Pocketed microneedles for rapid delivery of a liquid-state botulinum toxin A formulation into human skin

Botulinum toxin A (BT) is used therapeutically for the treatment of primary focal hyperhidrosis, a chronic debilitating condition characterised by over-activity of the eccrine sweat glands. Systemic toxicity concerns require BT to be administered by local injection, which in the case of hyperhidrosis means multiple painful intradermal injections by a skilled clinician at 6-monthly intervals. This study investigates the potential of a liquid-loaded pocketed microneedle device to deliver botulinum toxin A into the human dermis with the aim of reducing patient pain, improving therapeutic targeting and simplifying the administration procedure. Initially, β-galactosidase was employed as a detectable model for BT to (i) visualise liquid loading of the microneedles, (ii) determine residence time of a liquid formulation on the device and (iii) quantify loaded doses. An array of five stainless steel pocketed microneedles was shown to possess sufficient capacity to deliver therapeutic doses of the potent BT protein. Microneedle-mediated intradermal delivery of β-galactosidase and formaldehyde-inactivated botulinum toxoid revealed effective deposition and subsequent diffusion within the dermis. This study is the first to characterise pocketed microneedle delivery of a liquid formulation into human skin and illustrates the potential of such systems for the cutaneous administration of potent proteins such as BT. A clinically appropriate microneedle delivery system for BT could have a significant impact in both the medical and cosmetic industries.

Pellagra: a review with emphasis on photosensitivity

Niacin has recently been demonstrated to lower blood pressure in hypertensive patients and to reduce cardiovascular events when combined with a statin. As a consequence, niacin has been elevated from being of historical interest as the treatment for pellagra, to being a compound with possible relevance to contemporary therapeutics. In spite of this, niacin deficiency leading to pellagra continues to be a health problem in some countries. Characterized by an exposed-site hyperpigmented dermatitis, pellagra is generally accepted to have been the first photosensitivity syndrome described. At its worst, pellagra manifests as one of the most striking examples of systemic photosensitivity. This is the only photosensitivity syndrome where death is included as a cardinal clinical feature (the often quoted four 'Ds': dermatitis, diarrhoea, dementia and death). However, the pathogenetic mechanism for the photosensitivity caused by niacin deficiency has yet to be determined. This review seeks to update the classification and phenotypic characterization of the various forms of niacin-deficient photosensitivity. Previous speculation about possible mechanisms for the pathogenesis of photosensitivity due to niacin deficiency is reviewed in the context of advances in the understanding of the photochemical basis of photosensitivity reactions. The review concludes by highlighting research required to advance the understanding of this photosensitivity syndrome.

A new scalp formulation of calcipotriol plus betamethasone dipropionate compared with each of its active ingredients in the same vehicle for the treatment of scalp psoriasis: a randomized, double-blind, controlled trial

BACKGROUND

There is a need for new treatments for scalp psoriasis, as many topical treatments are cosmetically unacceptable and difficult to apply, resulting in poor compliance.

OBJECTIVES

To compare the efficacy and safety of a new, once-daily, two-compound scalp formulation (Xamiol; LEO Pharma A/S, Ballerup, Denmark) containing calcipotriol 50 microg g(-1) plus betamethasone 0.5 mg g(-1) (as dipropionate), with the active ingredients as single compounds in the same vehicle.

METHODS

This 8-week, multicentre, double-blind, parallel-group study, randomized adult patients with scalp psoriasis involving > 10% of the scalp to the two-compound scalp formulation (n = 568), betamethasone dipropionate 0.5 mg g(-1) (n = 563), or calcipotriol 50 microg g(-1) (n = 286). The primary efficacy measure was the proportion of patients with 'absence of disease' or 'very mild disease' according to investigators' assessments at week 8.

RESULTS

The proportion of patients with 'absence of disease' or 'very mild disease' at week 8 was significantly higher in the two-compound group (68.4%) than the betamethasone dipropionate (61.0%, P = 0.0079) or calcipotriol (43.4%, P < 0.0001) groups. The proportion of patients rating their scalp psoriasis as 'clear' or 'almost clear' was significantly higher for the two-compound scalp formulation (69.6%) than for betamethasone dipropionate (59.9%, P = 0.0006) or calcipotriol (44.7%, P < 0.0001). The incidence of lesional/perilesional adverse events was lower in the two-compound and betamethasone dipropionate groups than the calcipotriol group.

CONCLUSIONS

The two-compound scalp formulation was well tolerated and more effective in the treatment of scalp psoriasis than either of its individual components in the same vehicle.

Photomedicine: lessons from the Smith-Lemli-Opitz syndrome

The Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive disorder caused by a discrete block in the cholesterol biosynthetic pathway. Recognition of the metabolic basis of this condition has bought into focus knowledge from fields as diverse as clinical genetics, sterol biochemistry, foetal nutrition, and experimental teratology, resulting in a rush of new insights in these fields. Unfortunately, late recognition of photosensitivity as part of this syndrome has largely excluded photodermatologists and photobiologists from the recent frenzy of research in this disorder. However, clinical features of this new inherited photosensitivity syndrome have now been established, and monochromator light testing has confirmed it to be a UVA-mediated condition. Current knowledge concerning photosensitivity in SLOS is reviewed and future research into the pathogenesis of this disorder is discussed.

The dermatosis of chronic granulomatous disease

A family with X-linked cytochrome-negative chronic granulomatous disease (CGD) involving three generations is reported. The diagnosis of CGD in both the latest male patient and the index male was confirmed by marked impairment in polymorphonuclear leucocyte oxidative burst activity in association with absence of both subunits of cytochrome b. The two female carriers have suffered from chronic inflammatory skin disorders characterized by slowly fluctuating erythematous plaques. The reported cases are discussed in the context of a literature review of the dermatosis of CGD.