In vitro antifungal efficacy of ciclopirox olamine alone and associated with zinc pyrithione compared to ketoconazole against Malassezia globosa and Malassezia restricta reference strains

Targeted Delivery of Zinc Pyrithione to Skin Epithelia

Zinc pyrithione (ZnPT) is an anti-fungal drug delivered as a microparticle to skin epithelia. It is one of the most widely used ingredients worldwide in medicated shampoo for treating dandruff and seborrheic dermatitis (SD), a disorder with symptoms that include skin flaking, erythema and pruritus. SD is a multi-factorial disease driven by microbiol dysbiosis, primarily involving Malassezia yeast. Anti-fungal activity of ZnPT depends on the cutaneous availability of bioactive monomeric molecular species, occurring upon particle dissolution. The success of ZnPT as a topical therapeutic is underscored by the way it balances treatment efficacy with formulation safety. This review demonstrates how ZnPT achieves this balance, by integrating the current understanding of SD pathogenesis with an up-to-date analysis of ZnPT pharmacology, therapeutics and toxicology. ZnPT has anti-fungal activity with an average in vitro minimum inhibitory concentration of 10-15 ppm against the most abundant scalp skin Malassezia species (Malassezia globosa and Malassezia restrica). Efficacy is dependent on the targeted delivery of ZnPT to the skin sites where these yeasts reside, including the scalp surface and hair follicle infundibulum. Imaging and quantitative analysis tools have been fundamental for critically evaluating the therapeutic performance and safety of topical ZnPT formulations. Toxicologic investigations have focused on understanding the risk of local and systemic adverse effects following exposure from percutaneous penetration. Future research is expected to yield further advances in ZnPT formulations for SD and also include re-purposing towards a range of other dermatologic applications, which is likely to have significant clinical impact.

Newly Developed Anti-Dandruff Regimen, VB-3222, Delivers Enhanced Sensorial and Effective Therapeutic Benefits Against Moderate Adherent Dandruff

Background

Uninhibited proliferation of Malassezia spp., enhanced sebaceous gland activity and individual sensitivity are three prime etiological factors behind dandruff. For many dandruff sufferers, existing anti-dandruff products start yielding unsatisfactory results after a few cycles of use. This observation made us explore the physical and biological environment of the host and exploit the specific type of lipid dependence of Malassezia spp. for their survival. A shampoo formulation (product code VB-3222) was developed to address the shortcomings of existing therapy.

Purpose

Evaluating efficacy of VB-3222 in comparison to marketed products through  in vitro assays and subsequently demonstrating its advantages in a clinical study.

Methods

VB-3222 was developed with a derivative of medium chain fatty acid (MCFA) and zinc pyrithione and compared against marketed comparators by in vitro time kill assay. Subsequently, VB-3222 shampoo was tested in a 21-day clinical trial on 25 moderate dandruff subjects to evaluate local safety and efficacy.

Results

VB-3222 in all in vitro cases demonstrated significantly better fungicidal activity than its marketed comparators. In the clinical trial, VB-3222 was well tolerated in all subjects and imparted consistent reduction of the ASFS (adherent scalp flaking score) and the pruritus score. At days 7 and 21, 55% and 90% reduction in the ASFS in comparison to treatment initiation and 50% and 95.5% reduction in the pruritus score were observed.

Conclusion

The increased efficacy of VB-3222 over comparator products in vitro, and the dramatic reduction (>90%) in ASFS and pruritis in subjects within 21 days of use with excellent tolerability and sensorial profile, positions VB-3222 as the new generation treatment for adherent dandruff.

Clinical Trial Registration No

CTRI/2018/05/013567.

Plant-Derived Products as Antibacterial and Antifungal Agents in Human Health Care

A number of papers reporting antimicrobial properties of extracts, essential oils, resins and various classes of compounds isolated from higher plants have been published in recent years; however, a comprehensive analysis of plant-derived antimicrobial agents currently applied in practice for the improvement of human health is still lacking. This review summarizes data on clinical efficacy, antimicrobial effects and the chemistry of commercially available antibacterial and antifungal agents of plant origin currently used in the prevention and treatment of gastrointestinal, oral, respiratory, skin, and urinary infections. As a result of an analysis of the literature, more than 40 plant-derived over-the-counter pharmaceuticals, dietary supplements, cosmetics, herbal medicines, and functional foods containing complex mixtures (e.g. Glycyrrhiza glabra extract, Melaleuca alternifolia essential oil, and Pistacia lentiscus resin), pure compounds (e.g. benzoic acid, berberine, eucalyptol, salicylic acid and thymol) as well as their derivatives and complexes (e.g. bismuth subsalicylate and zinc pyrithione) have been identified. The effectiveness of many of these products is illustrated by results of clinical trials and supported by data on there in vitro antimicrobial activity. A broad spectrum of various commercial products currently available on the market and their welldocumented clinical efficacy suggests that plants are prospective sources for the identification of new types of antimicrobial agents in future. Innovative approaches and methodologies for effective proof-of-concept research and the development of new types of plant-derived products effective against recently emerging problems related to human microbial diseases (e.g. antimicrobial resistance) are also proposed in this review.

Understanding the Mechanism of Action of the Anti-Dandruff Agent Zinc Pyrithione against Malassezia restricta

Dandruff is known to be associated with Malassezia restricta. Zinc pyrithione (ZPT) has been used as an ingredient in anti-dandruff treatments. The mechanism of ZPT has been investigated in several studies; however, a non-pathogenic model yeast, such as Saccharomyces cerevisiae was most often used. The aim of the present study was to understand how ZPT inhibits the growth of M. restricta. We analyzed the cellular metal content and transcriptome profile of ZPT-treated M. restricta cells and found that ZPT treatment dramatically increased cellular zinc levels, along with a small increase in cellular copper levels. Moreover, our transcriptome analysis showed that ZPT inhibits Fe-S cluster synthesis in M. restricta. We also observed that ZPT treatment significantly reduced the expression of lipases, whose activities contribute to the survival and virulence of M. restricta on human skin. Therefore, the results of our study suggest that at least three inhibitory mechanisms are associated with the action of ZPT against M. restricta: (i) an increase in cellular zinc levels, (ii) inhibition of mitochondrial function, and (iii) a decrease in lipase expression.

Azole Antifungal Sensitivity of Sterol 14α-Demethylase (CYP51) and CYP5218 from Malassezia globosa

Malassezia globosa cytochromes P450 CYP51 and CYP5218 are sterol 14α-demethylase (the target of azole antifungals) and a putative fatty acid metabolism protein (and a potential azole drug target), respectively. Lanosterol, eburicol and obtusifoliol bound to CYP51 with K_d values of 32, 23 and 28 μM, respectively, catalyzing sterol 14α-demethylation with respective turnover numbers of 1.7 min⁻¹, 5.6 min⁻¹ and 3.4 min⁻¹. CYP5218 bound a range of fatty acids with linoleic acid binding strongest (K_d 36 μM), although no metabolism could be detected in reconstitution assays or role in growth on lipids. Clotrimazole, fluconazole, itraconazole, ketoconazole, voriconazole and ketaminazole bound tightly to CYP51 (K_d ≤ 2 to 11 nM). In contrast, fluconazole did not bind to CYP5218, voriconazole and ketaminazole bound weakly (K_d ~107 and ~12 μM), whereas ketoconazole, clotrimazole and itraconazole bound strongest to CYP5218 (K_d ~1.6, 0.5 and 0.4 μM) indicating CYP5218 to be only a secondary target of azole antifungals. IC₅₀ determinations confirmed M. globosa CYP51 was strongly inhibited by azole antifungals (0.15 to 0.35 μM). MIC₁₀₀ studies showed itraconazole should be considered as an alternative to ketoconazole given the potency and safety profiles and the CYP51 assay system can be used in structure-activity studies in drug development.

Topical treatments for scalp psoriasis

BACKGROUND

People with chronic plaque psoriasis often have lesions on the scalp. Hair makes the scalp difficult to treat and the adjacent facial skin is particularly sensitive to topical treatments.

OBJECTIVES

To assess the efficacy and safety of topical treatments for scalp psoriasis.

SEARCH METHODS

We searched the following databases up to August 2015: the Cochrane Skin Group Specialised Register, CENTRAL (2015, Issue 7), MEDLINE (from 1946), EMBASE (from 1974) and LILACS (from 1982). We also searched five trials registers, screened abstracts of six psoriasis-specific conferences and checked the reference lists of included studies for further references to relevant randomised controlled trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) with a parallel-group, cross-over or within-patient design of topical treatments for people of all ages with scalp psoriasis.

DATA COLLECTION AND ANALYSIS

Two authors independently carried out study selection, data extraction and 'Risk of bias' assessment. Disagreements were settled by reference to a third author.To assess the quality of evidence, we focused on the following outcomes: 'clearance' or 'response' as assessed by the investigator global assessment (IGA), improvement in quality of life, adverse events requiring withdrawal of treatment and 'response' as assessed by the patient global assessment (PGA).We expressed the results of the single studies as risk ratios (RR) with 95% confidence intervals (CI) for dichotomous outcomes, and mean differences (MD) with 95% CI for continuous outcomes. If studies were sufficiently homogeneous, we meta-analysed the data by using the random-effects model. Where it was not possible to calculate a point estimate for a single study, we described the data qualitatively. We also presented the number needed to treat to benefit (NNTB).We categorised topical corticosteroids according to the German classification of corticosteroid potency as mild, moderate, high and very high.

MAIN RESULTS

We included 59 RCTs with a total of 11,561 participants. Thirty studies were either conducted or sponsored by the manufacturer of the study medication. The risk of bias varied considerably among the included studies. For instance, most authors did not state the randomisation method and few addressed allocation concealment. Most findings were limited to short-term treatments, since most studies were conducted for less than six months. Only one trial investigated long-term therapy (12 months). Although we found a wide variety of different interventions, we limited the grading of the quality of evidence to three major comparisons: steroid versus vitamin D, two-compound combination of steroid and vitamin D versus steroid monotherapy and versus vitamin D.In terms of clearance, as assessed by the IGA, steroids were better than vitamin D (RR 1.82; 95% CI 1.52 to 2.18; four studies, 2180 participants, NNTB = 8; 95% CI 7 to 11; moderate quality evidence). Statistically, the two-compound combination was superior to steroid monotherapy, however the additional benefit was small (RR 1.22; 95% CI 1.08 to 1.36; four studies, 2474 participants, NNTB = 17; 95% CI 11 to 41; moderate quality evidence). The two-compound combination was more effective than vitamin D alone (RR 2.28; 95% CI 1.87 to 2.78; four studies, 2008 participants, NNTB = 6; 95% CI 5 to 7; high quality evidence).In terms of treatment response, as assessed by the IGA, corticosteroids were more effective than vitamin D (RR 2.09; 95% CI 1.80 to 2.41; three studies, 1827 participants; NNTB = 4; 95% CI 4 to 5; high quality evidence). The two-compound combination was better than steroid monotherapy, but the additional benefit was small (RR 1.15; 95% CI 1.06 to 1.25; three studies, 2444 participants, NNTB = 13; 95% CI 9 to 24; moderate quality evidence). It was also more effective than vitamin D alone (RR 2.31; 95% CI 1.75 to 3.04; four studies, 2222 participants, NNTB = 3; 95% CI 3 to 4; moderate quality evidence).Reporting of quality of life data was poor and data were insufficient to be included for meta-analysis.Steroids caused fewer withdrawals due to adverse events than vitamin D (RR 0.22; 95% CI 0.11 to 0.42; four studies, 2291 participants; moderate quality evidence). The two-compound combination and steroid monotherapy did not differ in the number of adverse events leading withdrawal (RR 0.88; 95% CI 0.42 to 1.88; three studies, 2433 participants; moderate quality evidence). The two-compound combination led to fewer withdrawals due to adverse events than vitamin D (RR 0.19; 95% CI 0.11 to 0.36; three studies, 1970 participants; high quality evidence). No study reported the type of adverse event requiring withdrawal.In terms of treatment response, as assessed by the PGA, steroids were more effective than vitamin D (RR 1.48; 95% CI 1.28 to 1.72; three studies, 1827 participants; NNTB = 5; 95% CI 5 to 7; moderate quality evidence). Statistically, the two-compound combination was better than steroid monotherapy, however the benefit was not clinically important (RR 1.13; 95% CI 1.06 to 1.20; two studies, 2226 participants; NNTB = 13; 95% CI 9 to 26; high quality evidence). The two-compound combination was more effective than vitamin D (RR 1.76; 95% CI 1.46 to 2.12; four studies, 2222 participants; NNTB = 4; 95% CI 3 to 6; moderate quality evidence).Common adverse events with these three interventions were local irritation, skin pain and folliculitis. Systemic adverse events were rare and probably not drug-related.In addition to the results of the major three comparisons we found that the two-compound combination, steroids and vitamin D monotherapy were more effective than the vehicle. Steroids of moderate, high and very high potency tended to be similarly effective and well tolerated. There are inherent limitations in this review concerning the evaluation of salicylic acid, tar, dithranol or other topical treatments.

AUTHORS' CONCLUSIONS

The two-compound combination as well as corticosteroid monotherapy were more effective and safer than vitamin D monotherapy. Given the similar safety profile and only slim benefit of the two-compound combination over the steroid alone, monotherapy with generic topical steroids may be fully acceptable for short-term therapy.Future RCTs should investigate how specific therapies improve the participants' quality of life. Long-term assessments are needed (i.e. 6 to 12 months).

Clinical and biochemical assessment of maintenance treatment in chronic recurrent seborrheic dermatitis: randomized controlled study

Introduction

Few studies have investigated the long-term effects of a maintenance regimen in the prevention of relapses in scalp seborrheic dermatitis (SD), in particular following biomarker changes.

Materials and methods

A new shampoo containing beta-glycyrrhetinic acid (18βGA) in addition to cyclopiroxolamine (CPO) and zinc pyrithione (ZP) was tested in 67 subjects suffering from SD with moderate to severe erythema and itching in a biphasic study. After a first common intensive treatment phase (investigational product thrice a week × 2 weeks), subjects randomly received the investigational product once a week × 8 weeks (maintenance) or a neutral shampoo (discontinuation) in a comparative, parallel group maintenance phase. Efficacy was assessed clinically (overall clinical dandruff score, erythema, overall efficacy, self-evaluation), biochemically and microbiologically by quantitative polymerase chain reaction (qPCR), high performance liquid chromatography (HPLC) or enzyme-linked immunoabsorbent assay (ELISA) analysis of scale samples (Malassezia species (restricta and globosa), cohesion proteins (plakoglobins), inflammation (Interleukin (IL)-8, IL-1RA/IL-1α) and pruritus (histamine, cathepsin S) markers).

Results

During the intensive treatment phase, SD improved significantly (p < 0.0001) with a decrease in clinical signs as well as Malassezia species, cohesion proteins, inflammation and pruritus markers. During the maintenance phase, the improvement persisted in the ‘maintenance’ group only, with a significant intergroup difference. A consistently positive relationship was found between dandruff, itching, erythema and Malassezia populations, histamine levels and IL-1RA/IL-1α ratio.

Conclusion

The effectiveness of this maintenance regimen was objectively demonstrated at the clinical, biochemical and microbiological level. Correlations between clinical signs and biomarkers could provide clues to explain the resolution of SD and confirm the interest of biomarkers for SD treatment assessment.

Electronic supplementary material

The online version of this article (doi:10.1007/s13555-014-0047-0) contains supplementary material, which is available to authorized users.

Role of topical calcineurin inhibitors in the treatment of seborrheic dermatitis: a review of pathophysiology, safety, and efficacy

Seborrheic dermatitis (SD) is characterized by erythematous pruritic patches and plaques with greasy scale that occur in sebaceous areas. It is common, affecting up to 3% of the population. Past treatments have relied on a wide variety of anti-inflammatory and antifungal agents, but corticosteroids have limited use because of long-term adverse effects. Topical calcineurin inhibitors provide a safe alternative for the treatment of SD, as these drugs block the inflammatory cascade involved in the disease process and pose no risk of skin atrophy. Studies of topical pimecrolimus and tacrolimus in the treatment of SD have found that improvement occurred within 2 weeks, and if SD recurred after stopping treatment, it was significantly less severe. There have been no studies of the comparative efficacy of pimecrolimus versus tacrolimus for the treatment of SD. Common adverse effects of mild burning and irritation have been associated with the use of both of these agents. Safety profile studies are limited to studies of atopic dermatitis, which show no increase in infection rate, photocarcinogenicity, or signs of immunosuppression in patients using topical calcineurin inhibitors for long-term treatment. This article reviews the clinical trials of pimecrolimus and tacrolimus in the treatment of SD, focusing on efficacy and safety.