < 0.05 at 15 and 30 min; p < 0.01 at 60 min). The percentage of viable cells decreased significantly when cells were incubated with LSc compared with cells incubated with LNe at all the study times, while the percentage of cells in late apoptosis/necrosis increased significantly in cells exposed to LSc compared to LNe. CONCLUSIONS: The new latanoprost nanoemulsion is significantly less cytotoxic on human conjunctival cells than LSc. These results suggest that the new formulation might be gentler on the eye surface than currently available BAK-preserved latanoprost solutions.

Propylparaben concentrations in the urine of women and adverse effects on ovarian function in mice in vivo and ovarian cells in vitro.

Female reproduction is precisely regulated by hormones, and the ovary is easily affected by environmental endocrine disruptors (EDCs), which are ubiquitous in industrialized societies. Parabens are EDCs that are used as antibacterial preservatives in cosmetics, personal care products (PCPs), medicines, and food. We used ultrahigh-performance liquid chromatography-mass spectrometry to quantitatively detect methyl-, ethyl-, butyl-, and propylparaben (PP) concentrations in urine samples from 74 women of childbearing age. Balb/c mice were subcutaneously injected with 100 mg/kg/day of PP for 21 consecutive days or 100 or 1,000 mg/kg/day of PP during superovulation. Various concentrations of PP (ranging from 1 to 1,000 nM) were added to a human ovarian granulosa tumor-derived cell line (KGN) culture for 24 h. The urinary paraben concentrations of women who used cosmetics and other PCPs within 48 h prior to sample collection were significantly elevated, and the PP concentration was significantly positively correlated with the basal estradiol concentration. After PP injection, the mouse serum estradiol concentrations were significantly increased, estrus cycles were disordered, corpus luteum number was reduced, and number of oocytes retrieved was significantly reduced. In in vitro experiments, PP treatment increased estradiol synthesis and the expression levels of aromatase enzyme (CYP19A1) and steroidogenic acute regulatory protein. This study demonstrates the adverse effects of PP on ovarian estradiol secretion and ovulation, further evaluates the safety of PP as a preservative, and provides guidance for the use of PCPs and cosmetics by women of childbearing age.

Paraben concentrations in human fingernail and its association with personal care product use.

Parabens are used as antimicrobial preservatives in a range of consumer products. However, very limited information is available about the association between use of personal care products and paraben burden in human tissues. Accumulation of parabens in some non-destructive biomarkers (such as human fingernail) is essential for paraben biomonitoring. In this study, 50 human fingernail samples were collected from Nanjing, China. A subset of participants (n = 32) also provided their face cream samples (as the representative of personal care products). Six parabens, including methyl- (MeP), ethyl- (EtP), propyl- (PrP), butyl- (BuP), heptyl- (HeP), and benzyl-parabens (BzP), together with their major metabolites were measured in the fingernail and face cream samples. Total concentrations of parabens and their major metabolites were 39.9-27400 ng/g in fingernails. MeP, PrP and EtP were the three dominant parabens in fingernails with median values of 3140, 1290, and 127 ng/g, respectively. Significantly higher levels in female fingernails than those in male fingernails were observed for MeP, PrP, EtP, BuP, and the MeP metabolite (methyl protocatechuate, OH-MeP) (p < 0.05). Adult fingernails contained greater concentrations of MeP and PrP than juvenile fingernails (p < 0.05). Positive correlations were observed for EtP (R = 0.36, p < 0.05) and BuP (R = 0.48, p = 0.008) concentrations between the fingernail and face cream samples. Our work is a preliminary study trying to explore the quantitative relationship between paraben concentrations in human body and use of personal care products. The result here provides a direct evidence that use of personal care products is one of the major sources for human exposure to parabens.

Urinary Concentrations of Parabens in a Population of Iranian Adolescent and Their Association with Sociodemographic Indicators.

Parabens are widely used as preservatives in personal care products, foodstuffs, and pharmaceuticals. Concerns have been raised regarding the potential endocrine disruption effects of parabens. In the present study, the urinary concentration of four common parabens, including methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP), in 100 Iranian adolescents randomly referring to health services centres were analyzed using GC/MS. The association of sociodemographic and lifestyle variables, collected through questionnaire, with the concentration of parabens also were studied. Median concentrations of MP, EP, PP, and BP were 92.21, 8.46, 12.26, and 8.42 µg/g creatinine, respectively. There was a strong positive significant correlation between MP and PP (r = 0.694) and moderate to a weak correlation between the other parabens. The concentration of urinary MP in females was significantly higher than those in male (p = 0.021). There was a significant negative association between different BMI groups and MP and EP. There also was a positive significant association between the MP and age, and between MP, EP, and PP, and tobacco use. Although the estimated daily intake of the parabens was lower than the Acceptable Daily Intake, it was higher than those reported in other countries. This confirms the widespread exposure of Iranian adolescents to the paraben compounds and their association with sociodemographic factors. This was the first study reporting the urinary parabens level in Iranian adolescents, and the data can be used as a basis for assessing the risk of exposure to parabens in the Iranian population in future studies.

Parameters of ovarian reserve in relation to urinary concentrations of parabens.

BACKGROUND: Parabens are synthetic chemicals commonly used in cosmetics, pharmaceuticals, food and beverage processing as antimicrobial preservatives. In experimental animals, parabens exposure was associated with adverse effects on female reproduction. Despite the widespread use of parabens little is known about their effect on female fecundity. The objective of the current analysis was to evaluate the associations of urinary parabens concentrations with parameters of ovarian reserve among women undergoing treatment in a fertility clinic. METHODS: Five hundred eleven female aged 25-39 years who attended the infertility clinic in central region of Poland for diagnostic purposes were recruited between September 2014 and February 2019. Urinary concentrations of parabens were measured by a validated gas chromatograohy ion-tap mass spectrometry method. Parameters of ovarian reserve were: antral follicle count (AFC), anti-Müllerian hormone (AMH), follicle-stimulating hormone (FSH) and estradiol (E2) levels. RESULTS: The geometric mean of specific gravity adjusted urinary concentrations of methyl (MP), ethyl (EP), propyl (PP), butyl (BP) and izobutyl paraben (iBuP) were 107.93 µg/L, 12.9 µg/L, 18.67 µg/L, 5.02 µg/L and 2.80 µg/L. Urinary concentrations of PP in the third quartile of exposure ((50-75] percentyl) were inversely associated with antral follicle count (p = 0.048), estradiol level (p = 0.03) and positively with FSH concentration (p = 0.026). MP, EP, BP and iBuP parabens were not associated any with parameters of ovarian reserve. CONCLUSIONS: Chronic exposure to PP may potentially contributing to reduced fecundity and impair fertility. As this is one of the first study to investigate the potential effect of parabens on ovarian reserve further epidemiological studies with longer duration of observation are needed.

Urinary parabens in adults from South China: Implications for human exposure and health risks.

Parabens are a kind of preservatives widely used in cosmetic and personal care products and ubiquitously detected in the environment. However, little is known on human exposure to these chemicals. Our study mainly investigated the urinary parabens in adults from South China to evaluate the cumulative risk of paraben exposure. A total of 562 urine samples were collected from adult workers for the determination of methyl paraben (MeP), ethyl paraben (EtP), propyl paraben (PrP), butyl paraben, and benzyl parabens. High detection frequencies (≥98%) were observed for MeP, EtP, and PrP with median concentrations of 8.88, 5.11, and 1.44 µg/L, respectively. Urinary parabens was 4.5-46.2 fold higher in urine of females than those in males. Urinary MeP was associated with alcohol drinking and a history of tumor, while urinary PrP was negatively associated with education levels of the subjects. There were not significant associations between urinary concentrations of parabens and body mass index, which indicated that obesity was not associated with paraben exposure. Also, parabens did not correlate with human dietary habits. Although the total estimated daily intake (TEDI) of the major compound MeP and EtP in adult workers was lower than the acceptable daily intake (ADI), the TEDI of PrP exceed the ADI for a very few subjects, especially for females and low-educated ones, suggesting potential health risks.

FPSE-HPLC-PDA analysis of seven paraben residues in human whole blood, plasma, and urine.

This work describes a new, fast and sensitive method for the simultaneous determination of seven paraben residues including methyl paraben (MPB), ethyl paraben (EPB), propyl paraben (PPB), isopropyl paraben (iPPB), butyl paraben (BPB), isobutyl paraben (iBPB) and benzyl paraben (BzPB) in human whole blood, plasma and urine. The analytes were extracted from the biological matrices by an innovative technique, fabric phase sorptive extraction (FPSE) and subsequently analyzed by high-performance liquid chromatography (HPLC) coupled with photo diode array detector (PDA). The separation was carried out with a Spherisorb C18 column using methanol and phosphate buffer as mobile phases. Ketoprofen was used as the internal standard (IS). The analytical method has been validated according to the International Guidelines in terms of calibration curves for each biological matrix, precision (intra and inter day), trueness, selectivity, LODs, LOQs and ruggedness. Subsequently, the performance of the analytical method was evaluated on real biological samples. The proposed innovative method allows simultaneous analysis of seven paraben residues in three different biological matrices, including whole blood, plasma and urine and therefore it is easily applicable to monitor these substances in different biological samples. Furthermore, extraction technique used in this work is fast, easy to use and in accordance with the modern green analytical chemistry (GAC) principles.

Parabens.

Parabens have been widely used as preservatives in the cosmetics, food, and pharmaceutical industries for more than 70 years. Monitoring for paraben allergy closely followed with studies reporting paraben testing in standard screening fashion as early as 1940. The frequency of sensitivity to this widely used biocide has remained low and remarkably stable for many decades despite extensive use and progressive expansion of utilization worldwide. The authors select paraben mix as the (non)allergen of the year. Paraben reactions are quite uncommon and generally relevant. Parabens remain one of the least allergenic preservatives available. The unsubstantiated public perception of paraben safety has led to its replacement in many products with preservatives having far greater allergenic potential. This report reviews the well-established safety of parabens from an allergologic standpoint.

Parabens and their relation to obesity.

Parabens are a group of chemicals used as preservatives in the food, cosmetic and pharmaceutical industries. They are known to possess estrogenic effects, and therefore have been classified as endocrine disruptors. In addition to the classical endocrine organs, other tissues have endocrine activity, including adipose tissue. Several chemicals are known to cause obesogenic effects, and parabens are currently being studied in this context. The aim of this study was to investigate the possible connections of paraben exposure and obesity. Blood plasma from 27 healthy women was collected during their menstrual cycle. Basal anthropometric measures, levels of parabens (methylparaben, ethylparaben and propylparaben), adipokines (adiponectin, adipsin, leptin, resistin and visfatin) and hormones affecting energy balance and metabolic health (c-peptide, ghreline, GIP, GLP-1, glucagon, insulin, PAI-1) were measured. A Kolmogorov-Smirnov test showed higher methylparaben and propylparaben levels in women with BMI 25-34.9 compared to those with BMI 18.5-24.9. Plasma levels of methylparaben as well as the sum of parabens were positively associated with the plasma adipsin levels. Negative associations for methylparaben were found for glucagon, leptin and PAI-1. In accordance with other experimental studies we observed important associations of methylparaben and hormones affecting energy balance and metabolic health, indicating its obesogenic potential.

Biodegradation of four selected parabens with aerobic activated sludge and their transesterification product.

Parabens are preservatives widely used in foodstuffs, cosmetics and pharmaceuticals, which have led to elevated paraben concentrations in wastewater and receiving waters. Laboratory-scale batch experiments were conducted to investigate the adsorption and degradation of parabens in an aerobic activated sludge system. Results show that biodegradation plays a key role in removing parabens from the aerobic system of wastewater treatment plants, while adsorption on the sludge is not significant. The effects of parent paraben concentration, concentration of mixed liquor suspended solids (MLSS), initial pH and temperature on degradation were investigated using kinetic models. The data shows that the degradation of parabens could be described by the first-order kinetic model with the rate constant ranging from 0.10 to 0.88 h-1 at 25 °C and pH 7.0. Paraben degradation can be enhanced by increasing the MLSS concentration and temperature, or by decreasing the parent paraben concentration. Furthermore, the pH of the incubation system should be lower than 8.0. The half-lives of the parabens were estimated to range between 0.79 and 6.9 h, with methylparaben exhibiting the slowest degradation rate. During degradation in the present system, transesterification occurred, with methylparaben being the major transformation product in the incubation systems of ethylparaben, propylparaben and butylparaben. These results were confirmed by mass spectrometry and aliphatic alcohol additive experiments. This is the first discovery of paraben transesterification in an activated sludge system, and it is associated with trace methanol in the system.

Inter- and intra-individual variation in urinary concentrations of parabens in male and female Japanese subjects.

We evaluated the representativeness of concentrations of parabens in a spot urine sample for the assessment of long-term exposure levels. Urine sample was taken monthly from 10 male Japanese subjects (35.9 ± 6.8 years) and 12 female Japanese university students (21.1 ± 0.4 years) for 5 months and measured for methyl (MP), ethyl (EP), propyl (PP) and butyl (BP) parabens by liquid chromatography-tandem mass spectrometry. Median (min-max) specific-gravity-adjusted urinary concentrations of the male group (n = 10) were 39.7 (2.99-268), 1.69 (< 0.045-75.2), 0.569 (< 0.11-123) and 0.0264 (< 0.020-24.4) ng mL-1 for MP, EP, PP and BP, respectively. Those of the female group (n = 12) were 283 (5.49-1687), 9.30 (0.290-487), 22.9 (< 0.11-307) and 3.76 (< 0.020-135) ng mL-1, respectively, which were significantly higher than those of the male group. Intra-class correlation coefficients (ICCs) were calculated for the four parabens to find 0.56, 0.58, 0.39 and 0.28 for MP, EP, PP and BP, respectively, in the male group, and 0.40, 0.43, 0.41 and 0.37 for MP, EP, PP and BP, respectively, in the female group. The results suggested that four paraben concentrations in a spot urine sample moderately reflected long-term paraben exposure of Japanese subjects. Source of exposure to parabens is also discussed.

Human Semen Quality, Sperm DNA Damage, and the Level of Reproductive Hormones in Relation to Urinary Concentrations of Parabens.

OBJECTIVE: The aim of this study was to evaluate the association between environmental exposure to parabens and semen quality parameters [main semen parameters, computer-aided semen analysis (CASA parameters], sperm chromatin structure, and the level of reproductive hormones in men [follicle-stimulating hormone (FSH), testosterone, estradiol]. METHODS: Urine samples collected from 315 men who attended the infertility clinic for diagnostic purposes with normal semen concentration of 15 to 300 mln/mL were analyzed for five parabens concentrations using a validated gas chromatography ion-tap mass spectrometry method. Participants were interviewed and also provided a semen, saliva, and blood samples. RESULTS: Urinary parabens concentrations were significantly associated with an increase in the percentage of sperm with abnormal morphology, in sperm with high DNA stainability and a decrease in the percentage of motility and testosterone level. CONCLUSIONS: This is one of the first study on this topic, so the observation of the relationship between parabens and semen quality warrants further investigation.

Environmental exposure to parabens and sperm chromosome disomy.

Parabens are widely used as antimicrobial preservatives in cosmetics, pharmaceuticals, food and beverage processing due to their board spectrum of activity, inertness, and low cost. The study population consisted of 156 men under 45 years of age who attended the infertility clinic for diagnostic purposes with normal semen concentration of 15-300 mln/ml. Participants were interviewed and provided a semen sample. The parabens concentrations: ethyl paraben (EP), butyl paraben (BP), methyl paraben (MP), and iso-butyl paraben (iBuP) were analyzed in the urine using a validated gas chromatography ion-tap mass spectrometry method. The positive association was found between urinary level of BP and XY18 disomy (p = 0.045) and PP and disomy of chromosome 13 (p = 0.007). This is the first study to examine these relationships, and replication of our findings is needed before the association between parabens concentration in urine and aneuploidy can be fully defined. These findings may be of concern due to increased parabens use.

In vitro skin absorption tests of three types of parabens using a Franz diffusion cell.

The objective of this study was to evaluate the permeation of paraben derivatives - methylparaben (MP), propylparaben (PP), and butylparaben (BP) - in hairless mouse full skin and human cadaver epidermis using a Franz diffusion cell method, which is proposed as a reliable alternative method to an skin absorption test. Parabens, esterified hydroxybenzoic acid compounds, are widely used as preservatives in food, cosmetics, and pharmaceutical products. The skin permeation rate showed dose dependency, and the hairless mouse full skin showed a higher flux value than human cadaver epidermis. Among the permeability coefficient (Kp) values of three parabens, MP showed a higher Kp value than PP or BP. Hence, according to the definitions of Marzulli et al., parabens would be classified as "moderate" penetrants.

Metabolism and elimination of methyl, iso- and n-butyl paraben in human urine after single oral dosage.

Parabens are used as preservatives in personal care and consumer products, food and pharmaceuticals. Their use is controversial because of possible endocrine disrupting properties. In this study, we investigated metabolism and urinary excretion of methyl paraben (MeP), iso-butyl paraben (iso-BuP) and n-butyl paraben (n-BuP) after oral dosage of deuterium-labeled analogs (10 mg). Each volunteer received one dosage per investigated paraben separately and at least 2 weeks apart. Consecutive urine samples were collected over 48 h. In addition to the parent parabens (free and conjugated) which are already used as biomarkers of internal exposure and the known but non-specific metabolites, p-hydroxybenzoic acid (PHBA) and p-hydroxyhippuric acid (PHHA), we identified new, oxidized metabolites with hydroxy groups on the alkyl side chain (3OH-n-BuP and 2OH-iso-BuP) and species with oxidative modifications on the aromatic ring. MeP represented 17.4 % of the dose excreted in urine, while iso-BuP represented only 6.8 % and n-BuP 5.6 %. Additionally, for iso-BuP, about 16 % was excreted as 2OH-iso-BuP and for n-BuP about 6 % as 3OH-n-BuP. Less than 1 % was excreted as ring-hydroxylated metabolites. In all cases, PHHA was identified as the major but non-specific metabolite (57.2-63.8 %). PHBA represented 3.0-7.2 %. For all parabens, the majority of the oral dose captured by the above metabolites was excreted in the first 24 h (80.5-85.3 %). Complementary to the parent parabens excreted in urine, alkyl-chain-oxidized metabolites of the butyl parabens are introduced as valuable and contamination-free biomarkers of exposure.

"Parabenoia" Debunked, or "Who's Afraid of Parabens?".

Parabens have been used as preservatives in foods, injectables, and topical preparations for nearly 10 decades. Present in nature, rapidly metabolized by skin and liver enzymes, they have an excellent safety record. However, in the past 15 years, they have been under scrutiny for their alleged estrogenic and antiandrogenic effects, as well as their putative role in promoting cancerogenesis through endocrine disruption. Scientific articles supporting these assertions have led the European Community to ban or restrict the use of some parabens. Despite that methylparaben and ethylparaben have negligible endocrine disruption activity, the food, pharmaceutical, and cosmetic industries are under pressure from scare campaigns in the media and are responding by replacing parabens with other biocides that cause multiple cases, and even worldwide epidemics, of allergic contact sensitization. In the present review, we present a balanced account of the published literature about the metabolism and potential toxicology of parabens.

Stress Tolerance of Antibody-Poly(Amino Acid) Complexes for Improving the Stability of High Concentration Antibody Formulations.

The stabilization of antibodies in aqueous solution against physical stress remains a problematic issue for pharmaceutical applications. Recently, protein-polyelectrolyte complex (PPC) formation using poly(amino acids) was proposed to prepare antibody formulation in a salt-dissociable precipitated state without protein denaturation. Here, we investigated the stabilization effect of PPC of therapeutic antibodies with poly-l-glutamic acid on agitation and thermal stress as forms of mechanical and non-mechanical stress, respectively. The precipitated state of PPC prevented the inactivation and aggregation induced by agitation. Similar results were obtained using the suspension state of PPC, but the stabilizing effects were slightly inferior to those of the PPC precipitate. PPC precipitate and PPC suspension prevented heat-induced inactivation of the antibodies, but showed little effect on heat-induced aggregation. Thus, PPC is a new candidate as a simple storage method for antibodies in aqueous solution, as an alternative state for freeze-drying.

Thimerosal compromises human dendritic cell maturation, IL-12 production, chemokine release, and T-helper polarization.

Thimerosal is a preservative used in multidose vials of vaccine formulations to prevent bacterial and fungal contamination. We recently reported that nanomolar concentrations of thimerosal induce cell cycle arrest of human T cells activated via the TCR and inhibition of proinflammatory cytokine production, thus interfering with T-cell functions. Given the essential role of dendritic cells (DCs) in T-cell polarization and vaccine immunity, we studied the influence of non-toxic concentrations of thimerosal on DC maturation and functions. Ex-vivo exposure of human monocyte-derived DCs to nanomolar concentrations of thimerosal prevented LPS-induced DC maturation, as evidenced by the inhibition of morphological changes and a decreased expression of the maturation markers CD86 and HLA-DR. In addition thimerosal dampened their proinflammatory response, in particular the production of the Th1 polarizing cytokine IL-12, as well as TNF-α and IL-6. DC-dependent T helper polarization was altered, leading to a decreased production of IFN-γ IP10 and GM-CSF and increased levels of IL-8, IL-9, and MIP-1α. Although multi-dose vials of vaccines containing thimerosal remain important for vaccine delivery, our results alert about the ex-vivo immunomodulatory effects of thimerosal on DCs, a key player for the induction of an adaptive response.

Parabens. From environmental studies to human health.

Parabens are a group of substances commonly employed as preservatives, mainly in personal care products, pharmaceuticals and food. Scientific reports concerning their endocrine disrupting potential and the possible link with breast cancer raised wide discussion about parabens' impact and safety. This paper provides holistic overview of paraben usage, occurrence in the environment, methods of their degradation and removal from aqueous solution, as well as hazards related to their endocrine disrupting potential and possible involvement in carcinogenesis.

Evaluation of commercial boric acid containing vials for urine culture: low risk of contamination and cost effectiveness considerations.

BACKGROUND: Urine culture is a gold standard in the diagnosis of urinary tract infection. Clean catch midstream urine collection and prompt transportation is essential for appropriate diagnosis. Improper collection and delay in transportation leads to diagnostic dilemma. In developing countries, higher ambient temperatures further complicate the scenario. Here, we have evaluated the role of boric acid as a preservative for urine samples prior to culture in female patients attending outpatient department at our center. MATERIALS AND METHOD: Consecutive 104 urine samples were cultured simultaneously in plain uricol (Control-C) and boric acid containing tubes from Becton Dickinson urine culture kit (Boric acid group-BA). RESULTS: In the real-time evaluation, we found that in almost 57% (59/104) of the urine samples tested, it was more effective in maintaining the number of the organisms as compared to samples in the container without any preservative. Our in vitro study of simulated urine cultures revealed that urine samples could be kept up to 12 h before culture in the preservative without any inhibitory effect of boric acid. Though the use of boric acid kit may marginally increase the initial cost but has indirect effects like preventing delays in treatment and avoidance of false prescription of antibiotics. If the man-hours spent on repeat investigations are also taken into consideration, then the economic cost borne by the laboratory would also decrease manifold with the use of these containers.