Arachidonic acid release and prostaglandin E2 synthesis as irritant index of surfactants in 3T6 fibroblast cultures

Quaternary ammonium compounds in hypersensitivity reactions

Quaternary ammonium compounds (QAC) are commonly used disinfectants, antiseptics, preservatives, and detergents due to their antibacterial property and represent the first used biocides before phenolic or nitrogen products. Their common structure consists of one or more quaternary ammonium bound with four lateral substituents. Their amphiphilic structure allows them to intercalate into microorganism surfaces which induces an unstable and porous membrane that explains their antimicrobial activity towards bacteria, fungi, and viruses. QAC are thus found in many areas, such as household products, medicines, hygiene products, cosmetics, agriculture, or industrial products but are also used in medical practice as disinfectants and antiseptics and in health care facilities where they are used for cleaning floors and walls. QAC exposure has already been involved in occupational asthma in healthcare workers or professional cleaners by many authors. They also have been suggested to play a role in contact dermatitis (CD) and urticaria in workers using cosmetics such as hairdressers or healthcare workers, inciting reglementary agencies to make recommendations regarding those products. However, distinguishing the irritant or sensitizing properties of chemicals is complex and as a result, the sensitizing property of QAC is still controverted. Moreover, the precise mechanisms underlying the possible sensitization effect are still under investigation, and to date, only a few studies have documented an immunological mechanism. Besides, QAC have been suggested to be responsible for neuromuscular blocking agents (NMBA) sensitization by cross-reactivity. This hypothesis is supported by a higher prevalence of quaternary ammonium (QA)-specific IgE in the professionally exposed populations, such as hairdressers, cleaners, or healthcare workers, suggesting that the sensitization happens with structurally similar compounds present in the environment. This review summarizes the newest knowledge about QAC and their role in hypersensitivities. After describing the different QAC, their structure and use, the most relevant studies about the effects of QAC on the immune system will be reviewed and discussed.

Biodegradable herbicidal ionic liquids based on synthetic auxins and analogues of betaine

Herbicidal ionic liquids derived from alkylbetaines proved to be biodegradable, thermally stable and highly effective anti-weed agents.

Effect of Travoprost and Nonsteroidal Anti-Inflammatory Drug on Diurnal Intraocular Pressure in Normal Subjects with Low-Teen Baseline Intraocular Pressure

PURPOSE

The main purpose was to determine whether a nonsteroidal anti-inflammatory drug (NSAID) ophthalmic solution would affect the intraocular pressure (IOP)-lowering effect of a benzalkonium chloride (BAK)-free prostaglandin analog, travoprost. The secondary purpose was to confirm the IOP-lowering effect of BAK-free travoprost on the diurnal IOP.

METHODS

This was a prospective, randomized, double-blind, placebo-controlled 1-month trial. After baseline diurnal IOP was confirmed, travoprost was administered once daily to both eyes. Bromfenac sodium hydrate was then randomly assigned to one eye, while flavin adenine dinucleotide sodium was applied to the other eye as a control. Both solutions were administered twice daily. IOP was measured three times daily (8:00, 14:00, and 20:00). The IOP of both groups was compared using Student's t-test. The effect of NSAID on IOP was investigated by repeated measures analysis of variance (ANOVA).

RESULTS

Twenty-eight normal Japanese subjects (mean age, 36.6 years) completed the study. After the start of travoprost, remarkable IOP lowering was gained and it settled to 10-11 mmHg. The diurnal IOPs of the NSAID group showed similar tendencies to that of the control group (P = 0.69-1.0). In a 1-month period, the range of IOP reductions compared with the baseline IOP of both groups showed no significant difference (P = 0.76-0.92). NSAID did not have an influence on IOP (F-value = 0.0036, P = 0.95).

CONCLUSIONS

Although BAK-free travoprost showed a powerful IOP-lowering effect in diurnal and 1-month readings, even in eyes with an IOP of <13 mmHg, the NSAID ophthalmic solution did not affect its IOP-lowering effect.

Low cytotoxic elastic niosomes loaded with salmon calcitonin on human skin fibroblasts

A low cytotoxic elastic niosomal formulation loaded with salmon calcitonin was developed. The elastic niosomes were prepared from Tween 61 mixed with cholesterol at various concentrations of the edge activators (sodium cholate (NaC) and sodium deoxycholate (NaDC); 0.25, 0.5, 2.5, 5 and 10% mole) or ethanol (10–30% v/v). The effects of the niosomal concentrations (5, 10 and 20 mM) and phosphate buffer at pH 7.0 (5, 10, 20 and 30 mM) on the physical characteristics of niosomes were investigated. The 5 mM elastic niosomes in 5 mM phosphate buffer containing calcitonin 0.22 mg/mL gave the highest elasticity (deformability index (DI)) at 6.79 ± 2.03 determined by the extrusion method. The blank elastic niosomes comprised 2.5% mole NaDC, 5% mole NaC or 20% v/v ethanol showed the highest elasticity. The 5% mole NaC elastic niosomes loaded with calcitonin gave the highest DI (21.59 ± 0.91) and percentages of calcitonin entrapment efficiency (60.11 ± 4.98). This study has demonstrated that this NaC elastic niosome did not only reduce the cytotoxicity of the loaded calcitonin but also gave superior cell viability to the ethanolic elastic niosome as well.

Cytotoxicity of submicron emulsions and solid lipid nanoparticles for dermal application

The cytotoxicity and physical properties of various submicron O/W emulsions and solid lipid nanoparticles for dermal applications were investigated. Droplet size and zetapotential of submicron emulsions depended on the composition of the cosurfactant blend used. The viability of J774 macrophages, mouse 3T3 fibroblasts and HaCaT keratinocytes was significantly reduced in the presence of stearylamine. Nanoparticles consisting of stearic acid or different kinds of adeps solidus could be manufactured when formulated with lecithin, sodium taurocholate, polysorbate 80 and stearylamine. Survival of macrophages was highly affected by stearic acid and stearylamine. In general a viability of more than 90% was observed when semi-synthetic glycerides or hard fat was employed to formulate nanoparticles.

Effect of non-steroidal anti-inflammatory ophthalmic solution on intraocular pressure reduction by latanoprost in patients with primary open angle glaucoma or ocular hypertension

AIM

To investigate the effects of a non-steroidal anti-inflammatory drug (NSAID) ophthalmic solution on latanoprost induced intraocular pressure (IOP) reduction in glaucoma patients.

METHODS

Examination was conducted on 16 eyes of 16 glaucoma patients who had been given only latanoprost for at least 6 weeks. The NSAID ophthalmic solution, sodium 2-amino-3-(4-bromobenzoyl) phenylacetate sesquihydrate, was additionally given for 12 weeks into one eye (NSAID group), while sodium hyaluronic acid ophthalmic solution was administered into the other eye (control group) in a double masked fashion. The IOP measurement was performed before the start of additional administration of ophthalmic solutions, 2, 4, 6, 8, 10, and 12 weeks after the start of additional administration, and 2, 4, and 6 weeks after discontinuing additional administration.

RESULTS

No significant difference was observed in the IOPs before additional administration of ophthalmic solution between the NSAID group and the control group. Following the additional administration of ophthalmic solution, IOP in the NSAID group was consistently higher than that in the control group, and a maximum difference in IOP between the two groups was 1.08 (SD 1.75) mm Hg (p = 0.03). This trend was observed even after additional administration was discontinued.

CONCLUSION

NSAID ophthalmic solution may partly affect IOP reduction by latanoprost.

Assessment of primary eye and skin irritants by in vitro cytotoxicity and phototoxicity models: an in vitro approach of new arginine-based surfactant-induced irritation

Extensive efforts have been made, recently, to find surfactants with lower irritation potential than those presently commercially available, for use in pharmaceutical and cosmetic preparations. Cytotoxic and phototoxic effects of a novel family of dicationic arginine-diglyceride surfactant compounds, 1,2-diacyl,3-O-(l-arginyl)-rac-glycerol with alkyl chain lengths in the range from 8 to 14 carbon atoms, were compared to three commercial surfactants. The end-points used to assess toxicity were the red blood cell lysis assay and uptake of the vital dye neutral red 24h after dosing (NRU), respectively. Two immortalized cell lines, murine fibroblast cell line, 3T3, and one human keratinocyte cell line, HaCaT, were used as in vitro models to predict the potential phototoxicity which could result in irritation, determined by resazurin reduction to resorufin and neutral red uptake (NRU). All tested surfactants had cytotoxicity effects as demonstrated by and decrease of NR uptake, which showed a clear concentration-response relationship. Concentrations resulting in 50% inhibition of NR uptake (IC(50)) range from 1 microM(-1) (hexadecyl trimethyl ammonium bromide) to 565 microM(-1) (12,12-l-arginine). Erythrocyte haemolysis also showed a clear concentration-response relationship, the 50% of haemolysis ranged from 37 microM(-1) (10,10-l-arginine) to 151 microM(-1) (sodium lauryl sulphate). Phototoxicity was performed with 12,12-l-acetyl-arginine, the most stable chemical structure. The validated 3T3 NRU photoxicity assay was used and revealed a phototoxic potential.

Procaine-induced enhancement of fluid-phase endocytosis and inhibition of exocytosis in human skin fibroblasts

Local anaesthetics are often applied directly onto the skin, and for this reason the effect of some local anaesthetics upon morphology and cytoskeleton organisation in human skin fibroblasts was investigated. In this paper the authors report that procaine (p-aminobenzoic acid diethylamino-etyl ester hydrochloride) induced vacuolisation of cytoplasm and great enhancement of neutral red accumulation in human skin fibroblasts cultured in vitro. Procaine-induced vacuolisation of cell's cytoplasm was observed to be associated with the enhanced uptake and inhibited release of fluid taken by endocytosis. All these effects appeared fully reversible. The cell vacuolisation cannot be prevented by 3-methyadenine, brefeldine A, and cytochalasine D. On the other hand, nocodazole and caffeine prevent cytoplasm vacuolisation induced by procaine. These observations suggest that procaine-induced formation of great vacuoles is due to an impairment of membrane traffic between endosomes. The authors' results also demonstrate that neutral red uptake assay, if used as a cell viability test, must be interpreted with great caution.

Effect of non-steroidal anti-inflammatory ophthalmic solution on intraocular pressure reduction by latanoprost

AIM

To investigate the effects of a non-steroidal anti-inflammatory drug (NSAID) ophthalmic solution on latanoprost induced intraocular pressure (IOP) reduction using normal volunteers.

METHODS

This study was conducted as a prospective and observer masked clinical trial. 13 normal volunteers were enrolled. After measurement of basal IOP and ophthalmic examination, latanoprost ophthalmic solution was initially administered to both eyes once daily. Four weeks later, an NSAID ophthalmic solution, sodium 2-amino-3-(4-bromobenzoyl) phenylacetate sesquihydrate (refer to bromfenac sodium hydrate), was co-administered to one randomly selected eye (NSAID group) twice daily for 2 weeks. The other eye was employed as a control (non-NSAID group). After withdrawal of the NSAID ophthalmic solution, latanoprost ophthalmic solution was continuously administered for another 2 weeks and was then withdrawn. After a 4 week washout, only bromfenac sodium hydrate ophthalmic solution was administered to the eyes of the NSAID group for 2 weeks. During the study period, ophthalmic examination, including IOP measurement was performed in an observer masked fashion.

RESULTS

Before initiation of bromfenac sodium hydrate, baseline IOPs of the non-NSAID group and the NSAID group were 15.73 (SD 1.97) mm Hg and 15.86 (2.06) mm Hg, respectively (p=0.88). Although latanoprost ophthalmic solution significantly reduced IOP in both groups, co-administration of bromfenac sodium hydrate significantly inhibited latanoprost induced IOP reduction compared with the non-NSAID group. The IOPs of the non-NSAID and NSAID groups were 10.18 (1.17) mm Hg and 11.63 (1.35) mm Hg with a 2 week co-administration, respectively (p <0.01). Withdrawal of bromfenac sodium hydrate ophthalmic solution diminished the difference between the two groups. Re-administration of bromfenac sodium ophthalmic solution only did not affect IOP.

CONCLUSION

These results indicate that NSAID ophthalmic solution may interfere with IOP reduction by latanoprost ophthalmic solution in normal volunteers and that we should take this into account when treating patients with glaucoma using latanoprost ophthalmic solution.