Efficacy and Safety of Azelaic Acid Nanocrystal-Loaded In Situ Hydrogel in the Treatment of Acne Vulgaris

Strategies to Enhance Nanocrystal Formulations for Overcoming Physiological Barriers Across Diverse Routes of Administration

Poor aqueous solubility and bioavailability limit the translation of new drug candidates into clinical applications. Nanocrystal formulations offer a promising approach for improving the dissolution rate and saturation solubility. These formulations are applicable for various routes of administration, with each presenting unique opportunities and challenges posed by the physiological barriers. The development of nanocrystal formulation requires comprehensive understanding of these barriers and the biological environment, along with strategic modulation of particle size, surface properties, and charge to facilitate improved bioavailability to the target site. This review focuses on applications of nanocrystals for diverse administration routes and strategies in overcoming anatomical and physiological delivery barriers. The orally administered nanocrystals benefit from increased solubility, prolonged gastrointestinal retention, and enhanced permeation. However, the nanocrystals, due to their small size and high surface area, are susceptible to aggregation in the presence of gastric fluids and are more prone to enzymatic degradation compared to the macrocrystalline form. Although nanocrystal formulations are composed of pure API, the application of excipients like stabilizers reduces the aggregation and improves formulation stability, solubility, and bioavailability. Some excipients can facilitate sustained drug release. Emerging research in nanocrystals include their application in blood-brain barrier transport, intranasal delivery, stimuli responsiveness, multifunctionality, and diagnostic purposes. However, the challenges related to toxicity, scale-up, and clinical translation still need further attention. Overall, nanocrystal engineering serves as a versatile platform for expanding the therapeutic potential of insoluble drugs and enabling dose reduction for existing drugs, which can minimize toxicity and improve bioavailability at lower dosages.

Nanocrystals and nanosuspensions: an exploration from classic formulations to advanced drug delivery systems

Nanocrystals and nanosuspensions have become realistic approaches to overcome the formulation challenges of poorly water-soluble drugs. They also represent a less-known but versatile platform for multiple therapeutic applications. They can be integrated into a broad spectrum of drug delivery systems including tablets, hydrogels, microneedles, microparticles, or even functionalized liposomes. The recent progresses, challenges, and opportunities in this field are gathered originally together with an informative case study concerning an itraconazole nanosuspension-in-hydrogel formulation. The translational aspects, historical and current clinical perspectives are also critically reviewed here to shed light on the incoming generation of nanocrystal formulations.

Advances in polymeric nano-delivery systems targeting hair follicles for the treatment of acne

Acne is a common chronic inflammatory disorder of the sebaceous gland in the hair follicle. Commonly used external medications cause skin irritation, and the transdermal capacity is weak, making it difficult to penetrate the cuticle skin barrier. Hair follicles can aid in the breakdown of this barrier. As nanomaterials progress, polymer-based nanocarriers are routinely used for hair follicle drug delivery to treat acne and other skin issues. Based on the physiological and anatomical characteristics of hair follicles, this paper discusses factors affecting hair follicle delivery by polymer nanocarriers, summarizes the common combination technology to improve the targeting of hair follicles by carriers, and finally reviews the most recent research progress of different polymer nanodrug-delivery systems for the treatment of acne by targeting hair follicles.

Azelaic Acid: Mechanisms of Action and Clinical Applications

AZA is a non-phenolic, saturated dicarboxylic acid with nine carbon atoms, naturally produced by the yeast Malassezia. It has diverse physiological activities, including antibacterial, anti-keratinizing, antimelanogenic, antioxidant and anti-inflammatory effects. AZA is widely used in dermatology and is FDA-approved for treating papulopustular rosacea. It also shows significant efficacy in acne vulgaris and melasma. This review summarizes the mechanisms of action and clinical applications of AZA, aiming to provide theoretical support for its clinical and cosmetic use and to facilitate further research.

Functional Nanostructured Lipid Carrier-Enriched Hydrogels Tailored to Repair Damaged Epidermal Barrier

In this study, a functional nanostructured lipid carriers (NLCs)-based hydrogel was developed to repair the damaged epidermal skin barrier. NLCs were prepared via a high-energy approach, using argan oil and beeswax as liquid and solid lipids, respectively, and were loaded with ceramides and cholesterol at a physiologically relevant ratio, acting as structural and functional compounds. Employing a series of surfactants and optimizing the preparation conditions, NLCs of 215.5 ± 0.9 nm in size and a negative zeta potential of -42.7 ± 0.9 were obtained, showing acceptable physical and microbial stability. Solid state characterization by differential scanning calorimetry and X-ray powder diffraction revealed the formation of imperfect crystal NLC-type. The optimized NLC dispersion was loaded into the gel based on sodium hyaluronate and xanthan gum. The gels obtained presented a shear thinning and thixotropic behavior, which is suitable for dermal application. Incorporating NLCs enhanced the rheological, viscoelastic, and textural properties of the gel formed while retaining the suitable spreadability required for comfortable application and patient compliance. The NLC-loaded gel presented a noticeable occlusion effect in vitro. It provided 2.8-fold higher skin hydration levels on the ex vivo porcine ear model than the NLC-free gel, showing a potential to repair the damaged epidermal barrier and nourish the skin actively.

Progress in Topical and Transdermal Drug Delivery Research-Focus on Nanoformulations

Skin is the largest organ and a multifunctional interface between the body and its environment. It acts as a barrier against cold, heat, injuries, infections, chemicals, radiations or other exogeneous factors, and it is also known as the mirror of the soul. The skin is involved in body temperature regulation by the storage of fat and water. It is an interesting tissue in regard to the local and transdermal application of active ingredients for prevention or treatment of pathological conditions. Topical and transdermal delivery is an emerging route of drug and cosmetic administration. It is beneficial for avoiding side effects and rapid metabolism. Many pharmaceutical, technological and cosmetic innovations have been described and patented recently in the field. In this review, the main features of skin morphology and physiology are presented and are being followed by the description of classical and novel nanoparticulate dermal and transdermal drug formulations. The biophysical aspects of the penetration of drugs and cosmetics into or across the dermal barrier and their investigation in diffusion chambers, skin-on-a-chip devices, high-throughput measuring systems or with advanced analytical techniques are also shown. The current knowledge about mathematical modeling of skin penetration and the future perspectives are briefly discussed in the end, all also involving nanoparticulated systems.

Hair Follicle-Targeted Delivery of Azelaic Acid Micro/Nanocrystals Promote the Treatment of Acne Vulgaris

Purpose

Acne vulgaris is a chronic inflammatory skin disorder centered on hair follicles, making hair follicle-targeted delivery of anti-acne drugs a promising option for acne treatment. However, current researches have only focused on the delivering to healthy hair follicles, which are intrinsically different from pathologically clogged hair follicles in acne vulgaris.

Patients and Methods

Azelaic acid (AZA) micro/nanocrystals with different particle sizes were prepared by wet media milling or high-pressure homogenization. An experiment on AZA micro/nanocrystals delivering to healthy hair follicles was carried out, with and without the use of physical enhancement techniques. More importantly, it innovatively designed an experiment, which could reveal the ability of AZA micro/nanocrystals to penetrate the constructed clogged hair follicles. The anti-inflammatory and antibacterial effects of AZA micro/nanocrystals were evaluated in vitro using a RAW264.7 cell model stimulated by lipopolysaccharide and a Cutibacterium acnes model. Finally, both the anti-acne effects and skin safety of AZA micro/nanocrystals and commercial products were compared in vivo.

Results

In comparison to commercial products, 200 nm and 500 nm AZA micro/nanocrystals exhibited an increased capacity to target hair follicles. In the combination group of AZA micro/nanocrystals and ultrasound, the ability to penetrate hair follicles was further remarkably enhanced (ER value up to 9.6). However, toward the clogged hair follicles, AZA micro/nanocrystals cannot easily penetrate into by themselves. Only with the help of 1% salicylic acid, AZA micro/nanocrystals had a great potential to penetrate clogged hair follicle. It was also shown that AZA micro/nanocrystals had anti-inflammatory and antibacterial effects by inhibiting pro-inflammatory factors and Cutibacterium acnes. Compared with commercial products, the combination of AZA micro/nanocrystals and ultrasound exhibited an obvious advantage in both skin safety and in vivo anti-acne therapeutic efficacy.

Conclusion

Hair follicle-targeted delivery of AZA micro/nanocrystals provided a satisfactory alternative in promoting the treatment of acne vulgaris.

Exploring Acne Treatments: From Pathophysiological Mechanisms to Emerging Therapies

Acne vulgaris is a common dermatological condition that can present across different ages but predominantly affects adolescents and young adults. Characterized by various lesion types, the pathogenesis of acne is complex, involving genetic, hormonal, microbial, and inflammatory factors. This review comprehensively addresses current and emerging acne management strategies, emphasizing both topical and systemic treatments, procedural therapies, and dietary modifications. Key topical agents include retinoids, benzoyl peroxide, antibiotics, and other specialized compounds. Systemic options like antibiotics, hormonal therapies, and retinoids offer significant therapeutic benefits, particularly for moderate to severe cases. Procedural treatments such as laser devices, photodynamic therapy, chemical peels, and intralesional injections present viable alternatives for reducing acne symptoms and scarring. Emerging therapies focus on novel biologics, bacteriophages, probiotics, and peptides, providing promising future options. This review underscores the importance of personalized approaches to treatment due to the multifaceted nature of acne, highlighting the potential of innovative therapies for improving patient outcomes.

In vitro Evaluation of Skin Related Enzyme Inhibitory Effect and Emulgel Formulation Development Studies of Onobrychis Argyrea subsp. Argyrea with Phytochemical Analysis

Species of Onobrychis have been used to treat skin disorders such as wounds and cuts in folk medicine and Onobrychis argyrea subsp. argyrea (OA) commonly known as 'silvery sainfoin', is a member of this genus. In this study, it was aimed to investigate the skin-related biological activities and phytochemical characterization of OA. Moreover, an emulgel formulation was developed from the main methanolic extract of the plant (OAM). Initially, to identifiy of the active fractions, aerial parts of the plant material was extracted with methanol and fractionated by n-hexane, chloroform, ethyl acetate and n-butanol, respectively. Antioxidant activity was determined by CUPRAC, TOAC, FRAP and DPPH assays. Thereafter, the inhibition potential of OAM, novel formulation and all fractions was measured against elastase, collagenase, tyrosinase and hyaluronidase enzymes. OAM was analyzed and characterized by LC/MS-MS. The major bioactive flavonoids which are rutin and isoquercetin were measured and compared as qualitative and quantitative via high performance thin layer chromatography (HPTLC) analysis in OAM and fractions. The results showed that extracts of OA can be a potential cosmeceutical agent for skin related problems.

New Insights into Pharmaceutical Nanocrystals for the Improved Topical Delivery of Therapeutics in Various Skin Disorders

Nanotechnology has provided nanostructure-based delivery of drugs, among which nanocrystals have been investigated and explored for feasible topical drug delivery. Nanocrystals are nano-sized colloidal carriers, considered pure solid particles with a maximum drug load and a very small amount of stabilizer. The size or mean diameter of the nanocrystals is less than 1 μm and has a crystalline character. Prominent synthesis methods include the utilization of microfluidic- driven platforms as well as the milling approach, which is both adaptable and adjustable. Nanocrystals have shown a high capacity for loading drugs, utilization of negligible amounts of excipients, greater chemical stability, lower toxic effects, and ease of scale-up, as well as manufacturing. They have gained interest as drug delivery platforms, and the significantly large surface area of the skin makes it a potential approach for topical therapeutic formulations for different skin disorders including fungal and bacterial infections, psoriasis, wound healing, and skin cancers, etc. This article explores the preparation techniques, applications, and recent patents of nanocrystals for treating various skin conditions.

Acne vulgaris: A review of the pathophysiology, treatment, and recent nanotechnology based advances

BACKGROUND

Globally, Acne Vulgaris is a widespread, chronic inflammatory condition of the pilosebaceous follicles. Acne is not fatal, but depending on its severity, it can leave the sufferer with scars, irritation, and significant psychological effects (including depression). In the current review, we have included various factors for acne and their treatment explained. It also narrated the current medicament and the new investigation dosage forms with clinical phases information provided.

MAIN BODY OF THE ABSTRACT

Acne's pathophysiology involves four important factors: excessive sebum production, hyperkeratinization of pilosebaceous follicles, hyperproliferation of propionibacterium acnes (P. acnes), and inflammation. Identifying both inflammatory (Papule, pustule, nodule, and cyst) and non-inflammatory (black heads, white heads) acne lesions is necessary for diagnosing and treating acne vulgaris.

SHORT CONCLUSION

In this review, traditional therapy approaches such as topical (i.e., retinoids and antibiotics), systemic (i.e., retinoids, antibiotics, and hormonal), and physical therapies are briefly discussed. In addition, we highlight the issues posed by P. acne's resistance to the antibiotics used in commercially available medications and the necessity for novel therapeutic techniques. Finally, we examined a few innovative acne therapies pending clinical trial approval and commercial acne medications.

Nanocrystals in cosmetics and cosmeceuticals by topical delivery

The main issues with local delivery of cosmetics are their high sensitivity and limited drug loading of active pharmaceutical ingredient. Nanocrystal technology offers consumers cutting-edge and effective products and exhibits enormous development potential in the beauty business as a new delivery method to address the issue of low solubility and low permeability of sensitive chemicals. In this review, we described the processes for making NCs, along with the impacts of loading and the uses of different carriers. Among them, nanocrystalline loaded gel and emulsion are widely used and may further improve the stability of the system. Then, we introduced the beauty efficacy of drug NCs from five aspects: anti-inflammation and acne, anti-bacterial, lightening and freckle removal, anti-aging as well as UV protection. Following that, we presented the current scenario about stability and safety. Finally, the challenges and vacancy were discussed along with the potential uses of NCs in the cosmetics industry. This review serves as a resource for the advancement of nanocrystal technology in the cosmetics sector.

Development of a Self-Assembled Hydrogels Based on Carboxymethyl Chitosan and Oxidized Hyaluronic Acid Containing Tanshinone Extract Nanocrystals for Enhanced Dissolution and Acne Treatment

This study aimed to construct a pH-responsive nanocrystalline hydrogel drug delivery system for topical delivery of insoluble drugs based on the self-assembly behavior of carboxymethyl chitosan (CMC) and oxidized hyaluronic acid (OHA). The tanshinone nanocrystal (TNCs) extract was prepared by dielectric milling method, the type and ratio of stabilizer of the drug were investigated to optimize the prescription, and the effector surface method was used to optimize the preparation process. OHA was prepared by the sodium periodate oxidation method, and the concentration of CMC and OHA was optimized using gel formation time as an indicator. OHA was dissolved in TNCs and self-assembled with CMC solution to form tanshinone extract nanocrystal hydrogels (CMC-OHA/TNCs), of which the physicochemical properties and in vitro antibacterial activity were evaluated. Results showed that the optimized prescription and process could produce tanshinone extract nanocrystals with a particle size of (223.67 ± 4.03) nm and a polydispersity index (PDI) of 0.2173 ± 0.0008. According to SEM and XRD results, TNCs were completely wrapped in the hydrogel as nanoparticles, and the crystallinity of TNCs was reduced and the diffraction peaks in CMC-OHA/TNCs almost disappeared. In vitro, transdermal test results showed that CMC-OHA/TNCs could release the drug continuously at the acne lesions. The cell-counting kit-8 (CCK-8) assay confirmed that the CMC-OHA/TNCs had no obvious cytotoxicity. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CMC-OHA/TNCs against Propionibacterium acnes and Staphylococcus aureus were significantly lower and the diameter of the inhibition circle was obviously higher than that of TNCs and tanshinone extract crude suspension. This study demonstrated that CMC-OHA/TNCs was a promising delivery system for topical delivery of insoluble drugs, which could improve the solubility of tanshinone extract and enhance its in vitro bacterial inhibitory activity.

Use of Patient-Reported Outcomes in Acne Vulgaris and Rosacea Clinical Trials From 2011 to 2021: A Systematic Review

Importance

Acne and rosacea have substantial implications for quality of life, and it is therefore important to ensure the patient's voice is being captured in pivotal randomized clinical trials (RCTs). Although patient-reported outcome measures (PROMs) are a valuable tool to capture the patient perspective, little is known about use of PROMs in RCTs on acne and rosacea.

Objective

To characterize the use of PROMs in RCTs on acne and rosacea.

Evidence Review

A systematic literature search was conducted using the search terms acne vulgaris and rosacea in the following databases: MEDLINE through PubMed, Embase, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews. A modified search hedge for RCTs from the McGill Library was applied. All phase 2, 3, and 4 RCTs published between December 31, 2011, through December 31, 2021, that evaluated the efficacy and safety of therapies for acne and rosacea vs any comparator were eligible for inclusion.

Findings

A total of 2461 publications describing RCTs were identified, of which 206 RCTs met the inclusion criteria (163 trials [79%] on acne and 43 [21%] on rosacea). At least 1 PROM was used in 53% of trials (110) included; PROM use was more common in rosacea RCTs (67% [n = 29]) compared with acne RCTs (50% [n = 81]). At least 1 dermatology-specific (13% [n = 27]) or disease-specific (14% [n = 28]) PROM was included in the RCTs analyzed. Only 7% of trials (14) included a PROM as a primary outcome measure. There was no statistically significant increase in PROM inclusion over the study period (11 of 21 trials in 2011 vs 5 of 12 trials in 2021).

Conclusions and Relevance

In this systematic review, PROMs were included in approximately one-half of acne and rosacea RCTs performed over the study period. In addition, PROMs were rarely used as a primary outcome measure, and inclusion of PROMs has not increased substantially over the past 10 years. Increasing use of PROMs in RCTs can ensure that the patient's perspective is captured during the development of new treatments for acne and rosacea.

Azelaic acid loaded chitosan and HPMC based hydrogels for treatment of acne: formulation, characterization, in vitro-ex vivo evaluation

In this study, hydrogels containing azelaic acid were developed using chitosan or HPMC (1-7%) for local treatment of acne vulgaris. Physicochemical properties such as viscosity, pH and mechanical properties were evaluated. In vitro release and ex vivo permeability studies were performed using Franz diffusion cell system. The pH of the hydrogels were highly compatible with the skin pH and varied between 4.38-5.84. The cumulative release percentages of the hydrogels at the end of 6 hours were 65-78%, whereas the marketed product yielded 50% drug release. According to the ex vivo permeability results, azelaic acid accumulated in the skin were found to be 9.38 ± 0.65% (marketed cream), 19.53 ± 1.06% (K3), 10.96 ± 1.91% (H6). The antiacne studies with Cutibacterium acnes revealed that K3 (29.45 ± 0.95) and H6 (32.35 ± 0.15) had higher inhibition zones compared to the marketed cream (24.50 ± 0.90). Additionally, the gels were found to be highly stable as a result of the stability studies for 6 months. Among the hydrogels that were prepared based on experimental findings, K3 (3% Chitosan) and H6 (6% HPMC) represented elevated in vitro release profile, higher permeability and increased antiacne activity. The findings of this research suggest that the developed hydrogels might be an alternative to the marketed product.

Dermatology: how to manage acne vulgaris

Background

Acne vulgaris is the most common skin disease that can lead to disfigurement and psychological distress. This article aims to provide a narrative updated review on the management of acne vulgaris.

Methods

A PubMed search was performed with Clinical Queries using the key term “acne”. The search strategy included clinical trials, meta-analyses, randomized controlled trials, observational studies and reviews. The search was restricted to articles published in English.

Results

Treatments of acne include proper skin care, topical medications, oral medications and procedural therapies. Topical agents are the first-line treatment for mild-to-moderate acne and can be used as combination therapy for more severe acne. Systemic therapies are usually prescribed for the initial treatment of moderate-to-severe acne as well as for acne that is refractory to topical therapies.

Conclusion

Topical retinoids are the drugs of choice for the treatment and maintenance therapy of patients with mild-to-moderate acne vulgaris. Depending on the severity of the acne, topical retinoids may be used alone or in combination with benzoyl peroxide and topical or oral antibiotics. Oral antibiotics are an important therapy for inflammatory acne unresponsive to topical therapy. Neither topical nor oral antibiotics should be used as monotherapy. Oral contraceptives and/or spironolactone are useful for many women with acne. Oral isotretinoin is the drug of choice for severe, extensive, nodular acne vulgaris but is also often used in moderate cases where scarring is evident, acne-related psychosocial distress is significant or other treatment modalities have failed.