Role of lipids in augmenting the antibacterial activity of benzoyl peroxide against Propionibacterium acnes

A novel long-acting antimicrobial nanomicelle spray

Contaminated surfaces play a major role in disease transmission to humans. The vast majority of commercial disinfectants provide short-term protection of surfaces against microbial contamination. The Covid-19 pandemic has attracted attention to the importance of long-term disinfectants as they would reduce the need for staff and save time. In this study, nanoemulsions and nanomicelles containing a combination of benzalkonium chloride (BKC; a potent disinfectant and a surfactant) and benzoyl peroxide (BPO; a stable form of peroxide that is activated upon contact with lipid/membranous material) were formulated. The prepared nanoemulsion and nanomicelle formulas were of small sizes <80 nm and high positive charge >45 mV. They showed enhanced stability and prolonged antimicrobial efficacy. The antibacterial potency was evaluated in terms of long-term disinfection on surfaces as verified by repeated bacterial inoculums. Additionally, the efficacy of killing bacteria upon contact was also investigated. A nanomicelle formula (NM-3) consisting of 0.8% BPO in acetone and 2% BKC plus 1% TX-100 in distilled water (1 : 5 volume ratio) demonstrated overall surface protection over a period of 7 weeks upon a single spray application. Furthermore, its antiviral activity was tested by the embryo chick development assay. The prepared NM-3 nanoformula spray showed strong antibacterial activities against Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus as well as antiviral activities against infectious bronchitis virus due to the dual effects of BKC and BPO. The prepared NM-3 spray shows great potential as an effective solution for prolonged surface protection against multiple pathogens.

Recent advances in understanding inflammatory acne: Deciphering the relationship between Cutibacterium acnes and Th17 inflammatory pathway

Acne vulgaris is a common chronic inflammatory skin disease of the pilosebaceous units. Four factors contribute to acne: hyperseborrhea and dysseborrhea, follicular hyperkeratinisation, skin microbiome dysbiosis and local immuno-inflammation. Recent key studies have highlighted a better understanding of the important role of Cutibacterium acnes (C. acnes) in the development of acne. Three major findings in the last decade include: (1) the ability of C. acnes to self-organize in a biofilm associated with a more virulent activity, (2) the loss of the C. acnes phylotype diversity and (3) the central role of the Th17 pathway in acne inflammation. Indeed, there is a close link between C. acnes and the activation of the Th17 immuno-inflammatory pathway at the initiation of acne development. These mechanisms are directly linked to the loss of C. acnes phylotype diversity during acne, with a predominance of the pro-pathogenic phylotype IA1. This specifically contributes to the induction of the Th17-mediated immuno-inflammatory response involving skin cells, such as keratinocytes, monocytes and sebocytes. These advancements have led to new insights into the underlying mechanisms which can be harnessed to develop novel treatments and diagnostic biomarkers. A major disadvantage of traditional treatment with topical antibiotics is that they induce cutaneous dysbiosis and antimicrobial resistance. Thus, future treatments would no longer aim to 'kill' C. acnes, but to maintain the skin microbiota balance allowing for tissue homeostasis, specifically, the restoration of C. acnes phylotype diversity. Here, we provide an overview of some of the key processes involved in the pathogenesis of acne, with a focus on the prominent role of C. acnes and the Th17-inflammatory pathways involved.

Myrtus communis and Celastrol enriched plant cell culture extracts control together the pivotal role of Cutibacterium acnes and inflammatory pathways in acne

INTRODUCTION

Acne is a multifactorial inflammatory disease of the pilosebaceous unit in which Cutibacterium acnes is one of the main triggers. A strong predominance of C. acnes phylotype IA1 is present in acne skin with higher biofilm organization and virulence, promoting local immuno-inflammation, especially the Th17 pathway.

OBJECTIVES

We evaluated the single and combined pharmacological properties of the plant extracts, Myrtus communis (Myrtacine®) and Celastrol enriched plant cell culture (CEE) extracts on the C. acnes/Th17 pathway.

METHODS

The effect of Myrtacine® on the virulence of C. acnes phylotype IA1 was quantified according to the expression of several related genes. The activity of Myrtacine® and CEE on the inflammatory cascade was assessed using monocytes-derived dendritic cells (Mo-DC) stimulated with membranes or biofilms of the C. acnes phylotype IA1. Finally, the effect of CEE on the Th17 pathway was studied using C. acnes stimulated sebocyte 2D cultures and 3D skin tissue models containing preactivated Th17 cells.

RESULTS

Myrtacine® had an anti-virulence effect, evident as a significant and strong inhibition of the expression of several virulence factor genes by 60%-95% compared to untreated controls. Myrtacine® and CEE significantly inhibited proinflammatory cytokine (IL-6, IL-8, IL-12p40 and TNF-α) production by Mo-DC in response to C. acnes phylotype IA1. Interestingly, these two ingredients resulted in synergistic inhibition of most cytokines when used in combination. Finally, we demonstrated an inhibitory effect of CEE, in solution or formulated at 0.3%, specifically on IL-17 release by Th17 lymphocytes in a C. acnes-stimulated sebocyte 2D cultures and by Th17-lymphocytes integrated in a 3D skin models.

CONCLUSIONS

2D and 3D models were developed to represent relevant and specific pathways involved in acne. Myrtacine® and CEE were shown to alter one or more of these pathways, indicating their potential beneficial effects on this disease.

Minimum Contact Time of 1.25%, 2.5%, 5%, and 10% Benzoyl Peroxide for a Bactericidal Effect Against Cutibacterium acnes

Purpose

Benzoyl peroxide (BPO) is an effective acne treatment and has been used as a cleanser and short contact therapy. However, data on the minimum contact time of BPO needed to kill Cutibacterium acnes are lacking. Thus, the aim of this study was to determine the minimum contact time of commonly used BPO concentrations for bactericidal effects on C. acnes.

Materials and Methods

An in vitro experimental study of clinically isolated C. acnes was performed to determine the minimal inhibitory concentration (MIC) of BPO using the broth microdilution method. Subsequently, the minimum contact times of various concentrations of BPO were evaluated, and their bactericidal effects were assessed by the plate count method.

Results

The median MIC of BPO was 9375 µg/mL, which did not significantly differ between antibiotic-resistant and nonresistant C. acnes. The minimum contact time of BPO with C. acnes was significantly different among the BPO concentrations. For bactericidal activity against all isolates, 1.25%, 2.5%, 5%, and 10% BPO required 60 min, 15 min, 30 sec, and 30 sec, respectively.

Conclusion

BPO demonstrated bactericidal activity against both antibiotic-resistant and antibiotic-susceptible C. acnes. The in vitro contact time needed to kill C. acnes was almost immediate with 5% or more BPO, but ≤ 2.5% BPO required longer contact times for bactericidal effects.

Broad spectrum in vitro microbicidal activity of benzoyl peroxide against microorganisms related to cutaneous diseases

The in vitro microbicidal activity of benzoyl peroxide against Cutibacterium acnes, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Malassezia furfur, Malassezia restricta, and Malassezia globosa was investigated. These strains were incubated for 1 h in the presence of 0.25, 0.5, 1, or 2 mmol/L benzoyl peroxide in phosphate buffered saline supplemented with 0.1% glycerol and 2% Tween 80. After exposure to benzoyl peroxide, counts of viable Gram-positive bacteria and fungi were markedly decreased, whereas counts of Gram-negative bacteria were unchanged. Transmission electron microscopy images showed a decrease in electron density and the destruction of C. acnes and M. restricta cell walls after exposure to 2 mmol/L benzoyl peroxide. In conclusion, this study showed that benzoyl peroxide has a potent and rapid microbicidal activity against Gram-positive bacteria and fungi that are associated with various cutaneous diseases. This suggests that the direct destruction of bacterial cell walls by benzoyl peroxide is an essential mechanism of its rapid and potent microbicidal activity against microorganisms.

Novel Topical Application of a Postbiotic, LactoSporin®, in Mild to Moderate Acne: A Randomized, Comparative Clinical Study to Evaluate its Efficacy, Tolerability and Safety

Acne vulgaris is a common skin disorder of pilosebaceous units. The therapy for mild-to-moderate acne includes topical antibiotics, benzoyl peroxide and retinoids. In this open-label, randomized monocentric study, we compared the efficacy of LactoSporin® 2% w/w cream with benzoyl peroxide in 64 male and female subjects with mild-to-moderate acne for three weeks. The efficacy parameters were evaluated based on the dermatologist visual assessment and instrumental measurements using Sebumeter® MPA580, Antera 3DTM and VISIA CR 2.2 and subject self-assessment questionnaires. Adverse events were recorded throughout the study period. In order to understand the mechanism of action and properties of LactoSporin, the pH stability, thermostability, antimicrobial activity and 5-alpha reductase activity were evaluated in vitro. A significant improvement was observed in the dermatological assessment of closed comedones (p < 0.0001), open comedones (p = 0.0069) and papules count (p < 0.0001) in comparison to the baseline in both LactoSporin and benzoyl peroxide groups. The antera analysis showed significant improvement in redness (p < 0.0001) and elevation (p < 0.0001) (small and medium) in both the treatment groups. The sebumeter analysis showed a significant decrease in sebaceous secretion (p < 0.0001) for LactoSporin, which resulted in reduced oiliness, pimples, acne spots and redness around the acne spot. The product was found to be safe without any irritancy. LactoSporin was stable at an acidic pH and temperature range of 70 to 90 °C, with antimicrobial activity against various pathogenic bacteria, including Cutibacterium acnes. It was also a potent inhibitor of 5-alpha reductase activity. Thus, it can be concluded that the efficacy of LactoSporin is equivalent to benzoyl peroxide in the treatment of mild-to-moderate acne lesions and better than benzoyl peroxide for reducing the sebaceous secretion and oily, greasy nature of the skin, implying its efficacy in other sebohorriec conditions.

Lactobacillus paraplantarum THG-G10 as a potential anti-acne agent with anti-bacterial and anti-inflammatory activities

Cutibacterium acnes (formerly Propionibacterium acnes) is the main bacterium targeted for the prevention and medical treatment of acne vulgaris. Lactic acid bacteria (LAB) are a group of microorganisms classified by their ability to produce lactic acid through fermentation. Although the activities of LAB have been studied, their potential anti-acne effects are not well known. Here, Lactobacillus paraplantarum THG-G10, which has anti-bacterial activity against C. acnes, was isolated from traditional Kimchi in Republic of Korea. The anti-acne effects of dried cell-free supernatant of L. paraplantarum THG-G10 (DC-G10) were evaluated by determining its anti-microbial and anti-inflammatory activities. Anti-microbial activity was examined by a broth dilution assay: 25 mg/ml of DC-G10 inhibited the growth of C. acnes KCTC 5012 and KACC 1194; salicylic acid and benzoyl peroxide for acne treatment inhibited the growth of C. acnes KCTC 5012 and KACC 11946 at concentrations of 1.25 and 7.5 mg/ml, respectively; and tea tree oil inhibited the growth of C. acnes KCTC 5012 but not the growth of C. acnes KACC 11946 at 50 mg/ml. Anti-inflammatory activity was evaluated by a nitric oxide (NO) assay: only DC-G10 and ascorbic acid reduced LPS-induced NO production in RAW 264.7 cells in a dose-dependent manner. In addition, the toxicities of erythromycin, salicylic acid, benzoyl peroxide, tea tree oil, and DC-G10 were examined in HaCaT cells and normal human dermal fibroblasts (NHDFs). In these cells, the cytotoxic effects of DC-G10 were weaker than the effects of erythromycin, benzoyl peroxide, and ascorbic acid. Furthermore, scanning electron microscopy revealed that DC-G10 induces deleterious morphological changes in the bacterial cell membrane. These results demonstrate that DC-G10 may be an effective and safe treatment for acne vulgaris.

An update on formulation strategies of benzoyl peroxide in efficient acne therapy with special focus on minimizing undesired effects

Benzoyl peroxide (BPO) in the form of over the counter monotherapeutics or prescription-only combinations is a key component of topical acne therapy, but its unfavourable side effect profile reduces the therapeutic value of this compound. Various galenic approaches have been pursued to resolve this ambivalence, but only a few have managed to enter the market. This article aims to give a comprehensive overview of the published experimental vehicle systems and to identify the fundamental rationales. With regard to the formulation, an increase in the tolerability of BPO can essentially be achieved by combining BPO with re-fattening and moisturizing substances, by incorporating it and controlling its release, as well as by targeted deposition of the active ingredient at the site of action, i.e. drug targeting. Recently, novel particulate formulations have been proposed that combine several of these design principles and are expected to bring new developments in this dynamic field of research.

In vitro Antimicrobial Activity of Acne Drugs Against Skin-Associated Bacteria

Acne is a common skin affliction that involves excess sebum production and modified lipid composition, duct blockage, colonization by bacteria, and inflammation. Acne drugs target one or more of these steps, with antibiotics commonly used to treat the microbial infection for moderate to severe cases. Whilst a number of other acne therapies are purported to possess antimicrobial activity, this has been poorly documented in many cases. We conducted a comparative analysis of the activity of common topical acne drugs against the principal etiological agent associated with acne: the aerotolerant anaerobic Gram-positive organism Propionibacterium acnes (recently renamed as Cutibacterium acnes). We also assessed their impact on other bacteria that could also be affected by topical treatments, including both antibiotic-sensitive and antibiotic-resistant strains, using broth microdilution assay conditions. Drugs designated specifically as antibiotics had the greatest potency, but lost activity against resistant strains. The non-antibiotic acne agents did possess widespread antimicrobial activity, including against resistant strains, but at substantially higher concentrations. Hence, the antimicrobial activity of non-antibiotic acne agents may provide protection against a background of increased drug-resistant bacteria.

The microbiome in preadolescent acne: Assessment and prospective analysis of the influence of benzoyl peroxide

BACKGROUND/OBJECTIVES

The pathogenesis of preadolescent acne has not been well studied, and it is uncertain if Cutibacterium acnes is a predominant organism in the microbiome in this age group. The aim of this study was to analyze the microbiome of preadolescent females and to assess whether benzoyl peroxide impacts the microbiome.

METHODS

The study enrolled girls, aged 7-12 years, with evidence of at least six acne lesions who had not been previously treated. Participants' skin surface of forehead, cheeks, nose, chin, left retroauricular crease, and extruded contents of a comedonal lesion were sampled at baseline. Participants used benzoyl peroxide 4% wash for 6-8 weeks and returned for skin surface sampling and extraction collection. Microbiome analysis was performed using 16S ribosomal RNA gene amplicon sequencing on all swab and lesional extraction samples.

RESULTS

Fifty-one participants were enrolled with a median IGA score of 2 (mild). Changes in microbiome diversity were associated with increasing age and number of acne lesions (P = 0.001). C. acnes had higher abundances on forehead and nose, as opposed to cheeks and chin (P = 0.009). Bacterial diversity (alpha diversity) of the skin microbiome was comparable between preadolescent at baseline and after treatment with benzoyl peroxide.

CONCLUSION

This is the first large assessment characterizing female acne microbiome in early and late preadolescence. Results show that preadolescent acne can vary in its microbial profile, reflecting surrounding changes associated with the onset of puberty. Although benzoyl peroxide use was associated with decreased acne counts, its effect on microbial diversity was not demonstrated in our study.

Clinical efficacy and safety of benzoyl peroxide for acne vulgaris: Comparison between Japanese and Western patients

Benzoyl peroxide (BPO) has been well established as a common medication for acne vulgaris in many countries (e.g. in Europe and the USA), where clinical data have been accumulated over a long time. In Japan, the use of BPO for acne treatment was approved in 2014, and the results of clinical trials in Japanese patients have recently been reported. This review compares clinical study results between Japanese and Western patients. Clinical studies that had been performed in Western countries were searched on the basis of the criteria, double-blind studies of BPO monotherapy and comparison with a vehicle group. Two reports of Japanese studies were also selected by using the same criteria. Efficacy was assessed by comparing the mean difference between the BPO and the vehicle groups for reduction rate in the number of lesions from baseline, and there were no differences between Japanese and Western patients. Safety assessment also showed that the incidence of adverse events was higher in Japanese patients than in Western patients, but the characteristics of the adverse events were not different. Therefore, we conclude that there are no significant differences in the efficacy and safety of BPO between these patient populations. The efficacy and safety of long-term use in Japanese patients are also expected to be applicable to those in Western patients.

Twelve-week, multicenter, placebo-controlled, randomized, double-blind, parallel-group, comparative phase II/III study of benzoyl peroxide gel in patients with acne vulgaris: A secondary publication

A placebo-controlled, randomized, double-blind, parallel-group, comparative, multicenter study was conducted to investigate the efficacy and safety of benzoyl peroxide (BPO) gel, administrated once daily for 12 weeks to Japanese patients with acne vulgaris. Efficacy was evaluated by counting all inflammatory and non-inflammatory lesions. Safety was evaluated based on adverse events, local skin tolerability scores and laboratory test values. All 609 subjects were randomly assigned to receive the study products (2.5% and 5% BPO and placebo), and 607 subjects were included in the full analysis set, 544 in the per protocol set and 609 in the safety analyses. The median rates of reduction from baseline to the last evaluation of the inflammatory lesion counts, the primary end-point, in the 2.5% and 5% BPO groups were 72.7% and 75.0%, respectively, and were significantly higher than that in the placebo group (41.7%). No deaths or other serious adverse events were observed. The incidences of adverse events in the 2.5% and 5% BPO groups were 56.4% and 58.8%, respectively; a higher incidence than in the placebo group, but there was no obvious difference between the 2.5% and 5% BPO groups. All adverse events were mild or moderate in severity. Most adverse events did not lead to study product discontinuation. The results suggested that both 2.5% and 5% BPO are useful for the treatment of acne vulgaris.

Open-label, randomized, multicenter, phase III study to evaluate the safety and efficacy of benzoyl peroxide gel in long-term use in patients with acne vulgaris: A secondary publication

An open‐label, randomized, multicenter study was conducted to evaluate the safety and efficacy of long‐term use of 2.5% and 5% benzoyl peroxide (BPO) gels administrated once daily for 52 weeks to Japanese patients with acne vulgaris. The efficacy of the study drugs was evaluated by counting inflammatory lesions and non‐inflammatory lesions. Safety was evaluated based on adverse events, local skin tolerability scores and laboratory test values. In total, 458 subjects were included in the efficacy and safety analyses. The total lesion count, the efficacy end‐point, was similarly changed both in the 2.5% and 5% BPO groups over the course of the study. The median rates of reduction from baseline to week 12 were approximately 65%. Thereafter, the counts were maintained at a reduced level without increasing until week 52. The median rates at week 52 were approximately 80%. Similar trends were observed for inflammatory and non‐inflammatory lesion counts. Bacteriological evaluation indicated similar distribution of the minimum inhibitory concentration of each of the antibacterial drugs against Propionibacterium acnes between the values at baseline and at week 52, suggesting that long‐term use did not result in changes in the drug sensitivity. The incidence of adverse events was 84.0% in the 2.5% BPO group and 87.2% in the 5% BPO group. Many of the adverse events occurred within the first month and were mild or moderate in severity and transient. The results suggest that both 2.5% and 5% BPO gels are effective and safe for long‐term treatment of patients with acne vulgaris.

In vitro antimicrobial activity of benzoyl peroxide against Propionibacterium acnes assessed by a novel susceptibility testing method

Benzoyl peroxide (BPO), a therapeutic agent for acne vulgaris, was assessed for in vitro antimicrobial activity against Propionibacterium acnes using a novel broth microdilution testing that improved BPO solubility. We searched for a suitable culture medium to measure the minimum inhibitory concentration (MIC) of BPO against P. acnes and finally found the Gifu anaerobic medium (GAM) broth supplemented with 0.1(v/v)% glycerol and 2(v/v)% Tween 80, in which BPO dissolved up to 1250 μg/mL and P. acnes grew well. The MICs and minimum bactericidal concentrations (MBCs) of BPO against 44 clinical isolates of P. acnes collected from Japanese patients with acne vulgaris were determined by our testing method using the supplemented GAM broth. The MICs of BPO were 128 or 256 μg/mL against all isolates of P. acnes regardless of susceptibility to nadifloxacin or clindamycin. The MBCs of BPO were also 128 or 256 μg/mL against the same isolates. Moreover, BPO at the MIC showed a rapid bactericidal activity against P. acnes ATCC11827 in time-kill assay. In conclusion, we could develop a novel assay for the MIC and MBC determinations of BPO against P. acnes, which is reliable and reproducible as a broth microdilution testing and the present results suggest that BPO has a potent bactericidal activity against P. acnes.

Treatment of acne in children

Acne is a common skin condition in adolescents. It is not uncommon in childhood and it persists into adulthood. A broad range of acne treatments are available and have been shown to be safe and effective in adolescents and adults. However, there is limited literature regarding acne treatment in childhood and its available therapeutic options. It seems reasonable to extrapolate findings of the various studies reported on treatment of acne in the adolescent and adult age group, with the exclusion of the use of tetracycline derivatives. As clinicians, we must be more familiar with the clinical presentation of acne and available treatment options in our younger patients. Early recognition of acne with prompt and appropriate initiation of therapy in childhood will help prevent severe scarring in children.

Antibacterial activity of long-chain polyunsaturated fatty acids against Propionibacterium acnes and Staphylococcus aureus

New compounds are needed to treat acne and superficial infections caused by Propionibacterium acnes and Staphylococcus aureus due to the reduced effectiveness of agents used at present. Long-chain polyunsaturated fatty acids (LC-PUFAs) are attracting attention as potential new topical treatments for Gram-positive infections due to their antimicrobial potency and anti-inflammatory properties. This present study aimed to investigate the antimicrobial effects of six LC-PUFAs against P. acnes and S. aureus to evaluate their potential to treat infections caused by these pathogens. Minimum inhibitory concentrations were determined against P. acnes and S. aureus, and the LC-PUFAs were found to inhibit bacterial growth at 32–1024 mg/L. Generally, P. acnes was more susceptible to the growth inhibitory actions of LC-PUFAs, but these compounds were bactericidal only for S. aureus. This is the first report of antibacterial activity attributed to 15-hydroxyeicosapentaenoic acid (15-OHEPA) and 15-hydroxyeicosatrienoic acid (HETrE), while the anti-P. acnes effects of the six LC-PUFAs used herein are novel observations. During exposure to the LC-PUFAs, S. aureus cells were killed within 15–30 min. Checkerboard assays demonstrated that the LC-PUFAs did not antagonise the antimicrobial potency of clinical agents used presently against P. acnes and S. aureus. However, importantly, synergistic interactions against S. aureus were detected for combinations of benzoyl peroxide with 15-OHEPA, dihomo-γ-linolenic acid (DGLA) and HETrE; and neomycin with 15-OHEPA, DGLA, eicosapentaenoic acid, γ-linolenic acid and HETrE. In conclusion, LC-PUFAs warrant further evaluation as possible new agents to treat skin infections caused by P. acnes and S. aureus, especially in synergistic combinations with antimicrobial agents already used clinically.

Practical considerations in acne treatment and the clinical impact of topical combination therapy

Acne vulgaris is a highly prevalent, multifactorial disease process affecting the pilosebaceous units of the dermis. The effects of acne are profound both physically and psychosocially across all age groups and ethnicities; therefore, prompt recognition and appropriate treatment are critical. Pharmacotherapeutic approaches range from simple monotherapy to multimodal treatments with a variety of topical and systemic agents. Optimal patient outcomes in acne management, however, are based both on treatment efficacy as well as overall patient satisfaction. In an effort to comprehensively address these key clinical considerations in acne management, we examine the diverse nature of acne patients, the factors in optimizing treatment outcomes, and the clinical impact of current medications, particularly topical combination therapy.

A randomized, single-blind comparison of topical clindamycin + benzoyl peroxide (Duac) and erythromycin + zinc acetate (Zineryt) in the treatment of mild to moderate facial acne vulgaris

BACKGROUND

Antibiotics are often combined with other agents to provide topical acne treatments that are effective against both inflammatory and non-inflammatory lesions and minimize the development of antibiotic resistance.

OBJECTIVES

To compare the clinical effectiveness of two combination treatments for facial acne: a ready mixed, once daily gel containing clindamycin phosphate (1%) plus benzoyl peroxide (5%) (CDP + BPO) and a twice daily solution of erythromycin (4%) plus zinc acetate (1.2%) (ERY + Zn).

METHODS/PATIENTS

In this assessor-blind, randomized study, 73 patients were treated with CDP + BPO once daily and 75 patients with ERY + Zn twice daily. The treatment period was 12 weeks and lesion counts and global improvement were assessed at weeks 1, 2, 4, 8 and 12.

RESULTS

CDP + BPO showed an earlier onset of action with a faster significant reduction in total lesion counts than ERY + Zn. The proportion of patients with at least a 30% improvement in non-inflammatory lesions at week 1 was 31.5% for CDP + BPO and 17.3% for ERY + Zn; the corresponding percentages for inflammatory lesions were 39.7% and 29.3%. A difference was also observed at week 2 (53.4% vs. 36.0% for non-inflammatory lesions and 72.6% vs. 53.3% for inflammatory lesions). The trend in favour of CDP + BPO, although less marked, continued to the end of the study, with reductions in the total lesion count at endpoint of 69.8% for CDP + BPO group and 64.5% for ERY + Zn group. Both treatments were well tolerated.

CONCLUSIONS

CDP + BPO and ERY + Zn are effective treatments for acne but CDP + BPO has an earlier onset of action that should improve patient compliance.

A randomized, double-blind comparison of a clindamycin phosphate/benzoyl peroxide gel formulation and a matching clindamycin gel with respect to microbiologic activity and clinical efficacy in the topical treatment of acne vulgaris

BACKGROUND

One approach to suppressing the overgrowth of antibiotic-resistant bacteria is to develop combination products composed of active constituents with complementary but distinct mechanisms of antibacterial action.

OBJECTIVE

The purpose of this study was to compare the antimicrobial and clinical efficacy and tolerability of clindamycin phosphate 1%/benzoyl peroxide 5% gel formulation with matching clindamycin 1% gel in the treatment of acne vulgaris.

METHODS

This 16-week, single-center, double-blind, randomized, parallel-group study compared the combination gel with clindamycin monotherapy applied BID in patients 13 to 30 years of age with mild to moderate acne and facial Propionibacterium acnes counts > or = 10(4) colony-forming units per square centimeter of skin.

RESULTS

Seventy-nine patients were enrolled and randomly assigned to receive the combination gel (n = 40) or clindamycin monotherapy (n = 39). Seventy patients (50 males, 20 females; mean age, 18.2 years) were included in the intent-to-treat group. The combination gel treatment produced significantly greater reductions (P < or = 0.046) from baseline in total lesion counts and in numbers of inflammatory lesions and comedones compared with clindamycin monotherapy. Greater reductions in the severity of acne also were observed in the physician's and patient's Clinical Global Improvement scale scores and in other secondary efficacy measurements. Reductions in clindamycin-resistant P acnes counts were observed relative to baseline in the combination gel group; in contrast, P acnes counts increased by >1,600% in the clindamycin monotherapy group at week 16 (P = 0.018 vs combination gel). Reductions in inflammatory (r2 = 0.31; P = 0.016) and total (r2 = 0.28; P = 0.027) lesions were correlated with decreases in clindamycin-resistant bacteria. Also, significant correlations were observed between the percent change from baseline in total lesion counts (r2 = 0.44; P < 0.001) and comedo counts (r2 = 0.50; P < 0.001) and the log10 change from baseline in total P acnes counts.

CONCLUSIONS

The total P acnes count (P = 0.002) and the clindamycin-resistant P acnes count (P = 0.018) were significantly reduced after 16 weeks of treatment with combination gel compared with clindamycin monotherapy. These reductions in total P acnes and clindamycin-resistant P acnes counts correlated with reductions in total acne lesions.

Comparison of the efficacy and safety of a combination topical gel formulation of benzoyl peroxide and clindamycin with benzoyl peroxide, clindamycin and vehicle gel in the treatments of acne vulgaris

BACKGROUND

Topical clindamycin and benzoyl peroxide have each demonstrated clinical efficacy in the treatment of acne vulgaris. When used in combination, they promise greater efficacy than either individual agent used alone and the combined use of benzoyl peroxide with topical antibacterial has been shown to decrease the emergence of antibacterial resistant species.

OBJECTIVE

The objective was to determine the efficacy and safety of a combination benzoyl peroxide plus clindamycin in a gel formulation compared with each of its 2 active constituents in gel vehicle, and gel vehicle given alone in the treatment of acne vulgaris.

METHODS

In this 10-week, multicenter, double-blind trial, 480 patients with moderate to moderately severe acne were randomized to receive twice-daily treatment with 5% benzoyl peroxide plus 1% clindamycin, 5% benzoyl peroxide, 1% clindamycin, or vehicle.

RESULTS

Significantly greater reductions in the number of inflammatory and total lesions were demonstrated in patients using combination therapy compared with those using any of its 3 individual components. Likewise, both physicians' and patients' global evaluations showed significantly greater improvements with the combination therapy than with its individual components. The most frequent adverse effect, dry skin, occurred to a similar extent in the combination and benzoyl peroxide treatment groups.

CONCLUSION

The improved efficacy obtained with the combination therapy was accompanied by a tolerability profile similar to that of benzoyl peroxide alone, making this new combination product an alternative antimicrobial therapy for acne vulgaris.

The efficacy and safety of a combination benzoyl peroxide/clindamycin topical gel compared with benzoyl peroxide alone and a benzoyl peroxide/erythromycin combination product

BACKGROUND

Topical clindamycin and benzoyl peroxide have each demonstrated clinical efficacy in the treatment of acne vulgaris. When used in tandem, they promise greater efficacy than either individual agent through their antibacterial and anti-inflammatory effects.

OBJECTIVE

To determine the efficacy and safety of combination benzoyl peroxide/ clindamycin compared with benzoyl peroxide or benzoyl peroxide/erythromycin in the treatment of acne.

METHODS

In this randomized, 10-week, multicenter, single-blind trial, 492 patients with moderate to moderately severe acne were treated twice daily with 5% benzoyl peroxide/1% clindamycin, 5% benzoyl peroxide, or 5% benzoyl peroxide/3% erythromycin and assessed every 2 weeks.

RESULTS

Compared with benzoyl peroxide, benzoyl peroxide/clindamycin demonstrated significantly greater reductions in inflammatory lesions (p = 0.04) and significantly greater overall improvement as assessed by physicians (p < or = 0.04) and patients (p < 0.001). Benzoyl peroxide/clindamycin demonstrated a nonsignificant trend for greater efficacy compared to benzoyl peroxide/erythromycin. Dry skin was the most frequent (< or = 7.3%) adverse event with all three therapies.

CONCLUSION

Benzoyl peroxide/clindamycin demonstrated improved efficacy and similar tolerability; to benzoyl peroxide used alone and was similar to benzoyl peroxide/ erythromycin, making this combination product an effective alternative antimicrobial therapy for acne.

Effects of benzoyl peroxide on lipogenesis in sebaceous glands using an animal model

BACKGROUND

Benzoyl peroxide is the most widely used topical agent for acne since the 1960s. Concomitant treatment of benzoyl peroxide with oral, or topical antibiotics diminishes the multiplication of antibiotic-resistant strains of Propionibacteria acnes. Besides being antibacterial, the chemical also functions as a peeling agent, has comedolytic activity, reduces free fatty acid levels, and is touted to be sebosuppressive.

OBJECTIVE

The purpose was to determine the ability of topically applied benzoyl peroxide to suppress lipogenesis of the sebaceous glands.

METHODS

The data were obtained employing an animal model for human sebaceous glands, namely, the flank organs of female golden Syrian hamsters.

RESULTS

Our results reveal no inhibition of lipogenesis in sebaceous glands by topical application of benzoyl peroxide.

CONCLUSION

Despite many functions beneficial in acne therapy, benzoyl peroxide does not possess sebosuppressive capabilities. With the advent of water-soluble organic peroxides revealing similar antimicrobial activity to benzoyl peroxide, all therapeutic parameters (save for sebosuppression) will need to be assessed to weigh the benefits of these second-generation acne-fighting peroxides.

Digital fluorescence photography can assess the suppressive effect of benzoyl peroxide on Propionibacterium acnes

BACKGROUND

Porphyrins produced by Propionibacterium acnes exhibit an orange-red fluorescence under UVA light. The amount of fluorescence can be estimated by digital fluorescence photography.

OBJECTIVE

We thought that digital fluorescence photography would be a quicker and simpler method than bacteriologic culture to demonstrate depopulation of P acnes in sebaceous follicles. We used benzoyl peroxide to bring about rapid suppression of P acnes.

METHODS

Benzoyl peroxide 10% was applied twice daily for 7 days to the faces of 9 subjects. Five subjects were untreated controls. Digital fluorescence photographs of cheek and nose, and scrub samples for quantitative recovery of P acnes from the cheek were taken at baseline, day 3, day 7 (end of treatment), and day 16 (regression phase).

RESULTS

The effect of benzoyl peroxide against P acnes was clearly demonstrated both by culture and by fluorescence photography after only 3 days. Image analysis of porphyrin fluorescence correlated well with the decrease in P acnes density from scrub cultures. No further decrease was observed at day 7 (end of therapy). Ten days later there was a return to baseline values, although in some subjects these remained lower.

CONCLUSION

Digital fluorescence photography is a reliable, fast, and easy screening technique to demonstrate the suppressive effect of topical antibacterial agents on P acnes.

Synthesis and antibacterial evaluation of novel water-soluble organic peroxides

A set of new water-soluble organic peroxides has been synthesized and evaluated for in vitro antibacterial activity as part of an effort to develop new antibacterial agents for the treatment of acne vulgaris. The water solubility of these new dialkyl peroxides and peroxyesters was achieved by incorporating either a quaternary ammonium group or a polyethylene glycol moiety. These peroxides are effective against both gram-positive and gram-negative bacteria and have a prolonged activity compared to that of benzoyl peroxide and other peroxide-type antiseptic agents. Among them 4-[[(tert-butylperoxy)carbonyl]benzyl]triethylammonium chloride and [10-(tert-butylperoxy)decyl]trimethylammonium bromide have the broadest antimicrobial spectrums. We have shown that the oxidizing properties of the dioxy group of these compounds are responsible for their antibacterial activities.

Utility of topical benzoyl peroxide for prevention of surgical skin wound infection

BACKGROUND

Benzoyl peroxide is a powerful oxiding agent with broad spectrum germicidal activity and good liposolubility. Therefore, it may represent a good agent for prevention of wound infection in areas with high density of sebaceous glands.

OBJECTIVE

The aim of this study was to analyze the effectiveness of topical benzoyl peroxidase gel for prevention of surgical skin wound infections in the centrofacial area.

METHODS

A prospective study was performed on 673 patients. The patients were divided into two groups. Group A, 335 patients, was given no antibacterial prophylaxis. In group B, 338 patients, prophylactic medication with a gel containing 10% benzoyl peroxide was performed once a day for the 7 days before the surgery.

RESULTS

Thirteen of 673 patients had wound infections (1.93%). Eleven of these 13 patients were in group A (3.24%) and two were in group B (0.59%) (P < .01).

CONCLUSIONS

Topical benzoyl peroxide is an efficacious, harmless, and inexpensive agent for prevention of wound infections in seborrheic regions.