Intradermal and follicular delivery of adapalene liposomes

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.

Physicochemical characterization and environmental stability of a curcumin-loaded Pickering nanoemulsion using a pea protein isolate-dextran conjugate via the Maillard reaction

This study investigated pea protein isolate (PPI) and dextran (DX) conjugates produced via the Maillard reaction as Pickering stabilizers for various food applications. The results found that as heating time increased (0-5 h), the grafting degree heightened. The PPI-DX conjugate exhibited a rough porous surface in contrast to native PPI, accompanied by changes in molecular weight and secondary structure. Additionally, the aggregation of low-solubility PPI was partially inhibited due to the contribution of increased solubility and reduced surface hydrophobicity by glycation. Curcumin-loaded Pickering nanoemulsions stabilized with PPI-DX had smaller droplets and higher curcumin encapsulation (greater than80 %) than PPI-stabilized nanoemulsions. PPI-DX adsorbed on the interface showed improved physical stability compared to PPI alone, even after various pH conditions and three heat treatments. The nanoemulsion stabilized with PPI-DX demonstrated improved apparent viscosity and dispersion stability. These findings highlight the effectiveness of PPI-DX conjugates as stabilizers for developing stable and functional Pickering nanoemulsions.

Evaluation of the in vitro performance of generic and original adapalene gel

OBJECTIVE

The aim was to evaluate the difference of the in vitro behavior between the commercially available generic adapalene gel and original product with Topical Classification System (TCS), and to analyze the effect of changes of excipients on the release behavior.

SIGNIFICANCE

Establishing in vitro performance assays to understand the impact of formulation variables on the critical quality attributes (CQA) is critical for the quality assessment of semi-solid generic drug.

METHODS

In vitro release (IVR), in vitro permeation (IVP), viscosity, and pH measurement methods for adapalene gels were established and validated. The differences between generic adapalene gel from 7 companies and original products were evaluated by correlation analysis (CA) and principal component analysis (PCA), and the relationship among 4 parameters was elucidated. The effect of excipients on the above variables was examined by univariate tests.

RESULTS

There were some differences between the gels of 5 of the 7 imitation enterprises and reference listed drug (RLD). There were varying degrees of correlation between viscosity, pH, the adapalene amount retained in skin and release rate. The result validated the key role of IVR, and identified that pH value, type of suspending agent, the amount of carbomer, etc. had certain effects on the release rate.

CONCLUSIONS

The factors mentioned above should be considered when developing and manufacturing generic adapalene gels, and the application of TCS in the evaluation of generic topical drugs was advanced. Additionally, our research revealed some discrepancies from USP<1724>, which could be valuable information for the revision.

Development of Adapalene Loaded Liposome Based Gel for Acne

Retinoids are considered the mainstay treatment for moderate to severe acne. Adapalene, a third-generation retinoid, has physiochemical properties which hinder the effective delivery of the drug to the skin. Therefore, the current study aimed to develop and evaluate adapalene liposomal loaded gel (ADA-LP gel) for the effective management of acne to improve tolerability and delivery to targeted sites as compared to the conventional dosage form of the drug. A novel spontaneous phase transition method (SPT) was used to formulate liposomes. Liposomal formulation (ADA-LP) was prepared and optimized based on particle size, zeta potential, and PDI. Optimized formulation was further characterized by different techniques and loaded into Carbopol gel. In vitro drug release, ex vivo permeation, and in vivo studies were performed using the prepared adapalene-loaded liposomal-based gel. The in vivo study was done employing the testosterone-induced acne model in mice. The optimized formulation had a size of 181 nm, PDI 0.145, and a zeta potential of -35 mV, indicating that the formulation was stable. Encapsulation efficiency was 89.69 ± 0.5%. ADA-LPs were loaded into the gel. Prepared ADA-LP showed a 79 ± 0.02% release of drug in a sustained manner, within 24 h. The ex vivo permeability study showed a total of 43 ± 0.06 µg/cm² of drug able to permeate through the skin within 24 h. Moreover, only 28.27 ± 0.04% was retained on the epidermis. The developed ADA-LP gel showed significant improvement in the acne lesions in mice with no visible scars and inflammation on the skin. Therefore, ADA-LP-based gel could be a promising carrier system for the safe and effective delivery of Adapalene.

Biodistribution of the photosensitizer temoporfin after in vivo topical application of temoporfin-loaded invasomes in mice bearing subcutaneously implanted HT29 tumor

Temoporfin (mTHPC) has a great potential for the topical photodynamic therapy. However, it presents a highly hydrophobic second generation photosensitizer with low percutaneous penetration. In order to use mTHPC for dermal/transdermal delivery it is necessary to employ some of the penetration enhancement methods. In this study invasomes were used as a highly effective drug nanocarrier system to enhance its skin penetration, being composed of non-hydrogenated soybean lecithin (10% w/v), ethanol (3.3%w/v), a mixture of terpenes (1% w/v of the mixture cineole:citral:d-limonene = 45:45:10 v/v) and phosphate buffer saline up to 100% w/v. A pharmacokinetic/biodistribution study was performed in mice bearing s.c. implanted human colorectal tumor HT29 upon the application of mTHPC-loaded invasomes onto the skin above the underlying tumor. The aim was to obtain the biodistribution profile of mTHPC i.e. to gain data on mTHPC-distribution in the body (tumor, treated skin, muscle, blood, liver and untreated skin) of mice after the topical application of mTHPC-loaded invasomes. The results revealed that a significant mTHPC-amount was found in treated skin already after 2 h of incubation time. As to the tumor, significant amounts were found after 12 h, while the highest mTHPC-amount was found after 24 h. This study showed that invasomes applied onto the skin may deliver mTHPC to the tumor being necessary for PDT. Since mTHPC was also found in blood and liver, transdermal mTHPC delivery was confirmed. In conclusion, mTHPC-invasomes could be used for topical PDT of cutaneous and subcutaneous lesions, however with general photoxicity induced by systemic apsorption of mTHPC lasting only for 2 weeks. Additionally, due to systemic absorption of mTHPC after invasomes application onto the skin, they could be used transdermally for the PDT treatment of diseases, which need systemic drug absorption. However, it should be emphasized that mice were used in the study, differing in the skin properties compared to human skin. Thus, additional studies should be conducted.

Research-based findings on scope of liposome-based cosmeceuticals: an updated review

Background

Cosmeceuticals are cosmetic products with biologically active components that have drug-like benefits. Cosmeceuticals are currently rapidly growing segments encompassing the personal care industry and numerous topical cosmetics-based therapies for treating different skin conditions. The barrier nature of skin causes limitations to topical treatment. The effectiveness of this cosmeceutical product has been enhanced a few folds by using nanotechnological modifications.

Main body

PubMed electronic searches for the literature were performed using combinations of the following terms: “cosmeceutical,” “liposome-based cosmeceuticals,” “acne and liposome,” “photo-aging and liposome,” “hyperpigmentation and liposome,” “wrinkles and liposome,” “fungal infections and liposome,” and “hair damage and liposome” from the earliest publication date available to January 5, 2022. Among the various nanotechnological approaches, liposomes offer numerous advantages such as topical cosmeceutical products, starting from improved moisturization, biodegradability, biocompatibility, enhanced permeation and retention, improved bioavailability of the active ingredients, increased esthetic appeal of cosmeceutical products, slow and extended dermal release. This review outlines various liposome-based cosmeceutical products that has been investigated to treat skin disorders such as photoaging, wrinkles, hyperpigmentation, hair damage and fungal infections.

Conclusion

Liposome-based cosmeceuticals provide a better opportunity to deliver therapeutic moiety for various skin conditions and offer potential promise for future clinical applications.

Graphical Abstract

Comparing the delivery to the hair bulb of two fluorescent molecules of distinct hydrophilicities by different nanoparticles and a serum formulation

The follicular route is an important drug penetration pathway in any topical application, either concerning dermatological and cosmetic skin treatments or any transdermal administration regimen. Efficient transport into follicles will depend on drug inherent properties but also on the chosen vehicle. The main study goal was to compare several systems for the delivery to the hair bulb of two fluorescent molecules of different water affinities: the hydrophobic Nile Red and the quite similar but hydrophilic Nile Blue. Three common nanoparticle types were compared in terms of encapsulation efficiency and stability: liposomes, ethosomes and polymeric nanoparticles. A liquid serum-like formulation was also developed, adjusting the final ethanol amount to the type of dye to be solubilized. Then, this formulation and the nanoparticle systems that successfully passed characterization and stability stages were further studied on their ability to reach the bulb. The serum formulation was able to deliver, both drug models, to deeper follicular regions than nanoparticles. Attending to the envisioned zone target of the follicle, the simplest approach proved to be the best choice from all the systems tested in this work. Nonetheless, nanocarriers and the inherent complexity of their manufacturing processes may be justified under very specific requirements.

Dermal delivery and follicular targeting of adapalene using PAMAM dendrimers

Acne is a chronic dermatological disease of pilosebaceous units existing in the form of hair follicles (HFs) and accompanying sebaceous glands. In topical acne treatment, localisation of drug substance at the target site, in pilosebaceous units, especially in HFs is essential. The aims of this study were to develop and optimise adapalene (ADA)-loaded PAMAM dendrimer-based nanocarriers for topical acne treatment and to prepare gel formulations of the selected nanocarriers and to characterise their rheological properties and spreadability. ADA accumulation in HFs and in the skin from PAMAM dendrimers' aqueous colloidal formulations and their gel formulations were quantitatively determined using punch biopsy technique. Follicular targeting efficiency from PAMAM dendrimers and their gel formulation was compared with the commercial gel product, Differin^® Gel. The localisation of fluorescently labelled PAMAM dendrimers was visualised using a confocal microscope, which confirmed a successful delivery of the carrier system to the HFs. It was also quantified that PAMAM dendrimers improved follicular localisation and skin deposition of ADA. PAMAM dendrimers' gel formulation including lower ADA doses compared with the commercial product exhibited efficient performance in terms of drug accumulation in HFs. In vitro cell viability studies showed the relative safety of G2-PAMAM dendrimers which could be considered to possibly be well tolerated by the skin. Overall, PAMAM dendrimers' potential to selectively target drugs to the site of action, reduce dose administrated, therefore minimise side effects and provide efficiency in topical treatment of dermatological diseases such as acne was shown.

Foray into Concepts of Design and Evaluation of Microemulsions as a Modern Approach for Topical Applications in Acne Pathology

With a fascinating complexity, governed by multiple physiological processes, the skin is considered a mantle with protective functions which during lifetime are frequently impaired, triggering dermatologic disorders. As one of the most prevalent dermatologic conditions worldwide, characterized by a complex pathogenesis and a high recurrence, acne can affect the patient's quality of life. Smart topical vehicles represent a good option in the treatment of a versatile skin condition. By surpassing the stratum corneum known for diffusional resistance, a superior topical bioavailability can be obtained at the affected place. In this direction, the literature study presents microemulsions as a part of a condensed group of modern formulations. Microemulsions are appreciated for their superior profile in matters of drug delivery, especially for challenging substances with hydrophilic or lipophilic structures. Formulated as transparent and thermodynamically stable systems, using simplified methods of preparation, microemulsions have a simple and clear appearance. Their unique structures can be explained as a function of the formulation parameters which were found to be the mainstay of a targeted therapy.

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.

Formulation and evaluation of a topical liposomal gel containing a combination of zedoary turmeric oil and tretinoin for psoriasis activity

This study was to develop a combination of zedoary turmeric oil (ZTO) and tretinoin (TRE)-loaded liposomal gel as a topical drug delivery system. We used a combination of single-factor experiment and orthogonal experiment to systematically optimize encapsulation process of the compound liposomes. The optimized liposome vesicles were incorporated into Carbopol gel matrix and studied by continuous in vitro (skin penetration and retention) and in vivo (anti-psoriatic activity using mouse vaginal model and mouse tail model) experiments. The optimized liposomes had an entrapment efficiency (EE) of ZTO was (64.63 ± 1.00)%, EE of TRE was (90.33 ± 0.72)%, drug loading (DL) of ZTO was (9.09 ± 0.14)%, DL of TRE was (1.43 ± 0.02)%, particle size of 257.41 ± 7.58 nm, polydispersity index (PDI) of 0.10 ± 0.04 and zeta potential of -38.77 ± 0.81 mV. Transmission electron microscopy showed liposomes had a regular spherical surface. After 1-month storage at (4 ± 2)°C, the optimized liposome preparations maintained its stability. In vitro study indicated that liposome formulations could significantly prolong the penetration of drugs into the hair follicles of mice and keep more drugs in the skin compared with conventional gel formulations. In vivo study showed that liposomal gel was more effective than conventional gel in treating psoriasis and had a significant dose-dependent effect on psoriasis. In summary, liposomal gel is expected to be an ideal carrier for topical drug delivery systems of ZTO and TRE.

Potential application of liposomal nanodevices for non-cancer diseases: an update on design, characterization and biopharmaceutical evaluation

Liposomes, lipid-based vesicular systems, have attracted major interest as a means to improve drug delivery to various organs and tissues in the human body. Recent literature highlights the benefits of liposomes for use as drug delivery systems, including encapsulating of both hydrophobic and hydrophilic cargos, passive and active targeting, enhanced drug bioavailability and therapeutic effects, reduced systemic side effects, improved cargo penetration into the target tissue and triggered contents release. Pioneering work of liposomes researchers led to introduction of long-circulating, ligand-targeted and triggered release liposomes, as well as, liposomes containing nucleic acids and vesicles containing combination of cargos. Altogether, these findings have led to widespread application of liposomes in a plethora of areas from cancer to conditions such as cardiovascular, neurologic, respiratory, skin, autoimmune and eye disorders. There are numerous review articles on the application of liposomes in treatment of cancer, which seems the primary focus, whereas other diseases also benefit from liposome-mediated treatments. Therefore, this article provides an illustrated detailed overview of liposomal formulations, in vitro characterization and their applications in different disorders other than cancer. Challenges and future directions, which must be considered to obtain the most benefit from applications of liposomes in these disorders, are discussed.

Targeted Topical Delivery of Retinoids in the Management of Acne Vulgaris: Current Formulations and Novel Delivery Systems

Acne vulgaris is a common inflammatory pilosebaceous condition that affects 80-90% of adolescents. Since the introduction of tretinoin over 40 years ago, topical retinoid products have been a mainstay of acne treatment. The retinoids are very effective in addressing multiple aspects of the acne pathology as they are comedolytic and anti-inflammatory, and do not contribute to antibiotic resistance or microbiome disturbance that can be associated with long-term antibiotic therapies that are a common alternative treatment. However, topical retinoids are associated with skin dryness, erythema and pain, and may exacerbate dermatitis or eczema. Thus, there is a clear need to target delivery of the retinoids to the pilosebaceous units to increase efficacy and minimise side effects in surrounding skin tissue. This paper reviews the current marketed topical retinoid products and the research that has been applied to the development of targeted topical delivery systems of retinoids for acne.

Oleic Acid Nanovesicles of Minoxidil for Enhanced Follicular Delivery

Current topical minoxidil (MXD) formulations involve an unpleasant organic solvent which causes patient incompliance in addition to side effects in some cases. Therefore, the objective of this work was to develop an MXD formulation providing enhanced follicular delivery and reduced side effects. Oleic acid, being a safer material, was utilized to prepare the nanovesicles, which were characterized for size, entrapment efficiency, polydispersity index (PDI), zeta potential, and morphology. The nanovesicles were incorporated into the emugel Sepineo^® P 600 (2% w/v) to provide better longer contact time with the scalp and improve physical stability. The formulation was evaluated for in vitro drug release, ex vivo drug permeation, and drug deposition studies. Follicular deposition of the vesicles was also evaluated using a differential tape stripping technique and elucidated using confocal microscopy. The optimum oleic acid vesicles measured particle size was 317 ± 4 nm, with high entrapment efficiency (69.08 ± 3.07%), narrow PDI (0.203 ± 0.01), and a negative zeta potential of −13.97 ± 0.451. The in vitro drug release showed the sustained release of MXD from vesicular gel. The skin permeation and deposition studies revealed superiority of the prepared MXD vesicular gel (0.2%) in terms of MXD deposition in the stratum corneum (SC) and remaining skin over MXD lotion (2%), with enhancement ratios of 3.0 and 4.0, respectively. The follicular deposition of MXD was 10-fold higher for vesicular gel than the control. Confocal microscopy also confirmed the higher absorption of rhodamine via vesicular gel into hair follicles as compared to the control. Overall, the current findings demonstrate the potential of oleic acid vesicles for effective targeted skin and follicular delivery of MXD.

Selective delivery of adapalene to the human hair follicle under finite dose conditions using polymeric micelle nanocarriers

Drug delivery systems that target the pilosebaceous unit (PSU) selectively could improve the clinical management of diseases that originate in the hair follicle. The aims of this study were (i) to prepare polymeric micelles using d-α-tocopheryl polyethylene glycol succinate diblock copolymer that incorporated adapalene (ADA), a retinoid indicated for Acne vulgaris, and (ii) to investigate the feasibility of delivering ADA preferentially to the PSU under finite dose conditions - thereby better approximating actual conditions of use by patients. Incorporation of ADA into spherical micelles (d_n <20 nm) increased aqueous solubility by ∼50 000-fold (from <4 ng mL^-1 to 0.2 mg mL^-1). Optimized micelle solution and gel formulations (0.02% ADA) were stable after storage for 4 weeks at 4 °C. Finite dose experiments using full-thickness porcine and human skin revealed that ADA delivery efficiency from micelle solution and gel formulations was equivalent and was >2- and 10-fold higher than that from Differin® gel and Differin® cream (products containing ADA at 0.1% (w/w)). Follicular delivery studies in human skin, using a punch biopsy technique to extract the intact PSU, demonstrated that the micelle solution and gel formulations did indeed enable preferential delivery of ADA to the PSU (4.5- and 3.3-fold higher, respectively, than that to PSU-free skin biopsies). Confocal laser scanning microscopy provided visual corroboration that ADA was uniformly distributed in the hair follicles. In conclusion, the results confirmed that polymeric micelle nanocarriers enabled selective, targeted drug delivery to the PSU under finite dose conditions and so might improve therapy of follicular diseases and decrease off-site side-effects.