Transdermal Penetration of Topical Drugs Used in the Treatment of Acne

Individual sol-gel microencapsulation of benzoyl peroxide and tretinoin enables controlled release onto the skin

A combination of benzoyl peroxide (BPO) and tretinoin is recommended for treating acne; however, concurrent administration can be irritating, and coformulation is prevented by BPO-mediated oxidation of tretinoin. In rosacea, benzoyl peroxide has been shown to be efficacious; however, its use has been limited by poor tolerability. To overcome these limitations, the active ingredients can be encapsulated within silica microcapsules. The US Food and Drug Administration has approved 2 products using this technology, a combination of encapsulated benzoyl peroxide and encapsulated tretinoin product for acne vulgaris and encapsulated benzoyl peroxide to treat inflammatory lesions in rosacea. The active ingredients are released through small channels in the silica shell, gradually releasing the active ingredients to the skin. This study describes the stability and release profiles of encapsulated tretinoin and encapsulated benzoyl peroxide from the silica shell in physiologically relevant conditions and provides differentiation from traditional formulations.

Combined Cutaneous Therapy Using Biocompatible Metal-Organic Frameworks

Combined therapies emerge as an interesting tool to overcome limitations of traditional pharmacological treatments (efficiency, side effects). Among other materials, metal-organic frameworks (MOFs) offer versatilities for the accommodation of multiple and complementary active pharmaceutical ingredients (APIs): accessible large porosity, availability of functionalization sites, and biocompatibility. Here, we propose topical patches based on water-stable and biosafe Fe carboxylate MOFs (MIL-100 and MIL-127), the biopolymer polyvinyl alcohol (PVA) and two co-encapsulated drugs used in skin disorders (azelaic acid (AzA) as antibiotic, and nicotinamide (Nic) as anti-inflammatory), in order to develop an advanced cutaneous combined therapy. Exceptional MOF drug contents were reached (total amount 77.4 and 48.1 wt.% for MIL-100 and MIL-127, respectively), while an almost complete release of both drugs was achieved after 24 h, adapted to cutaneous delivery. The prepared cutaneous PVA-MOF formulations are safe and maintain the high drug-loading capacity (total drug content of 38.8 and 24.2 wt.% for MIL-100 and MIL-127, respectively), while allowing a controlled delivery of their cargoes, permeating through the skin to the active target sites. The total amount of drug retained or diffused through the skin is within the range (Nic), or even better (AzA) than commercial formulations. The presented results make these drug combined formulations promising candidates for new cutaneous devices for skin treatment.

Recent Advances Regarding the Therapeutic Potential of Adapalene

Adapalene (ADP) is a representative of the third retinoids generation and successfully used in first-line acne treatment. ADP binds to retinoic acid nuclear receptors. The comedolytic, anti-inflammatory, antiproliferative, and immunomodulatory are the known ADP effects. Its safety profile is an advantage over other retinoids. ADP recently was found to be effective in the treatment of several dermatological diseases and photoaging besides the utility in the treatment of acne vulgaris. New biological effects of adapalene with therapeutic potential are highlighted in this review paper. Thus, adapalene could be a valuable therapeutic drug into the treatment of several types of cancer. Additionally, some neurodegenerative diseases could be treated with a suitable formulation for intravenous administration. The antibacterial activity against methicillin-resistant Staphylococcus aureus of an analogue of ADP has been proven. In different therapeutic schemes, ADP is more effective in combination with other active substances. New topical combinations with adapalene include ketoconazole (antifungal), mometasone furoate (anti-inflammatory corticosteroid), nadifloxacin (fluoroquinolone), and alfa and beta hydroxy acids. Combination with oral drugs is a new trend that enhances the properties of topical formulations with adapalene. Several studies have investigated the effects of ADP in co-administration with azithromycin, doxycycline, faropenem, isotretinoin, and valganciclovir. Innovative formulations of ADP also aim to achieve a better bioavailability, increased efficacy, and reduced side effects. In this review, we have highlighted the current studies on adapalene regarding biological effects useful in various treatment types. Adapalene has not been exploited yet to its full biological potential.

Structure elucidation of silica-based core-shell microencapsulated drugs for topical applications by cryogenic scanning electron microscopy

We present here a technology to microencapsulate drugs by the sol-gel process, and cryo-SEM methodology that allows the nanostructural characterization of the formed capsules in their native state without any artifacts, related to their drying prior to imaging. The methodology utilizes three signals generated by the electron beam scanning the specimen: Secondary electrons, backscattered electrons, and x-rays. The first gives topographical information of the fracture-surface of the thermally-fixed specimen, the second gives contrast between elements of different atomic numbers, and the third allows the identification of those elements. Combined, the three signals provide full microstructural characterization of the studied specimen. Using this methodology, we were able to demonstrate that the sol-gel technology does indeed enable the encapsulation of two hydrophobic active molecules with a silica shell. This technology allows the active ingredient in the drug product to slowly migrate from the microcapsule onto the skin, thus obtaining the desired effect with minimal side-effects, as was exhibited in several clinical studies. The successful application of the cryo-SEM methodology in this case, demonstrates that it can be used to characterize a wide range of liquid-phase suspensions, in their native state, with minimal specimen preparation or imaging artifacts.

From pathogenesis of acne vulgaris to anti-acne agents

Acne vulgaris is a cutaneous chronic inflammatory disorder with complex pathogenesis. Four factors play vital roles in acne pathophysiology: hyperseborrhea and dysseborrhea, altered keratinization of the pilosebaceous duct, Cutibacterium acnes (C. acnes) and inflammation. The main hormones responsible for the development of acne vulgaris include androgens, insulin and insulin-like growth factor-1. Other factors involved in this process are corticotropin-releasing hormone, α-melanocyte-stimulating hormone and substance P. Wnt/β-catenin signaling pathway, phosphoinositide 3-kinase (PI3K)/Akt pathway, mitogen-activated protein kinase pathway, adenosine 5'-monophosphate-activated protein kinase pathway and nuclear factor kappa B pathway participate in the modulation of sebocyte, keratinocyte and inflammatory cell (e.g. lymphocytes, monocytes, macrophages, neutrophils) activity. Among all the triggers and pathways mentioned above, IGF-1-induced PI3K/Akt/Forkhead box protein O1/mammalian target of rapamycin (mTOR) C1 pathway is the most important signaling responsible for acne pathogenesis. Commonly used anti-acne agents include retinoids, benzoyl peroxide, antibiotics and hormonal agents (e.g. spironolactone, combination oral contraceptive and flutamide). New approaches including peroxisome proliferator-activated receptor γ modifier, melanocortin receptor antagonists, epigallocatechin-3-gallate, metformin, olumacostat glasaretil, stearoyl-CoA desaturase inhibitor omiganan pentahydrochloride, K_DPT, afamelanotide, apremilast and biologics have been developed as promising treatments for acne vulgaris. Although these anti-acne agents have various pharmacological effects against the diverse pathogenesis of acne, all of them have a synergistic mode of action, the attenuation of Akt/mTORC1 signaling and enhancement of p53 signal transduction. In addition to drug therapy, diet with no hyperglycemic carbohydrates, no milk and dairy products is also beneficial for treatment of acne.

Lack of pregnancy warnings on over-the-counter dermatologic products containing potentially harmful hydroquinone

OBJECTIVE

To determine the presence of pregnancy warnings on over-the-counter (OTC) dermatologic products with hydroquinone, a potentially harmful ingredient.

STUDY DESIGN

Data were obtained from the Food and Drug Administration National Drug Code Directory and Label Repository to identify OTC dermatologic products containing hydroquinone. Products were stratified based on pregnancy or general warning presence (WP) or absence (WA). Product characteristics were compared between groups: hydroquinone concentration, presence of external packaging, indication and warning statements.

RESULTS

Of the 112 products studied, 21 had a pregnancy warning and 3 included a general warning against use: WP (n=24) and WA (n=88) group. External packaging was more prevalent in the WP group compared to WA (62.5% vs 29.5%, P=0.004).

CONCLUSIONS

Majority of OTC dermatologic products containing hydroquinone did not have a pregnancy warning. This highlights the need for improved labeling and informs providers caring for pregnant women of OTC labeling limitations.

Treatment Modalities for Acne

Acne is a common inflammatory skin disease which affects the pilosebaceous units of the skin. It can have severe psychological effects and can leave the patient with severe skin scarring. There are four well-recognized pathological factors responsible for acne which is also the target for acne therapy. In this review, different treatment options are discussed, including topical (i.e., retinoids, and antibiotics) and systemic (i.e., retinoids, antibiotics, and hormonal) treatments. Since the general public has been showing an increasing interest in more natural and generally safer treatment options, the use of complementary and alternative medicines (CAM) for treating acne was also discussed. The use of physical therapies such as comedone extraction, cryoslush therapy, cryotherapy, electrocauterization, intralesional corticosteroids and optical treatments are also mentioned. Acne has been extensively researched with regards to the disease mechanism as well as treatment options. However, due to the increasing resistance of Propionibacterium acnes towards the available antibiotics, there is a need for new treatment methods. Additionally, the lack of necessary evidence on the efficacy of CAM therapies makes it necessary for researchers to investigate these treatment options further.

A consensus-based practical and daily guide for the treatment of acne patients

BACKGROUND

Many current guidelines provide detailed evidence-based recommendations for acne treatment.

OBJECTIVE

To create consensus-based, simple, easy-to-use algorithms for clinical acne treatment in daily office-based practice and to provide checklists to assist in determining why a patient may not have responded to treatment and what action to take.

METHODS

Existing treatment guidelines and consensus papers were reviewed. The information in them was extracted and simplified according to daily clinical practice needs using a consensus-based approach and based on the authors' clinical expertise.

RESULTS

As outcomes, separate simple algorithms are presented for the treatment of predominant comedonal, predominant papulopustular and nodular/conglobate acne. Patients with predominant comedonal acne should initially be treated with a topical retinoid, azelaic acid or salicylic acid. Fixed combination topicals are recommended for patients with predominant papulopustular acne with treatment tailored according to the severity of disease. Treatment recommendations for nodular/conglobate acne include oral isotretinoin or fixed combinations plus oral antibiotics in men, and these options may be supplemented with oral anti-androgenic hormonal therapy in women. Further decisions regarding treatment responses should be evaluated 8 weeks after treatment initiation in patients with predominant comedonal or papulopustular acne and 12 weeks after in those with nodular/conglobate acne. Maintenance therapy with a topical retinoid or azelaic acid should be commenced once a patient is clear or almost clear of their acne to prevent the disease from recurring. The principal explanations for lack of treatment response fall into 5 main categories: disease progression, non-drug-related reasons, drug-related reasons, poor adherence, and adverse events.

CONCLUSION

This practical guide provides dermatologists with treatment algorithms adapted to different clinical features of acne which are simple and easy to use in daily clinical practice. The checklists to establish the causes for a lack of treatment response and subsequent action to take will facilitate successful acne management.

Design of polymeric nanoparticles and its applications as drug delivery systems for acne treatment

OBJECTIVE

The aim of this study was to evaluate a formulation made of poly(lactide-co-glycolide) (PLGA) nanoparticles containing azelaic acid for potential acne treatment.

METHODS

Azelaic acid-loaded PLGA nanoparticles were prepared by spontaneous emulsification processes using poloxamer 188 as stabilizer. Several manufacturing parameters such as stirring rate, concentration of stabilizer and different recovery methods were investigated. Nanoparticles were evaluated in terms of size, zeta potential, encapsulation efficiency, release kinetics and permeation kinetics in vitro. Furthermore, in vitro toxicological studies were performed in Saccharomyces cerevisiae model.

RESULTS

The results showed that by adjusting some formulation conditions it was possible to obtain nanoparticles with high loading and a controlled drug release. Freeze-dried recovery altered the nanoparticles structure by enhancing porous structures and mannitol was required to control the mean particle size. The centrifugation recovery was found to be the best approach to nanoparticles recovery. Similar toxicity profiles were observed for both drug-free and azelaic acid-loaded nanoparticles, with concentration-dependent decreases in cell viability.

CONCLUSION

These results indicate a potential formulation for controlled release delivery of azelaic acid to the follicular unit.

[Acne therapy in pregnancy]

Acne should be treated during pregnancy to prevent worsening, scarring, secondary infection or psychological impairment of the mother. Safe products must be chosen. Systemic tetracycline, doxycycline, minocycline or isotretinoin can not be used. Topical benzoyl peroxide or topical azelaic acid are safe therapeutic options. According to the guidelines, systemic corticosteroids or systemic erythromycin (the latter not in lactation) can be employed beginning in the second trimester for severe flares of acne and should be started in cooperation with the patient's gynecologist. Oral zinc is another option, but not for longer than 3 months. Accessory cosmetic measures may be useful, including mechanical peeling or chemical peeling with glycolic or alpha-hydroxy-acids. In contrast, salicylic acid, trichloracetic acid or phenol peels should not be performed in pregnancy. Camouflage makeup can clearly lower the psychological stress.

Adapalene 0.1%/benzoyl peroxide 2.5% gel: a review of its use in the treatment of acne vulgaris in patients aged ≥ 12 years

Adapalene 0.1%/benzoyl peroxide 2.5% gel (Epiduo™, Tactuo™) is the only fixed-dose combination product available that combines a topical retinoid with benzoyl peroxide; it targets three of the four main pathophysiologic factors in acne. This article reviews the therapeutic efficacy and tolerability of topical adapalene 0.1%/benzoyl peroxide 2.5% gel in the treatment of patients aged ≥ 12 years with acne vulgaris, as well as summarizing its pharmacologic properties. In three 12-week trials in patients aged ≥ 12 years with moderate acne, success rates were significantly higher with adapalene 0.1%/benzoyl peroxide 2.5% gel than with adapalene 0.1% gel or benzoyl peroxide 2.5% gel alone, and combination therapy had an earlier onset of action. In addition, significantly greater reductions in total, inflammatory, and noninflammatory lesion counts were seen in patients receiving adapalene 0.1%/benzoyl peroxide 2.5% gel than in those receiving adapalene 0.1% gel or benzoyl peroxide 2.5% gel alone. Adapalene 0.1%/benzoyl peroxide 2.5% gel did not significantly differ from clindamycin 1%/benzoyl peroxide 5% gel in terms of the reduction in the inflammatory, noninflammatory, or total lesion counts in patients with mild to moderate acne, according to the results of a 12-week trial. Twelve-week studies showed that topical adapalene 0.1%/benzoyl peroxide 2.5% gel in combination with oral lymecycline was more effective than oral lymecycline alone in patients with moderate to severe acne, and topical adapalene 0.1%/benzoyl peroxide 2.5% gel in combination with oral doxycycline hyclate was more effective than oral doxycycline hyclate alone in patients with severe acne. In patients with severe acne who responded to 12 weeks' therapy with topical adapalene 0.1%/benzoyl peroxide 2.5% gel plus oral doxycycline hyclate or oral doxycycline hyclate alone, an additional 6 months' therapy with adapalene 0.1%/benzoyl peroxide 2.5% gel was more effective than vehicle gel at maintaining response, with further improvement seen in adapalene 0.1%/benzoyl peroxide 2.5% gel recipients. A noncomparative study also demonstrated the efficacy of 12 months' therapy with adapalene 0.1%/benzoyl peroxide 2.5% gel in patients with acne vulgaris. Topical adapalene 0.1%/benzoyl peroxide 2.5% gel was generally well tolerated in patients with acne. In 12-week trials, the most commonly occurring treatment-related adverse events included erythema, scaling, dryness, and stinging/burning; these dermatologic treatment-related adverse events were usually of mild to moderate severity, occurred early in the course of treatment, and resolved without residual effects. Topical adapalene 0.1%/benzoyl peroxide 2.5% gel was generally well tolerated in the longer term, with dry skin being the most commonly occurring treatment-related adverse event over 12 months of treatment. In conclusion, adapalene 0.1%/benzoyl peroxide 2.5% gel is a valuable agent for the first-line treatment of acne vulgaris.

Retinoids in the treatment of skin aging: an overview of clinical efficacy and safety

Aging of skin is an intricate biological process consisting of two types. While intrinsic or chronological aging is an inevitable process, photoaging involves the premature aging of skin occurring due to cumulative exposure to ultraviolet radiation. Chronological and photoaging both have clinically differentiable manifestations. Various natural and synthetic retinoids have been explored for the treatment of aging and many of them have shown histological and clinical improvement, but most of the studies have been carried out in patients presenting with photoaged skin. Amongst the retinoids, tretinoin possibly is the most potent and certainly the most widely investigated retinoid for photoaging therapy. Although retinoids show promise in the treatment of skin aging, irritant reactions such as burning, scaling or dermatitis associated with retinoid therapy limit their acceptance by patients. This problem is more prominent with tretinoin and tazarotene whereas other retinoids mainly represented by retinaldehyde and retinol are considerably less irritating. In order to minimize these side effects, various novel drug delivery systems have been developed. In particular, nanoparticles have shown a good potential in improving the stability, tolerability and efficacy of retinoids like tretinoin and retinol. However, more elaborate clinical studies are required to confirm their advantage in the delivery of topical retinoids.

Clindamycin/benzoyl peroxide gel (BenzaClin): a review of its use in the management of acne

Clindamycin 1%/benzoyl peroxide 5% (BenzaClin) is a combination gel indicated for use twice daily, or as directed by a physician, for the topical treatment of inflammatory and noninflammatory lesions of acne vulgaris. In well designed clinical trials in patients with mild to moderately severe acne, the efficacy of once- or twice-daily clindamycin/benzoyl peroxide in the reduction of inflammatory lesion counts was greater than that of benzoyl peroxide alone, clindamycin alone, or tretinoin plus clindamycin, and not significantly different from that of erythromycin/benzoyl peroxide. In the reduction of noninflammatory lesion counts, the efficacy of once- or twice-daily clindamycin/benzoyl peroxide was greater than that of clindamycin alone, but not significantly different to that observed with benzoyl peroxide, tretinoin plus clindamycin, or erythromycin/benzoyl peroxide. Clindamycin/benzoyl peroxide has a fairly rapid onset of action, with acne improvement usually recorded within 2-4 weeks. Despite widespread use, bacterial resistance is not associated with clindamycin/benzoyl peroxide. The product is generally well tolerated, and the main treatment-related adverse events in clinical trials were application-site dryness, irritation, peeling, and erythema. Thus, clindamycin/benzoyl peroxide is an effective and well tolerated option for the management of mild to moderately severe acne.

Novel Drug Delivery Systems: Potential in Improving Topical Delivery of Antiacne Agents

Acne is the most common cutaneous disorder of multifactorial origin with a prevalence of 70-85% in adolescents. The majority of the acne sufferers exhibit mild to moderate acne initially, which progresses to the severe form in certain cases. Topical therapy is employed as first-line treatment in mild acne, whereas for moderate and severe acne, systemic therapy is required in addition to topical therapy. Currently, several topical agents are available that affect at least one of the main pathogenetic factors responsible for the development of acne. Although topical therapy has an important position in acne treatment, side effects associated with various topical antiacne agents and the undesirable physicochemical characteristics of certain important agents like tretinoin and benzoyl peroxide affect their utility and patient compliance. Novel drug delivery strategies can play a pivotal role in improving the topical delivery of antiacne agents by enhancing their dermal localization with a concomitant reduction in their side effects. The current review emphasizes the potential of various novel drug delivery strategies like liposomes, niosomes, aspasomes, microsponges, microemulsions, hydrogels and solid lipid nanoparticles in optimizing and enhancing the topical delivery of antiacne agents.

The role of topical retinoids in the treatment of photoaging

Aging of the skin is a complex biological process which is influenced by the interaction of several intrinsic and extrinsic factors. Intrinsic or chronological aging is an inevitable, genetically programmed process, of unclear underlying mechanism, for which no prevention or effective treatment is currently available. Photoaging refers to the gross and microscopic cutaneous changes that are induced by cumulative exposure to UV radiation and are superimposed on the background of chronological aging. Although primarily an aesthetic problem with significant psychological effects, photoaging constitutes the background for the development of precancerous and cancerous skin lesions.Overwhelming clinical and histological evidence indicate that certain structural changes induced by excessive sun exposure can be reversed, to some extent, by the use of topical retinoids. A number of retinoid compounds, for example tretinoin, isotretinoin, retinaldehyde and tazarotene, have been employed for the treatment of photoaged skin, and demonstrate beneficial clinical and histological effects. Adverse effects have been limited to an irritant reaction of variable intensity presenting with dryness, scaling and erythema. Ongoing research will enhance our understanding of the molecular mechanisms that determine the effects of retinoids on photodamaged skin and contribute to the employment of new, more effective and less irritating retinoid compounds.

Comparison of azelaic acid and anthralin for the therapy of patchy alopecia areata: a pilot study

BACKGROUND

Although topical azelaic acid has been previously used for the treatment of alopecia, no controlled trials of azelaic acid for this condition have been conducted to date.

OBJECTIVE

The goal of this study was to determine the efficacy, tolerability, and safety of azelaic acid treatment in patients with patchy alopecia areata (AA) in comparison with anthralin (dithranol) treatment.

SUBJECTS AND METHODS

This study included 31 subjects with patchy AA who did not receive any treatment for at least 1 month prior to the study. Demographic and clinical characteristics of these subjects were recorded at baseline. Subjects were randomized to apply either 20% azelaic acid (15 subjects) or 0.5% anthralin (16 subjects) for 12 consecutive weeks. In a subsequent 8-week follow-up period no cream was applied. Two independent investigators performed an efficacy evaluation with clinical examination using a terminal hair regrowth score (RGS) with a scale ranging from 0 (inadequate response) to 2 (complete response) at week 20. Partial response was accepted as score 1.

RESULTS

Both groups were well matched for the relevant demographic and clinical indicators affecting treatment response at baseline. All subjects completed the trial. At week 20 the RGS was 1.27 +/- 0.9 in the azelaic acid group versus 1.37 +/- 0.8 in the anthralin group (p > 0.05). A complete response was observed in 53.3% of cases in the azelaic acid group (8 of 15) compared with 56.2% (9 of 16) in the anthralin group (p > 0.05). No serious adverse events were observed in either group during the study.

CONCLUSION

The present pilot study showed that the use of azelaic acid gave similar results to anthralin with regard to hair regrowth, and that it can be an effective topical therapy for patchy AA. More extensive trials are necessary, however, to reach a definitive conclusion.

Acne: Topical treatment

Acne vulgaris is a common skin disease, affecting about 70-80% of adolescents and young adults. It is a multifactorial disease of the pilosebaceous unit.(1) The influence of androgens at the onset of adolescence leads to an enlargement of the sebaceous gland and a rise in sebum production. Additional increased proliferation and altered differentiation of the follicular epithelium eventually blocks the pilosebaceous duct, leading to development of the microcomedo as the primary acne lesion. Concomitantly and subsequently, colonization with Propionibacterium acnes increases, followed by induction of inflammatory reactions from bacteria, ductal corneocytes, and sebaceous proinflammatory agents (Fig 1).(2-5)