The in vivo and in vitro anti-inflammatory activity of CD271: a new retinoid-like modulator of cell differentiation

Quantification and In Silico Toxicity Assessment of Tazarotene and its Impurities for a Quality and Safe Drug Product Development

Tazarotene is internationally accepted common name for ethyl 6-[(4,4-dimethylthiochroman-6-yl)ethynyl]nicotinate. It is a synthetic retinoid used for the topical treatment of mild to moderate plaque psoriasis, acne vulgaris and photo aging. To ensure the quality of drug product and drug substance, a LC-MS compatible UHPLC method was developed for quantification of drug and its related substances. Stationary phase with fused core particle technology is used for the separation of impurities. Limit of quantification and limit of detection of the method are 0.1 and 0.03%, respectively. Precision of the method for Tazarotene and all its related substances is less than 2.2% RSD. The correlation coefficient is >0.999. Accuracy of method is ranged from 95.3% to 107.0%. Application of this method in stability analysis has been demonstrated by analyzing stressed samples. Experimental design is used for the verification of robustness of the method. To ensure the safety, an in silico toxicity of the drug and its related substances were determined using TOPKAT and DEREK toxicity predictions Both UHPLC and in silico methods were validated as per the ICH Q2 and ICH M7 guidelines, which will enable a rapid product development of Tazarotene topical formulations while ensuring the safety and quality of product.

Treatment of Inflammatory Acne with a Combination Therapy with Lymecycline and Adapalene Followed by Maintenance Treatment with Adapalene

Oral antibiotics, especially tetracyclines, are commonly used to treat moderate to moderately severe acne vulgaris. There are hints suggesting that a combination treatment with oral tetracyclines and topical retinoids can cause a greater and prompter improvement of acne than monotherapy with tetracyclines. We evaluated the clinical activity of a 12-week combined therapy with oral lymecycline (300mg/day for 2 weeks and then 150mg/day) and topical adapalene (gel or cream) in 419 patients with inflammatory acne. A significant reduction in the number of acne lesions was noted at 4 and 12 weeks (P<0.0001). Thereafter, 400 patients underwent a maintenance treatment with adapalene alone for 12 weeks. At week 24 a relevant improvement of acne lesions still persisted (P<0.0001) in most patients. Only 16 patients relapsed and required additional use of oral lymecycline which proved again successful. No substantial differences were noted in the magnitude of clinical response between patients treated with adapalene gel and those treated with cream formulation. Treatment was well tolerated. Local adverse reactions occurred in 11.7 % of patients and resulted in premature discontinuation of treatment in 1.4 %. Systemic (gastrointestinal) untoward effects developed in 1.2 % of patients and caused treatment interruption in 0.7 % of cases. No serious adverse events occurred.

Adapalene inhibits the activity of cyclin-dependent kinase 2 in colorectal carcinoma

Cyclin-dependent kinase 2 (CDK2) has been reported to be overexpressed in human colorectal cancer; it is responsible for the G1‑to‑S‑phase transition in the cell cycle and its deregulation is a hallmark of cancer. The present study was the first to use idock, a free and open‑source protein‑ligand docking software developed by our group, to identify potential CDK2 inhibitors from 4,311 US Food and Drug Administration‑approved small molecular drugs with a re‑purposing strategy. Among the top compounds identified by idock score, nine were selected for further study. Among them, adapalene (ADA; CD271,6‑[3‑(1‑adamantyl)‑4‑methoxyphenyl]‑2‑naphtoic acid) exhibited the highest anti‑proliferative effects in LOVO and DLD1 human colon cancer cell lines. Consistent with the expected properties of CDK2 inhibitors, the present study demonstrated that ADA significantly increased the G1‑phase population and decreased the expression of CDK2, cyclin E and retinoblastoma protein (Rb), as well as the phosphorylation of CDK2 (on Thr‑160) and Rb (on Ser‑795). Furthermore, the anti‑cancer effects of ADA were examined in vivo on xenograft tumors derived from DLD1 human colorectal cancer cells subcutaneously inoculated in BALB/C nude mice. ADA (20 mg/kg orally) exhibited marked anti‑tumor activity, comparable to that of oxaliplatin (40 mg/kg), and dose‑dependently inhibited tumor growth (P<0.05), while combined administration of ADA and oxaliplatin produced the highest therapeutic effect. To the best of our knowledge, the present study was the first to indicate that ADA inhibits CDK2 and is a potential candidate drug for the treatment of human colorectal cancer.

Topical adapalene in the treatment of plantar warts; randomized comparative open trial in comparison with cryo-therapy

Background:

Various therapeutic modalities, which are available for treating plantar wart, have not been successful every time.

Aims:

To evaluate topical adapalene under occlusion in the treatment of plantar warts and compare it with cryo-therapy.

Materials and Methods:

50 patients with 424 plantar warts were included in this single center, two arm, prospective, randomized, control, open study. Patients were allocated randomly into two groups consisting of 25 patients each. Group A patients having 299 plantar warts were treated using adapalene gel 0.1% under occlusion while Group B patients having 125 warts were treated using cryo-therapy. All the patients were evaluated weekly till the clearance of all the warts and the results compared.

Result:

All the warts of 25 patients of Group A that were treated using adapalene gel 0.1% cleared in 36.71 ± 19.24 (55.95-17.47) days except those in one patient. In Group B, warts in all except one treated by cryo-therapy cleared in 52.17 ± 30.06 (82.23-22.11) days. There were no side effects like scar formation, irritation, erythema, or infections with adapalene group while in the cryo group scar was seen in 2 patients, pain in 24, erythema in 10, and infection in 3 patients.

Conclusion:

Adapalene gel 0.1% under occlusion is an effective, safe and easy to use treatment for plantar warts and may help clear lesions faster than cryo-therapy.

Evidence-based recommendations for the diagnosis and treatment of pediatric acne

INTRODUCTION

Acne vulgaris is one of the most common skin conditions in children and adolescents. The presentation, differential diagnosis, and association of acne with systemic pathology differs by age of presentation. Current acknowledged guidelines for the diagnosis and management of pediatric acne are lacking, and there are variations in management across the spectrum of primary and specialty care. The American Acne and Rosacea Society convened a panel of pediatric dermatologists, pediatricians, and dermatologists with expertise in acne to develop recommendations for the management of pediatric acne and evidence-based treatment algorithms.

METHODS

Ten major topic areas in the diagnosis and treatment of pediatric acne were identified. A thorough literature search was performed and articles identified, reviewed, and assessed for evidence grading. Each topic area was assigned to 2 expert reviewers who developed and presented summaries and recommendations for critique and editing. Furthermore, the Strength of Recommendation Taxonomy, including ratings for the strength of recommendation for a body of evidence, was used throughout for the consensus recommendations for the evaluation and management of pediatric acne. Practical evidence-based treatment algorithms also were developed.

RESULTS

Recommendations were put forth regarding the classification, diagnosis, evaluation, and management of pediatric acne, based on age and pubertal status. Treatment considerations include the use of over-the-counter products, topical benzoyl peroxide, topical retinoids, topical antibiotics, oral antibiotics, hormonal therapy, and isotretinoin. Simplified treatment algorithms and recommendations are presented in detail for adolescent, preadolescent, infantile, and neonatal acne. Other considerations, including psychosocial effects of acne, adherence to treatment regimens, and the role of diet and acne, also are discussed.

CONCLUSIONS

These expert recommendations by the American Acne and Rosacea Society as reviewed and endorsed by the American Academy of Pediatrics constitute the first detailed, evidence-based clinical guidelines for the management of pediatric acne including issues of special concern when treating pediatric patients.

Plantar warts treated with topical adapalene

Background:

Treatment of plantar warts caused by human papilloma virus (HPV) strain types 1, 2 and 4 is often difficult and a challenging problem. Various therapeutic modalities available for treating this problem have not been uniformly successful.

Purpose:

The purpose of present study is to evaluate the efficacy of adapalene applied locally with occlusion in plantar warts.

Materials and Methods:

A total of 10 patient with 118 plantar warts were included in an open study. All were treated by applying adapalene gel 0.1% after paring of warts if needed followed by occlusive dressing with polythene paper in each patient. The effects of the treatment were evaluated every week till the clearance of all warts.

Findings:

Adapalene was used in 10 patient having 118 plantar warts. All the warts cleared in 39±15.07 days. There was no side effects like scar formation, irritation, erythema or infection with adapalene.

Conclusion:

Adapalene clears the plantar warts faster compared to other modalities available.

Limitation:

Need trial with large number of patients.

A comparative trial of two retinoids commonly used in the treatment of acne vulgaris

BACKGROUND

Topical retinoids are highly effective treatments for acne vulgaris. The various formulations and concentrations available allow physicians to tailor therapies to individual patient's needs and minimize the cutaneous irritation that is often observed with the use of these drugs.

OBJECTIVE

To compare the efficacy and safety of tretinoin gel microsphere 0.1% with adapalene gel 0.1% in the treatment of acne vulgaris.

METHODS

A 12-week double-blind study was conducted, and patients were evaluated at baseline and at weeks 2, 3, 4, 6, 8, 10, and 12.

RESULTS

Although the two drugs displayed similar efficacy in the resolution of acne lesions at 12 weeks, a significantly greater reduction in the number of comedones was seen at week 4 among patients treated with tretinoin gel microsphere (p = 0.047). Patients receiving tretinoin gel microsphere had an increased incidence of dryness (weeks 8 and 10) and peeling (weeks 3, 6, 8, and 10) compared with those patients treated with adapalene gel, but the two groups were comparable with respect to erythema, burning/stinging, and itching.

CONCLUSION

Both drugs have similar efficacy in the resolution of acne lesions but tretinoin gel microsphere may result in a faster onset of action in the reduction of comedones compared to adapalene.

Update in retinoid therapy of acne

The pathogenesis of acne, the most common skin disease, is complex and multifactorial. Clinical experience has demonstrated that parallel targeting of various pathogenetic factors, achieved either by mono- or combination therapy with appropriate drugs, represents the most effective approach to treating acne. Topical retinoids have been shown to expulse mature comedones, reduce microcomedone formation, and exert immunomodulatory effects. They have broad anti-acne activity without the risk of inducing bacterial resistance, which justifies their use as first-line treatment in most types of noninflammatory and inflammatory acne and makes them uniquely suitable as long-term medication to maintain remission after cessation of initial combination therapy. Systemic isotretinoin as a monotherapeutic agent strongly affects all four major pathogenetic factors and has been, in the hand of experienced dermatologists, a potent and safe agent for the treatment of severe and recalcitrant acne forms for more that 20 years. However, patient counseling, careful monitoring, and evaluation and management of adverse events are necessary. The use of isotretinoin has experienced a drawback now that its indication has been lowered from a first-line to a second-line medication.

Expert committee recommendations for acne management

In 2003, an international committee of physicians and researchers in the field of acne, working together as the Global Alliance to Improve Outcomes in Acne, developed consensus guidelines for the treatment of acne. These guidelines were evidence based when possible but also included the extensive clinical experience of this group of international dermatologists. As a result of the evaluation of available data and the experience, significant changes occurred in the management routines for acne. The greatest change arose on the basis of improved understanding of acne pathophysiology. The recommendation now is that acne treatments should be combined to target as many pathogenic factors as possible. A topical retinoid should be the foundation of treatment for most patients with acne, because retinoids target the microcomedo, the precursor to all acne lesions. Retinoids also are comedolytic and have intrinsic antiinflammatory effects, thus targeting 2 pathogenic factors in acne. Combining a topical retinoid with an antimicrobial agent targets 3 pathogenic factors, and clinical trials have shown that combination therapy results in significantly faster and greater clearing as opposed to antimicrobial therapy alone. Oral antibiotics should be used only in moderate-to-severe acne, should not be used as monotherapy, and should be discontinued as soon as possible (usually within 8-12 weeks). Because of their effect on the microcomedo, topical retinoids also are recommended as an important facet of maintenance therapy.

Synthesis and biological evaluation of novel heterocyclic ionone-like derivatives as anti-inflammatory agents

Five- and six-membered heterocyclic ionone-like derivatives 4-6 have been synthesised in one step and with good yield from the key intermediate 3a and appropriate bifunctional reagents. Four were active as inhibitors of the respiratory burst of human neutrophils without affecting cell viability. The two most active compounds (5a,d) tested in neutrophil migration assays, were also found to be potent inhibitors of neutrophil chemotactic responsiveness. These two molecules could be considered as lead compounds of new drugs which can be an effective tool to treat psoriasis and related neutrophilic dermatoses.

Anti-inflammatory effects of tretinoin (all-trans-retinoic acid) 0.1% and adapalene 0.1% in rats

In this study, the anti-inflammatory effects of tretinoin (all-trans-retinoic acid) 0.1% cream and adapalene 0.1% gel were compared in rats to determine whether there was a difference between these agents. Thirty-six rats of either sex were divided into six groups (two control groups, and an etodolac, indomethacin, tretinoin and adapalene group) of six animals each. Each group was given different drugs or chemicals. The inhibitory activities of the drugs were determined on carrageenan-induced rat-paw oedema. The inhibition rate (53.48%) in the tretinoin group was found to be higher than adapalene and controls (P < 0.05). Adapalene was found to have an inhibition rate of 10.28%, and when compared with the other groups, was found to have no statistically significant anti-inflammatory activity. We conclude that tretinoin has a higher anti-inflammatory activity than adapalene and thus should be preferred for the treatment of inflammatory lesions.

Maintenance therapy for acne vulgaris: the fine balance between efficacy, cutaneous tolerability, and adherence

Maintenance therapy is defined as the regular use of appropriate therapeutic agents to ensure that acne remains in remission. Topical agents are the mainstay of maintenance therapy. A number of topical therapeutic options are available, including topical retinoids, benzoyl peroxide, and azelaic acid. The choice of topical agents should be based on a number of criteria: efficacy in addressing the subclinical microcomedo, which is the precursor lesion for both comedones and inflammatory lesions; tolerability, due to the need for application to a broader epidermal surface; and other properties that may enhance adherence. Patients may be more motivated to use agents that are easily integrated into their lifestyles and that have potential "skin-repairing" properties.

Current concepts of the pathogenesis of acne: implications for drug treatment

The pathogenesis of acne is complex, with strong evidence supporting the involvement of sebaceous hyperplasia, follicular hyperkeratinisation, bacterial hypercolonisation, as well as immune reactions and inflammation. High sebum concentrations and follicular hyperkeratinisation lead to a change of the follicular milieu with consecutive proliferation of bacteria, chiefly Propionibacterium acnes. This leads to further increased production of the pro-inflammatory cytokines interleukin-1alpha and tumour necrosis factor alpha by T cells and keratinocytes, leading to proliferation of both cell types. Follicular keratinocytes fail to differentiate by apoptosis and produce hypergranulosis similar to the impermeable skin outer layer, resulting in the formation of microcomedones. Further inflammatory responses lead to the development of increasing degrees of severity in inflammatory forms of acne. Retinoids aid the differentiation and reduce the hyperproliferation of keratinocytes, and can inhibit the migration of leucocytes. Combination therapy using retinoids plus benzoyl peroxide or antibacterials can treat existing acne lesions faster than the individual agents alone and can also prevent the development of new lesions. The new retinoids (e.g. adapalene) have not only the typical potent comedolytic activity but also anti-inflammatory effects. When added to antibacterial therapy, topical retinoids demonstrate faster and significantly greater reduction of inflammatory acne lesions and comedones than antibacterials alone.

The rationale for using a topical retinoid for inflammatory acne

Both comedogenesis and the development of inflammatory lesions in acne vulgaris appear to be related to genetic as well as immune processes. The key regulatory cytokine, interleukin-1alpha, has recently been documented as playing a major role in both the hypercornification and the orchestration of immune factors, ultimately resulting in noninflammatory and inflammatory lesions. Topical retinoids, such as tretinoin, and topical retinoid analogs, such as adapalene and tazarotene, help normalize the abnormal follicular keratinocyte desquamation - a key pathophysiologic factor in comedogenesis. This normalization also helps mitigate against the development of a propitious microenvironment for Propionibacterium acnes. Preclinical data suggest that topical retinoids and retinoid analogs may also have direct anti-inflammatory effects. A wealth of clinical data confirms that topical retinoids and retinoid analogs significantly reduce inflammatory lesions. Comparative clinical trials also demonstrate that adapalene has the best cutaneous tolerability profile of all these agents. Optimal therapy for inflammatory acne would involve the use of topical retinoids or retinoid analogs combined with oral or topical antibacterials.

The integral role of topical and oral retinoids in the early treatment of acne

This article will review the rationale for early use of topical retinoids alone or in combination with topical antimicrobials in light of the pathogenesis of microcomedones and later lesions. Knowledge of the pathogenic processes in acne vulgaris has risen dramatically over the last three decades. It is now widely accepted that acne is the result of four distinct processes: increased proliferation, cornification, and shedding of follicular epithelium; increased sebum production; colonization of the follicle with Propionibacterium acnes; and induction of inflammatory responses by bacterial antigens and cell signals. Clinical focus of disease management has shifted toward earlier treatment targeting these fundamental processes. Elimination of microcomedones, the precursor to all subsequent lesions, would optimize acne therapy by preventing the later inflammatory stages of disease. With the exception of oral isotretinoin, no single first-line agent addresses all pathogenic mechanisms. Topical retinoids have comedolytic and in some cases anti-inflammatory effects, but have no direct impact on P. acnes. Thus treatment with a combination of topical retinoid and topical antimicrobial is warranted. The former can also enhance penetration of the latter by increasing microcomedonal extrusion. In selecting a combination, one must consider efficacy, cost, and likelihood of compliance. Once thought to be effective primarily for treating comedones, topical retinoids have also been demonstrated to be effective in reducing inflammatory lesions. The activity of a topical retinoid combined with an antimicrobial agent has been shown to clear more lesions and to clear them more rapidly than antimicrobial therapy alone. Topical retinoids are also used effectively to maintain remissions.

Potential anti-inflammatory effects of topical retinoids and retinoid analogues

The topical retinoid tretinoin and topical retinoid analogues such as adapalene and tazarotene help normalize hyperkeratinization in acne vulgaris and have demonstrated significant anti-inflammatory effects in experimental trials. Inhibition of various immune factors, including the activity of leukocytes, the release of proinflammatory cytokines and other mediators, and the expression of transcription factors and toll receptors involved in immunomodulation, has emerged in both in vitro studies and in vivo animal experiments. These multiple mechanisms of action should encourage clinicians to consider these agents in the first-line management of inflammatory acne lesions.

Pharmacology of adapalene

Adapalene, a synthetic retinoid, is a new drug proposed for the treatment of acne patients. Studies on the in vitro and in vivo pharmacology of adapalene have shown that it is very active on cell and tissue proliferation and differentiation. Furthermore, adapalene has anti-inflammatory potential as determined by its anti-AP1 activity. Adapalene interacts selectively with the nuclear receptors RAR beta and RAR gamma, and its activity on proliferation and differentiation can be blocked by a RAR beta-gamma antagonist. Because RAR beta is not expressed in human keratinocytes, the effect of adapalene on the major cell type of the epidermis is certainly mediated by its interaction with RAR gamma. The unique pharmacological properties of adapalene may explain why, when compared to tretinoin, it has an improved therapeutic ratio due to its better tolerance.

A comparison of the efficacy and safety of adapalene gel 0.1% and tretinoin gel 0.025% in the treatment of acne vulgaris: a multicenter trial

BACKGROUND

Adapalene is a new synthetic retinoid analogue developed for the topical treatment of acne vulgaris.

OBJECTIVE

The study was designed to compare the efficacy and safety and adapalene gel 0.1% with tretinoin gel 0.025% in the treatment of grade II to II facial acne vulgaris.

METHODS

Three hundred twenty-three patients were enrolled in this investigator-masked, randomized, parallel group, multicenter trial. Patients applied the test materials to the entire facial area daily, for a period of 12 weeks. Efficacy and cutaneous tolerance were assessed at baseline and weeks 2,4,8, and 12. Efficacy was determined by investigator counts of noninflammatory open and closed comedones, and inflammatory papules and pustules, as well as global improvement. Cutaneous tolerance was evaluated by erythema, scaling, and dryness, along with burning and pruritus.

RESULTS

Staring at weeks 2 and 4, adapalene gel produced numerically greater lesion reductions than did tretinoin gel for all lesion types. At week 12, the mean percent reduction in the different lesion counts was as follow: 49% versus 37% for total lesions (p<0.01); 46% versus 33% for noninflammatory lesions (p=0.02); 48% versus 38% for inflammatory lesions (p=0.06) in adapalene and tretinoin gel treatment groups, respectively. Cutaneous side effects were limited to a mild "retinoid dermatitis" occurring in both treatment groups; however, patients treated with adapalene gel tolerated this therapy significantly better than those treated with tretinoin gel. Laboratory test evaluations (hematology, blood chemistries, urinalysis) were performed in 54 patients before and after 3 months of treatment. No clinically significant changes were observed.

CONCLUSION

Adapalene gel 0.1% applied once daily was significantly more effective in reducing acne lesions and was better tolerated than tretinoin gel 0.025% in the treatment of acne vulgaris.