Outbreak of accidental hexachlorophene poisoning in France

Determination of hexachlorophene residue in fruits and vegetables by ultra-high performance liquid chromatography-tandem mass spectrometry

A modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) -LC-MS/MS method was developed for the determination of hexachlorophene in fruits and vegetables. Samples were extracted by acetonitrile and then salted with an acetate buffer system. Extractants neutral alumina (Al-N), strong cation exchange silica gel bonded adsorbent (SCX) and graphitized carbon black (GCB) were used for sample purification. The method demonstrates excellent accuracy and reproducibility. Under optimized conditions, the correlation coefficients of hexachlorophene were higher than 0.995 in the range of 0.5-20 ng/mL. The limit of quantification (LOQ) was 2.0 μg/kg. The average recoveries, assessed at three spiked levels (2.0, 4.0, and 20.0μg/kg) across various matrices including cabbage, celery, tomato, eggplant, potato, radish, cowpea, chives, apple, peach, grape, citrus, bitter melon, banana and hami melon ranged from 72.0 to 100.5% with relative standard deviations from 3.2 to 9.8% (n = 6).

Revolutionizing transdermal drug delivery: unveiling the potential of cubosomes and ethosomes

The area of drug delivery systems has witnessed significant advancements in recent years, with a particular focus on improving efficacy, stability, and patient compliance. Transdermal drug delivery offers numerous benefits compared to conventional methods of drug administration through the skin. It helps in avoiding gastric irritation, hepatic first-pass metabolism, and gastric degradation of the drug. It bypasses the gastrointestinal tract, eliminating the risk of first-pass metabolism and allowing drugs to be administered without being affected by pH, enzymes, or intestinal bacteria. Additionally, it allows for sustained release of the drug, is noninvasive, and enhances patient adherence to the treatment regimen. The transdermal drug delivery system (TDDS) can serve as an alternative route for drug administration in individuals who cannot tolerate oral medications, experience nausea, or are unconscious. When compared to intravenous, hypodermic, and other parenteral routes, TDDS stands out due to its ability to eliminate pain, reduce the risk of infection, and prevent disease transmission associated with needle reuse. Consequently, the overall patient compliance is significantly improved with the utilization of TDDS. Among the noteworthy developments are cubosomes and ethosomes, two distinct yet promising carriers that have garnered attention for their unique properties. In conclusion, this review synthesizes the current knowledge on cubosomes and ethosomes, shedding light on their individual strengths and potential synergies. The exploration of their application in various therapeutic areas underscores their versatility and establishes them as key players in the evolving landscape of drug delivery systems.

New Insights in Topical Drug Delivery for Skin Disorders: From a Nanotechnological Perspective

Skin, the largest organ in humans, is an efficient route for the delivery of drugs as it circumvents several disadvantages of the oral and parenteral routes. These advantages of skin have fascinated researchers in recent decades. Drug delivery via a topical route includes moving the drug from a topical product to a locally targeted region with dermal circulation throughout the body and deeper tissues. Still, due to the skin's barrier function, delivery through the skin can be difficult. Drug delivery to the skin using conventional formulations with micronized active components, for instance, lotions, gels, ointments, and creams, results in poor penetration. The use of nanoparticulate carriers is one of the promising strategies, as it provides efficient delivery of drugs through the skin and overcomes the disadvantage of traditional formulations. Nanoformulations with smaller particle sizes contribute to improved permeability of therapeutic agents, targeting, stability, and retention, making nanoformulations ideal for drug delivery through a topical route. Achieving sustained release and preserving a localized effect utilizing nanocarriers can result in the effective treatment of numerous infections or skin disorders. This article aims to evaluate and discuss the most recent developments of nanocarriers as therapeutic agent vehicles for skin conditions with patent technology and a market overview that will give future directions for research. As topical drug delivery systems have shown great preclinical results for skin problems, for future research directions, we anticipate including in-depth studies of nanocarrier behavior in various customized treatments to take into account the phenotypic variability of the disease.

The sensitivity of the zebrafish embryo coiling assay for the detection of neurotoxicity by compounds with diverse modes of action

In the aim to determine neurotoxicity, new methods are being validated, including tests and test batteries comprising in vitro and in vivo approaches. Alternative test models such as the zebrafish (Danio rerio) embryo have received increasing attention, with minor modifications of the fish embryo toxicity test (FET; OECD TG 236) as a tool to assess behavioral endpoints related to neurotoxicity during early developmental stages. The spontaneous tail movement assay, also known as coiling assay, assesses the development of random movement into complex behavioral patterns and has proven sensitive to acetylcholine esterase inhibitors at sublethal concentrations. The present study explored the sensitivity of the assay to neurotoxicants with other modes of action (MoAs). Here, five compounds with diverse MoAs were tested at sublethal concentrations: acrylamide, carbaryl, hexachlorophene, ibuprofen, and rotenone. While carbaryl, hexachlorophene, and rotenone consistently induced severe behavioral alterations by ~ 30 h post fertilization (hpf), acrylamide and ibuprofen expressed time- and/or concentration-dependent effects. At 37-38 hpf, additional observations revealed behavioral changes during dark phases with a strict concentration-dependency. The study documented the applicability of the coiling assay to MoA-dependent behavioral alterations at sublethal concentrations, underlining its potential as a component of a neurotoxicity test battery.

Skin Barrier Function in Infants: Update and Outlook

A good understanding of infant skin should provide a rationale for optimum management of the health of this integument. In this review, we discuss the skin barrier function of infants, particularly with reference to the use of diapers and baby wipes. The skin barrier of newborns continues to develop with age. Two years after birth, the barrier properties of infant skin closely resemble those of adult skin. However, several risk factors may contribute to impaired skin barrier and altered skin permeability in infants. Problems may arise from the use of diapers and baby wipes. The skin covered by a diaper is effectively an occluded environment, and thus is vulnerable to over-hydration. To date there has been no published information regarding dermal absorption of ingredients contained in baby wipes. Similarly, dermal absorption of topical ingredients in infants with underlying skin conditions has not been widely explored. Clearly, there are serious ethical concerns related to conducting skin permeation studies on infant skin. However, the increasing availability of non-invasive methods for in vivo studies is encouraging and offers new directions for studying this important patient group.

Topical drug delivery: History, percutaneous absorption, and product development

Topical products, widely used to manage skin conditions, have evolved from simple potions to sophisticated delivery systems. Their development has been facilitated by advances in percutaneous absorption and product design based on an increasingly mechanistic understanding of drug-product-skin interactions, associated experiments, and a quality-by-design framework. Topical drug delivery involves drug transport from a product on the skin to a local target site and then clearance by diffusion, metabolism, and the dermal circulation to the rest of the body and deeper tissues. Insights have been provided by Quantitative Structure Permeability Relationships (QSPR), molecular dynamics simulations, and dermal Physiologically Based PharmacoKinetics (PBPK). Currently, generic product equivalents of reference-listed products dominate the topical delivery market. There is an increasing regulatory interest in understanding topical product delivery behavior under 'in use' conditions and predicting in vivo response for population variations in skin barrier function and response using in silico and in vitro findings.

Twenty Clinically Pertinent Factors/Observations for Percutaneous Absorption in Humans

At least 20 clinically relevant factors affect percutaneous absorption of drugs and chemicals: relevant physico-chemical properties, vehicle/formulation, drug exposure conditions (dose, duration, surface area, exposure frequency), skin appendages (hair follicles, glands) as sub-anatomical pathways, skin application sites (regional variation in penetration), population variability (premature, infants, and aged), skin surface conditions (hydration, temperature, pH), skin health and integrity (trauma, skin diseases), substantivity and binding to different skin components, systemic distribution and systemic toxicity, stratum corneum exfoliation, washing-off and washing-in, rubbing/massaging, transfer to others (human to human and hard surface to human), volatility, metabolic biotransformation/cutaneous metabolism, photochemical transformation and photosensitivity, excretion pharmacokinetics, lateral spread, and chemical method of determining percutaneous absorption.

Stratum corneum substantivity: drug development implications

There are at least 15 factors that influence the ability of chemicals to penetrate the skin. Substantivity is yet another factor and allows penetrants to remain on and in skin for many days. As many skin pathologies involve stratum corneum and require multiple dosing of topicals, understanding substantivity mechanisms may provide insight for topical dosing strategies. Substantivity is also of importance in the development of other consumer products that necessitate adherence to skin, including sunscreens, insect repellents, and cosmetics. Furthermore, while stratum corneum adherence may delay percutaneous penetration, reducing the risk of systemic toxicity, excessive substantivity may play a role in the toxic accumulation of harmful penetrants. Continued research in this area may offer insight into dermatotoxicology and dermatopharmacology.

Poisoning Through Pediatric Skin: Cases from the Literature

Poisoning through pediatric skin leading to acute systemic symptoms is a relatively uncommonly reported phenomenon. Systemic toxicity through the skin typically occurs by direct contact between therapeutic or non-therapeutic topical agents and the skin. Though uncommon, poisoning through pediatric skin can have significant consequences and must be recognized so the offending agent may be discontinued and appropriate treatment initiated. We performed a literature search for all article types between 1950 and April 2016 to provide a single source of detectable cases of acute toxicity in pediatric patients due to percutaneous exposure. This literature review discusses relevant pediatric skin physiology along with reports of poisoning events that resulted in systemic signs and symptoms and even death to provide a comprehensive report on causes of pediatric poisoning through the skin.

Longitudinal diffusion tensor imaging of the rat brain after hexachlorophene exposure

Longitudinal MRI employing diffusion tensor imaging and T₂ mapping approaches has been applied to investigate the mechanisms of white matter damage caused by acute hexachlorophene neurotoxicity in rats in vivo. Male Sprague-Dawley rats were administered hexachlorophene orally once a day for five consecutive days at a dose of 30mg/kg and were monitored in 7T MRI scanner at days 0 (baseline), 3, 6, 13, and 20 following the first hexachlorophene dose. Quantitative T₂ maps as well as a number of diffusion tensor parameters (fractional anisotropy, radial and axial diffusivity, apparent diffusion coefficient, and trace) were calculated from corresponding MR images. T₂, as well as all diffusion tensor derived parameters (except fractional anisotropy) showed significant changes during the course of neurotoxicity development. These changes peaked at 6days after the first dose of hexachlorophene (one day after the last dose) and recovered to practically baseline levels at the end of observation (20days from the first dose). While such changes in diffusivity and T₂ relaxation clearly demonstrate myelin perturbations consistent with edema, the lack of changes of fractional anisotropy suggests that the structure of the myelin sheath was not disrupted significantly by hexachlorophene in this study. This is also confirmed by the rapid recovery of all observed MRI parameters after cessation of hexachlorophene exposure.

Chemically Induced Myelinopathies

The diverse, structurally unrelated chemicals that cause toxic myelinopathies have been investigated and can be categorized into two types of primary demyelinators. Some demyelinating chemicals seem to leave intact the myeli-nating cells (oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system), while others damage the myelinating cells as well as the myelin. The significance between the two is that with the myelinating cells still in tact, repair of the myelin sheath can occur. However, if the myelinating cells are destroyed, repair and reversal of the neuropathy may not occur. Histologically, these chemicals produce an edema of the white matter of the brain, and in some cases the peripheral nervous system, that appears spongy by light microscopy. By electron microscopy, vacuoles can be seen in the myelin surrounding axons. These vacuoles are characterized as fluid-filled separations (splitting) of myelin lamellae at the intraperiod line. In some cases these vacuoles can degenerate further to full demyelination, affecting conduction through those axons. Regeneration of the myelin layers can occur, and in some cases occurs at the same time other axons are undergoing toxic demyelination. Several of these chemicals, however, have been shown to increase cerebrospinal fluid pressure in the brain, optic nerve, and spinal cord, and/or intraneuronal pressure in the perineurium surrounding the axons in the peripheral nervous system. This increased pressure has been correlated with decreased conduction capacity through the axon, ischemia to the neuronal tissue from decreased blood flow because of pressure against the blood vessels, and, if unrelieved, permanent axonal damage. Several of these chemicals havebeen shown to inhibit oxidative phosphorylation, while others uncouple oxidative phosphorylation. One chemical appears to inhibit an enzyme critical to cholesterol synthesis, thus destabilizing myelin. Another hypothesis for a mechanism of action may be in the ability of these compounds to alter membrane permeability.

From Phenoxyacetic Acids to Cellular Telephones: Is There Historical Evidence for the Precautionary Principle in Cancer Prevention?

In the late 1970s, the author and his colleagues published the first scientific evidence of an association between exposure to phenoxyacetic acids and chlorophenols and certain malignant tumors; the study subjects were also exposed to contaminating dioxins such as 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD). The results have been corroborated in other studies. Over the years, industry and its allied experts have attacked these studies, but in 1997 IARC classified TCDD as a human carcinogen, Group I. The author and colleagues found an increased risk of non-Hodgkins lymphoma (NHL) for subjects exposed to these chemicals or to some persistent organic pollutants; the increasing incidence in Sweden leveled off in about 1990. The author postulated that the regulation of or ban on these chemicals in Sweden in the 1970s contributed to the now decreasing incidence of NHL. Recent findings of an association between cellular telephones and brain tumors have provoked much unfounded criticism from industry and from the Swedish Radiation Protection Authority. Thus the precautionary principle is prohibited and early warnings of a cancer risk ignored. The experience of cancer risks from certain chlorinated phenols may serve as a model of how the precautionary principle could be used to take early warnings seriously. Unfortunately, the lessons of history seem to go unheeded, as exemplified by the case of cellular telephones.

Learning Lessons from Adverse Drug Reactions in Children

Drug toxicity is, unfortunately, a significant problem in children both in the hospital and in the community. Drug toxicity in children is different to that seen in adults. At least one in 500 children will experience an adverse drug reaction each year. For children in hospital, the risk is far greater (one in ten). Additionally, different and sometimes unique adverse drug reactions are seen in the paediatric age groups. Some of the major cases of drug toxicity historically have occurred in neonates. It is important that we understand the mechanism of action of adverse drug reactions. Greater understanding alongside rational prescribing should hopefully reduce drug toxicity in children in the future.

Transdermal patches: history, development and pharmacology

Transdermal patches are now widely used as cosmetic, topical and transdermal delivery systems. These patches represent a key outcome from the growth in skin science, technology and expertise developed through trial and error, clinical observation and evidence-based studies that date back to the first existing human records. This review begins with the earliest topical therapies and traces topical delivery to the present-day transdermal patches, describing along the way the initial trials, devices and drug delivery systems that underpin current transdermal patches and their actives. This is followed by consideration of the evolution in the various patch designs and their limitations as well as requirements for actives to be used for transdermal delivery. The properties of and issues associated with the use of currently marketed products, such as variability, safety and regulatory aspects, are then described. The review concludes by examining future prospects for transdermal patches and drug delivery systems, such as the combination of active delivery systems with patches, minimally invasive microneedle patches and cutaneous solutions, including metered-dose systems.

Paediatric medicines research in the UK: how to move forward?

There have been numerous studies to show that many of the medicines used in children are used off-label or are unlicensed for use in children. When children are prescribed unlicensed and off-label medications, some people may see them as unknowing participants in informal and uncontrolled experiments. However, the licensing status of a drug can be seen as a by-product of the real issues: the safety, efficacy and quality of these medicines in the current licensing system. It is important to conduct research in order to provide high quality data regarding safety and efficacy to support evidence-based paediatric prescribing. Clinical trials will always be an invaluable means of acquiring vital information about a drug; but when it comes to children, we may find that these trials are not always practical for technical, ethical and financial reasons; therefore, it is important to explore other methodologies in paediatric medicines research. Pharmacoepidemiological and prospective cohort studies could provide vital safety and efficacy data on paediatric medicines; however, resources need to be invested in the methodological research. Paediatric drug formulation research is under-resourced and under-valued, and, unfortunately, fatal and serious adverse reactions due to inappropriate formulations have been reported in many instances. Paediatric medication is a complex problem; we need to use all available tools for research on safety, efficacy and formulation. The reason for lack of progress in paediatric drug research is most likely due to lack of resources and research capacity. The industry and government should work together and invest more money in paediatric drug research. Finally, regulatory authorities, healthcare professionals and academics need to rethink the research strategy in order to provide better medicines for children.

Systemic lupus erythematosus with multiple perivascular spongy changes in the cerebral deep structures, midbrain and cerebellar white matter: a case report

A 42-year-old woman with systemic lupus erythematosus developed an episode of tonic seizures and progressive disturbance of consciousness at the terminal stage. Neuropathological examination of the brain revealed a nearly symmetrical distribution of multiple spongy foci in the internal capsules, thalami, globus pallidus, mesencephalic tegmentum, cerebral peduncles and hilus of the dentate nuclei. The spongy lesions were obviously distributed along apparently intact medium-sized veins, and contained large numbers of macrophages, and axonal spheroids and a few reactive astrocytes, without inflammatory cell infiltration. In addition, the perivenous spongy lesions exhibited IgG immunoreactivity, so it is surmised that some neurotoxic factor(s) that exuded from the veins in the center of the perivenous lesions may have brought about such a unique pathology.

What cord care--if any?

The use of antiseptic treatment during cord care varies from unit to unit. Although it may reduce bacterial colonisation it may also delay cord separation. Where antiseptic treatment is used there is uncertainty as to the best agent. Hexachlorophane powder (0.3%) and 4% chlorhexidene detergent were each compared with dry cord care as a control on a two ward maternity unit in a six month open study. Of 133 infants treated with hexachlorophane 44 (33%) became heavily colonised with Staphylococcus aureus compared with 80 (47%) of 171 controls; a reduction of one third. Chlorhexidene reduced colonisation by more than half; 17 (16%) of 104 compared with 41 (42%) of 98 controls. Chlorhexidene was associated with cord attachment at 10 days in 29 (28%) infants compared with 31 of 515 (6%) infants when it was not used. Hexachlorophane was more acceptable to the nursing staff. The reduction in colonisation with the two compounds was largely due to the suppression of cross infection.

Handling toxicoses of unknown origin

A strategy is presented for investigating toxicoses of unknown origin and following a disease-oriented approach. The strategy is derived from and illustrated by experience of three large scale outbreaks of disease involving aflatoxicosis in India, intoxication by pyrrolizidine alkaloids from Heliotropium spp. in Afghanistan and from Crotalaria spp. in India. Investigation of such cases involves a descriptive phase (case definition, descriptive pattern of disease), hypothesis generation (based on pathologic studies and indications from environmental and epidemiological investigations), hypothesis testing and confirmatory studies. After establishing a causal relationship, steps need to be taken to transmit information to health authorities, to disseminate knowledge to health delivery personnel and the general public, to identify borderline cases and plan management, to identify mechanisms of exposure/contamination and relevant measures to remove or minimize exposure to the causal agent.

Hexachlorophene toxicosis in a litter of Doberman pinschers

A litter of 5-week-old Doberman Pinschers with pustular dermatitis was treated dermally with a hexachlorophene-containing emulsion. Shortly after a second treatment, all of the puppies developed neurologic signs consisting of muscle tremors, ataxia, and apparent muscle weakness. The clinical history and signs, histologic lesions within the central nervous system, and measurement of hexachlorophene in liver and kidney tissue confirmed a diagnosis of hexachlorophene toxicosis.

Haemorrhagic shock and encephalopathy: a new syndrome with a high mortality in young children

In the past year, ten infants have been admitted to hospital with a new or previously unrecognised disorder, characterised by an acute onset of encephalopathy, fever, shock, watery diarrhoea, severe disseminated intravascular coagulation, and renal and hepatic dysfunction. Seven of the infants died. No specific causative agent has been identified, but preliminary studies suggest that the pathophysiology of the disease may involve release of proteolytic enzymes (such as trypsin) into the circulation, with destruction of the microcirculation.

Placental transfer of hexachlorophene (HCP) in the marmoset monkey (Callithrix jacchus)

Autoradiography was used to study the distribution of 2,2'-14C-methylene-bis-(3,4,6-trichlorophenol) (HCP) in pregnant marmoset monkeys in early (day 30-50) and late (around day 120) gestation and in a newborn (11 days old) pup. Radioactivity was present in the conceptus at all stages of gestation, although the foetal concentration was lower than the maternal. In the embryo an accumulation was observed in the neural tube and in the embryonic membranes. In the late foetus and newborn monkey the highest concentration of radioactivity was found in the liver and the intestinal contents. The brain of the adult and newborn animals showed low concentration. A partial blood-brain barrier was present in the late foetus but, in relation to other tissues, the foetal brain concentration was higher than that of the mother.

Barrier properties of the newborn infant's skin

The barrier properties of the skin were examined in 223 studies in 70 newborn infants of 25 to 41 weeks' gestation, aged from 1 hour to 26 days. Percutaneous drug absorption was studied by observing the blanching response to solutions of 1% and 10% phenylephrine applied to a small area of abdominal skin. Skin water loss was measured at the same site using an evaporimeter. Infants of 37 weeks' gestation or more showed little or no drug absorption and had low skin water losses, indicating that their skin is an effective barrier. By contrast, infants of 32 weeks' gestation or less showed marked drug absorption and high skin water losses in the early neonatal period, indicating that their skin is defective as a barrier. Both drug absorption and water loss in these infants fell steadily; by about 2 weeks of age the skin of the most immature infants functioned like that of mature infants. The varying barrier properties can be explained by the poor development of the stratum corneum in the more premature infants at birth and its rapid maturation after birth. The trauma caused to the skin by use of adhesive tape and the fixation of transcutaneous oxygen electrodes resulted in increased drug absorption and water loss from the damaged area.

Hexachlorophene-induced degeneration of adrenergic nerves: application of quantitative image analysis to Falck-Hillarp fluorescence histochemistry

Possible toxic effects of hexachlorophene (HCP) on sympathetic adrenergic nerves were studied using Falck-Hillarp fluorescence histochemistry on whole-mounts of albino rat irides. HCP dissolved in 5 microliters DMSO, or DMSO alone, was injected into the anterior chamber of the eye. HCP caused a dose-dependent degeneration of adrenergic nerves, first observable after 7 micrograms and profound after 21 micrograms. One and 3 days after 35 micrograms of HCP there was an almost total loss of adrenergic nerves. Regeneration from remaining non-terminal axons led to an almost complete reformation of the adrenergic nerve plexus after 18 days. The results demonstrate a new aspect of hexachlorophene neurotoxicity, degeneration of peripheral adrenergic nerve terminals and suggest that neurotoxic actions on thin unmyelinated fiber systems should be looked for also in the central nervous system (CNS).