Controlled drug delivery for alopecia: A review

Non-Cicatricial Alopecia and Its Association with Anthropometric Measurements and Nutritional Laboratory Markers

Alopecia constitutes one of the most common dermatological disorders, and its steadily increasing prevalence is a cause for concern. Alopecia can be divided into two main categories, cicatricial/scarring and non-cicatricial/non-scarring, depending on the causes of hair loss and its patterns. The aim of this study was to investigate the relationship between anthropometric and nutritional laboratory parameters in Caucasian adult women and men with non-cicatricial alopecia. A total of 50 patients (37 with non-cicatricial alopecia and 13 healthy controls) were included in the study. Clinical examination and scalp trichoscopy were performed. The anthropometric and nutritional laboratory parameters were collected and analyzed. No statistically significant differences in the laboratory findings were found. The patients with non-cicatricial alopecia were statistically significantly younger as compared to the controls. An elevated risk of hair loss, which was detected among the younger participants, might be associated with a modern lifestyle and the so-called 'Western diet'. It seems safe to assume that suboptimal nutrition and poor eating habits during childhood might constitute risk factors for early hair loss.

Microneedle Delivery Platform Integrated with Codelivery Nanoliposomes for Effective and Safe Androgenetic Alopecia Treatment

Although topical application of minoxidil is a widely used, FDA-approved therapy for androgenetic alopecia (AGA) treatment, it suffers from low bioavailability, the requirement for frequent long-term use, and side effects. With a similar structure as minoxidil, kopexil and kopyrrol are less toxic and have been commercialized, but show an inferior hair regeneration effect compared to minoxidil. Herein, we developed a hyaluronic acid (HA)-based dissolvable microneedles (MNs) delivery platform integrated with kopexil and kopyrrol coencapsulated nanoliposomes (KK-NLPs) to effectively and safely treat AGA. Facilitated by nanoliposomes and MNs, the encapsulated KK-NLPs performed efficient skin penetration and enhanced cellular internalization into human dermal papilla cells. Furthermore, within the target cells, the codelivered kopexil and kopyrrol show synergistic effects by orchestrating an upregulation in the expression of Ki67, β-catenin, vascular endothelial growth factor (VEGF), and CD31. These molecular responses collectively foster cell proliferation, migration, and antioxidative effects, thereby facilitating the expedited progression of hair follicles (HFs) into the anagen phase and promoting peripheral angiogenesis. Notably, the KK-NLPs-integrated MNs treatment group exhibits noteworthy enhanced hair regeneration in vivo, with identical or superior therapeutic effects at a much lower dosage than that of minoxidil. These results suggest the great potential of this kopexil and kopyrrol codelivery nanoliposomes-integrated MNs platform for AGA treatment in a safe and efficient way.

Optimization of hair follicle spheroids for hair-on-a-chip

Currently, most models for hair follicle research have the limitation of not replicating some key features of the hair follicle microenvironment. To complement this, we transfected various factors for hair growth into dermal papilla cells (DPCs) by electroporation and cultured the spheroids with keratinocytes (KCs). We optimized the cell number and culture period for applying spheroids to hair-on-a-chip. Furthermore, we investigated the expression of hair growth factors in spheroids depending on the presence or absence of human umbilical vein endothelial cells (HUVECs) and transfection. In spheroids in which DPCs, KCs, and HUVECs were co-cultured for 21 days, the expression of lymphoid enhancer factor 1 (LEF1), T-cell factor 1 (TCF1), and keratin 25 (K25) in the center of the spheroid, the expression of keratin 17 (K17) on the outer surface of the spheroid, and the shape of hair extending outward from the spheroid surface were observed. From these results, it is expected that a hair-on-a-chip experiment in which short-term cultured TKH spheroids are injected into the dermis and co-cultured with KC will enable the production of full-thickness skin equivalents containing hair in vitro without transplantation into animals.

Thermodynamically stable ionic liquid microemulsions pioneer pathways for topical delivery and peptide application

Copper peptides (GHK-Cu) are a powerful hair growth promoter with minimal side effects when compared with minoxidil and finasteride; however, challenges in delivering GHK-Cu topically limits their non-invasive applications. Using theoretical calculations and pseudo-ternary phase diagrams, we designed and constructed a thermodynamically stable ionic liquid (IL)-based microemulsion (IL-M), which integrates the high drug solubility of ILs and high skin permeability of microemulsions, thus improving the local delivery of copper peptides by approximately three-fold while retaining their biological function. Experiments in mice validated the effectiveness of our proposed IL-M system. Furthermore, the exact effects of the IL-M system on the expression of growth factors, such as vascular endothelial growth factor, were revealed, and it was found that microemulsion increased the activation of the Wnt/β-catenin signaling pathway, which includes factors involved in hair growth regulation. Overall, the safe and non-invasive IL microemulsion system developed in this study has great potential for the clinical treatment of hair loss.

An Update on Alopecia and its Association With Thyroid Autoimmune Diseases

Alopecia is comorbid with several illnesses, including various autoimmune conditions such as thyroid disease. Leukocyte-mediated inflammation of hair follicles in alopecia was first described over a century ago. However, the high prevalence of the role of thyroid autoimmune disease in the pathogenesis of alopecia has only recently come to light, together with a strong association between the two. Therefore, this review focuses on articles published between 2011 and 2022 on alopecia's association with thyroid autoimmune disease, and the mechanism behind it. In addition, it highlights the link between alopecia and thyroid cancer, as patients with alopecia have increased risk of thyroid cancer. In conclusion, this comprehensive, focused, scoping review will serve as a reference highlighting recent information on alopecia, exploring its association with thyroid autoimmune diseases.

First evidence of the incorporation of daprodustat and other hypoxia-inducible factor stabilizers into equine hair by passive transfer based on segmental quantitative analysis

Daprodustat is a hypoxia-inducible factor prolyl hydroxylase domain (HIF-PHD) inhibitor and is used as an erythropoiesis stimulant for the treatment of anemia in humans. In general, administering daprodustat to horses will result in a lifetime ban from both equestrian sports and horseracing by the International Federation of Horseracing Authorities and the Fédération Équestre Internationale, respectively. To control the misuse/abuse of daprodustat, we conducted nasoesophageal administration of daprodustat (100 mg/day for 3 days) to three thoroughbred mares and the post-administration hair samples collected from the three horses over 6 months were analyzed to demonstrate the potential longer-term detection of daprodustat and its metabolites in hair compared with the detection times of daprodustat of 1 and 2 weeks in plasma and urine respectively. The results of the quantitative 2-cm segmental analysis showed that daprodustat was primarily localized in the proximal region (0-2 cm) at 0.375-0.463 pg/mg at 1 month post-administration. These drug bands were gradually spread out along the hair shaft at a rate consistent with the reported growth rate of horse mane hair (approximately 2.5 cm/month) over the following 6 months. In addition, to attain deeper insight into the mechanism of drug incorporation into hair, a total of 11 relevant parameters, including the actual PK parameters and simulated physicochemical and biopharmaceutical parameters for three HIF stabilizers (i.e., daprodustat, vadadustat, and IOX4), were investigated after normalization of the z-scores of all these parameters. Multiple regression analysis indicated that the major factors contributing to the incorporation of the three drugs into hair were their maximum plasma concentrations and lipophilicities, strongly suggesting that the three HIF stabilizers permeated from the bloodstream into the hair bulb via passive transfer with concentration gradients. This work is the first reported evidence showing the incorporation of HIF stabilizers into hair via passive transfer. In addition, cross-species comparison of drug incorporations into hair between daprodustat in horse and roxadustat in human was made in order to have a better understanding of the interactive interpretations about the analysis results obtained from different species. The above findings are not only useful and beneficial for the purpose of doping control but also provide a better understanding of the mechanism of drug incorporation into horse hair.

Segmental analysis and long-term monitoring of vadadustat in equine hair for the purpose of doping control

Vadadustat is a newly launched hypoxia-inducible factor stabilizer with anti-anemia and erythropoietic effects; however, its use in horses is expressly forbidden in both racing and equestrian competitions. Following our previous report on the pharmacokinetic study of vadadustat in horse plasma and urine, a long-term longitudinal analysis of vadadustat in horse hair after nasoesophageal administration (3 g/day for 3 days) to three thoroughbred mares is described in this study. Our main objective is to further extend the detection period of vadadustat for the purpose of doping control. Three bunches of mane hair from each horse were collected at 0 (pre), 1, 2, 3 and 6 month(s) post-administration. These hair samples were each cut into 2-cm segments and pulverized after decontamination of hair samples. The analyte in the powdered hair samples was extracted with liquid-liquid extraction followed by further purification by solid-phase extraction with strong anion exchange columns. The amount of vadadustat incorporated into the hair was quantified with a newly developed and validated method using liquid chromatography-high-resolution mass spectrometry. Our results show that vadadustat was confirmed in all post-administration hair samples, but its metabolites were not present. Thus, the detection window for vadadustat could be successfully extended up to 6 months post-administration. Interestingly, the 2-cm segmental analysis revealed that the tip of the drug band in the hair shifted along with the hair shafts in correspondence with the average hair growth rate (∼2.5 cm/month) but gradually diffused more widely from 2 cm at 1 month post-administration to up to 14 cm at 6 months post-administration. However, the loss in the total amount of vadadustat in hair over time was observed to most likely be due to the degradation of vadadustat. These findings will be useful for the control of abuse and/or misuse of vadadustat and the interpretation of positive doping cases.

Dissolving microneedles for alopecia treatment

Alopecia is a treatable benign disease, however, approximately 15-30% of women and 50% of men suffer from alopecia, which greatly affects patient's self-esteem and quality of life. Currently, commercial products for alopecia treatment include topical minoxidil solution, oral finasteride tablets and oral baricitinib tablets. However, the barrier of stratum corneum, systemic adverse effects and poor cure rate limit the application of commercial products. Therefore, researchers investigated the mechanism of alopecia, and developed new drugs that could target lactate dehydrogenase-related pathways, remove excessive reactive oxygen in hair follicles, and reduce the escape of hair follicle stem cells, thus injecting new strength into the treatment of alopecia. Moreover, starting from improving drug stratum corneum penetration and reducing side effects, researchers have developed hair loss treatment strategies based on dissolved microneedles (MNs), such as drug powders/microparticles, nanoparticles, biomimetic cell membranes, phototherapy and magnetically responsive soluble microneedles, which show exciting alopecia treatment effects. However, there are still some challenges in the practical application of the current alopecia treatment strategy with soluble microneedles, and further studies are needed to accelerate its clinical translation.

Selective Delivery of Tofacitinib Citrate to Hair Follicles Using Lipid-Coated Calcium Carbonate Nanocarrier Controls Chemotherapy-Induced Alopecia Areata

Chemotherapy-induced alopecia (CIA) is one of the common side effects in cancer treatment. The psychological distress caused by hair loss may cause patients to discontinue chemotherapy, affecting the efficacy of the treatment. The JAK inhibitor, Tofacitinib citrate (TFC), showed huge potential in therapeutic applications for treating baldness, but the systemic adverse effects of oral administration and low absorption rate at the target site limited its widespread application in alopecia. To overcome these problems, we designed phospholipid-calcium carbonate hybrid nanoparticles (PL/ACC NPs) for a topical application to target deliver TFC. The results proved that PL/ACC-TFC NPs showed excellent pH sensitivity and transdermal penetration in vitro. PL/ACC NPs offered an efficient follicular targeting approach to deliver TFC in a Cyclophosphamide (CYP)-induced alopecia areata mouse model. Compared to the topical application of TFC solution, PL/ACC-TFC NPs significantly inhibited apoptosis of mouse hair follicles and accelerated hair growth. These findings support that PL/ACC-TFC NPs has the potential for topical application in preventing and mitigating CYP-induced Alopecia areata.

Enhanced Skin Permeation and Controlled Release of β-Sitosterol Using Cubosomes Encrusted with Dissolving Microneedles for the Management of Alopecia

The use of synthetic medication for treating alopecia is restricted because of systemic exposure and related negative effects. Beta-sitosterol (β-ST), a natural chemical, has lately been studied for its potential to promote hair development. The cubosomes with dissolving microneedles (CUBs-MN_D) created in this study may be a useful starting point for the creation of a sophisticated dermal delivery system for β-ST. Cubosomes (CUBs) were prepared by the emulsification method, using glyceryl monooleate (GMO) as a lipid polymer. CUBs were loaded with dissolving microneedles (MN_D) fabricated with HA and a PVP-K90 matrix. An ex vivo skin permeation study and an in vivo hair growth efficacy test of β-ST were performed with both CUB and CUB-MN_D. The average particle size of the CUBs was determined to be 173.67 ± 0.52 nm, with a low polydispersity index (0.3) and a high zeta potential value that prevents the aggregate formation of dispersed particles. When compared to CUBs alone, CUBs-MN_D displayed higher permeating levels of β-ST at all-time points. In the animals from the CUB-MN_D group, significant hair development was observed. According to the results of the current investigation, CUBs that integrate dissolving microneedles of β-ST are superior in terms of transdermal skin penetration and activity for the treatment of alopecia.

Microneedle system for tissue engineering and regenerative medicine

Global increasing demand for high life quality and length facilitates the development of tissue engineering and regenerative medicine, which apply multidisciplinary theories and techniques to achieve the structural reconstruction and functional recovery of disordered or damaged tissues and organs. However, the clinical performances of adopted drugs, materials, and powerful cells in the laboratory are inescapably limited by the currently available technologies. To tackle the problems, versatile microneedles are developed as the new platform for local delivery of diverse cargos with minimal invasion. The efficient delivery, as well as painless and convenient procedure endow microneedles with good patient compliance in clinic. In this review, we first categorize different microneedle systems and delivery models, and then summarize their applications in tissue engineering and regenerative medicine mainly involving maintenance and rehabilitation of damaged tissues and organs. In the end, we discuss the advantages, challenges, and prospects of microneedles in depth for future clinical translations.

Enhanced skin penetration of Finasteride loaded DMSO-liposomes for the treatment of androgenic alopecia: comparison with conventional liposomes

Long-term treatment with finasteride (FIN) for androgenic alopecia is restricted due to its systemic side effects. To address this problem, DMSO-modified liposomes were prepared in the present study to improve the topical delivery of FIN. DMSO-liposomes were prepared by a modification of the ethanol injection method. It was hypothesized that the permeation-enhancing property of DMSO could promote drug delivery to deeper skin layer where hair follicles are present. Liposomes were optimized by quality by design (QbD) approach and biologically evaluated in a rat model of testosterone-induced alopecia. Optimized DMSO-liposomes were spherical and had mean vesicle size, zeta potential, and entrapment efficiency of 330.1 ± 1.5, -14.52 ± 1.32, and 59.02 ± 1.12%, respectively. Biological evaluation on testosterone-induced alopecia and skin histology shows that follicular density and anagen/telogen (A/T) ratio were increased in rats treated with DMSO-liposomes as compared to FIN-liposomes without DMSO and an alcoholic solution of FIN applied topically. DMSO-liposomes could be promising skin delivery vehicles for FIN or similar drugs.

Advances in microneedles research based on promoting hair regrowth

Alopecia is the most common and difficult-to-treat hair disorder. It usually brings a significant psychological burden to the patients. With the growing popularity of alopecia, the study of alopecia has gained more attention. Currently, only minoxidil and finasteride have been approved by the FDA for the treatment of alopecia, but the efficacy has always been unsatisfactory. As a new form of transdermal drug delivery, microneedles have been widely used in the treatment of alopecia and have proven to be effective. Microneedles delivery can improve the efficiency of local drug delivery and patients' compliance, which can achieve better therapeutic effects on hair-related diseases. Therefore, microneedles have gained much attention in the field of alopecia and hair regrowth promotion in recent years. This review summarizes the last decade of research on the microneedles delivery design for the treatment of alopecia or promotion of hair regrowth and provides a comprehensive evaluation of this field.

An integrative analysis of the lncRNA-miRNA-mRNA competitive endogenous RNA network reveals potential mechanisms in the murine hair follicle cycle

Alopecia is a common progressive disorder associated with abnormalities of the hair follicle cycle. Hair follicles undergo cyclic phases of hair growth (anagen), regression (catagen), and rest (telogen), which are precisely regulated by various mechanisms. However, the specific mechanism associated with hair follicle cycling, which includes noncoding RNAs and regulation of competitive endogenous RNA (ceRNA) network, is still unclear. We obtained data from publicly available databases and performed real-time quantitative polymerase chain reaction validations. These analyses revealed an increase in the expression of miRNAs and a decrease in the expression of target mRNAs and lncRNAs from the anagen to telogen phase of the murine hair follicle cycle. Subsequently, we constructed the ceRNA networks and investigated their functions using enrichment analysis. Furthermore, the androgenetic alopecia (AGA) microarray data analysis revealed that several novel alopecia-related genes were identified in the ceRNA networks. Lastly, GSPT1 expression was detected using immunohistochemistry. Our analysis revealed 11 miRNAs (miR-148a-3p, miR-146a-5p, miR-200a-3p, miR-30e-5p, miR-30a-5p, miR-27a-3p, miR-143-3p, miR-27b-3p, miR-126a-3p, miR-378a-3p, and miR-22-3p), 9 target mRNAs (Atp6v1a, Cdkn1a, Gadd45a, Gspt1, Mafb, Mitf, Notch1, Plk2, and Slc7a5), and 2 target lncRNAs (Neat1 and Tug1) were differentially expressed in hair follicle cycling. The ceRNA networks were made of 12 interactive miRNA-mRNA pairs and 13 miRNA-lncRNA pairs. The functional enrichment analysis revealed the enrichment of hair growth–related signaling pathways. Additionally, GSPT1 was downregulated in androgenetic alopecia patients, possibly associated with alopecia progression. The ceRNA network identified by our analysis could be involved in regulating the hair follicle cycle.

Clinicopathological Features of Alopecia With an Emphasis on Etiology and Histopathological Characteristics of Scarring Alopecia

Introduction

Alopecia is a common dermatological condition with varied etiologies based on age, gender and geographic location. Non-cicatricial (non-scarring) alopecia is more common but often not biopsied. Alternatively, primary cicatricial (scarring) alopecia is diagnostically more challenging and more commonly biopsied to determine the etiology. In this study, we evaluated the clinicopathological characteristics of alopecia in our population.

Methods

We conducted a retrospective study at the Department of Histopathology, Liaquat National Hospital and Medical College, Pakistan. A total of 104 patients were enrolled in the study who underwent scalp biopsy for alopecia over a period of 11 years. Clinical data were obtained from clinical referral forms, which included age, sex of the patients and duration of the lesions. Three hematoxylin and eosin-stained tissue sections, along with periodic acid-Schiff (PAS), PAS with diastase and collagen stains were examined, and histopathological diagnosis was rendered.

Results

Our study demonstrated that alopecia was more prevalent among females, accounting for 73.1% of cases. Most of the patients belonged to the age group of <35 years (53.8%). The type of alopecia in 88.5% of the cases was scarring, while there were 11.5% cases of non-scarring alopecia. The most common diagnoses were discoid lupus erythematosus (DLE) (23.1%) and pseudopelade of Brocq (PB) (23.1%), followed by lichen planopilaris (LPP) (15.4%). A significant association was noted between the histological features and the diagnosis, as epidermal atrophy was the most common histological feature in most cases of DLE, followed by periadnexal infiltrates, lymphocytic infiltrates, follicular plugging and basement membrane thickening. In LPP, the most common histological features were perifollicular infiltrates and fibrosis. In PB, the frequently recurring histological features in most cases were the loss of sebaceous glands, dermal fibrosis and epidermal thinning.

Conclusion

In this study, we demonstrated the key role of skin punch biopsy and histology in determining the accurate etiology of scarring alopecia. We found discoid lupus erythematosus and pseudopelade of Brocq to be the most common causes of scarring alopecia, followed by lichen planopilaris.

Long-term monitoring of IOX4 in horse hair and its longitudinal distribution with segmental analysis using liquid chromatography/electrospray ionization Q Exactive high-resolution mass spectrometry for the purpose of doping control

IOX4, a hypoxia-inducible factor stabilizer, is classified as a banned substance for horses in both horse racing and equestrian sports. We recently reported the pharmacokinetic profiles of IOX4 in horse plasma and urine and also identified potential monitoring targets for the doping control purpose. In this study, a long-term longitudinal analysis of IOX4 in horse hair after a nasoesophageal administration of IOX4 (500 mg/day for three days) to three thoroughbred mares is presented for the first time for controlling the abuse/misuse of IOX4. Six bunches of mane hair were collected at 0 (pre), 1, 2, 3, and 6 month(s) post-administration. Our results showed that the presence of IOX4 was identified in all post-administration horse hair samples but no metabolite could be detected. The detection window for IOX4 could achieve up to 6-month post-administration (last sampling point) by monitoring IOX4 in hair. In order to evaluate the longitudinal distribution of IOX4 over six months, a validated quantification method of IOX4 in hair was developed for the analysis of the post-administration samples. Segmental analysis of 2-cm cut hair across the entire length of post-administration hair showed that IOX4 could be quantified up to the level of 1.84 pg/mg. In addition, it was found that the movement of the incorporated IOX4 band in the hair shaft over six months varied among the three horses due to individual variation and a significant diffusion of IOX4 band up to 10 cm width was also observed in the 6-month post-administration hair samples.

Mapping hair follicle-targeted delivery by particle systems: What has science accomplished so far?

The importance of the hair follicle in the process of cutaneous drug penetration has been established since this skin appendage was recognized as an entry point for topically applied substances. A comprehensive review on the hair follicle as a target per se is here provided, exploring the current knowledge on both targeted regions and delivery systems that take advantage of this permeation route. The follicular penetration is a complex process, whose effectiveness and efficiency strongly depends on a diversity of different factors including follicular density and size, activity status of hair follicles and physicochemical properties of the topically applied substances. Nanocarriers represent a heterogeneous assembly of molecules organized into particles and they have revolutionized drug delivery in several areas of medicine, pharmacology and cosmetics. As they possess an inherent ability to use the follicular route, they are reviewed here having in perspective the hair follicle zones that they are able to reach as reported. In this way, a follicular road map for the different delivery systems was compiled to assist as a guiding tool for those that have interest in the development and/or application of such delivery systems for hair and skin treatment or care.

Ethyl cellulose coated sustained release aspirin spherules for treating COVID-19: DOE led rapid optimization using arbitrary interface; applicable for emergency situations

This work attempts to resolve one of the key issues related to the design and development of sustained-release spherule of aspirin for oral formulations, tailored to treat COVID-19. For that, in the Design of Experiments (DOE) an arbitrary interface, "coating efficiency" (CE) is introduced and scaled the cumulative percentage coating (CPC) to get predictable control over drug release (DR). Subsequently, the granules containing ASP are converted to spherules and then to Ethyl cellulose (EC) Coated spherules (CS) by a novel bed coating during the rolling (BCDR) process. Among spherules, one with 0.35 mm than 0.71 mm shows required properties. The CS has a low 120⁰ angle by Optical Microscopy (OM), smooth surface without cracks by scanning electron microscopy (SEM), and better flow properties (Angle of repose 29.69 ± 0.78⁰, Carr's index 6.73 ± 2.24%, Hausner's Ratio 1.07 ± 0.03) than granules and spherules. Once certain structure-dependent control over release is attained (EC coated spherules shows 10% reduction in burst release (BR) than uncoated spherules showing a release of 80-91%) the predictability is achieved and Design of space (DOS) by DOE (CE-70.14%and CPC-200% and DR-61.54%) is established. The results of DOE to experimentally validated results were within 20% deviation. The aspirin is changing its crystal structure by powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) from Form-I to Form-II showing polymorphism inside the drug reservoir with respect to the process. This CE and CPC approach in DOE can be used for delivery system design of other labile drugs similar to aspirin in emergency situations.

Topical Treatment for Scarring and Non-Scarring Alopecia: An Overview of the Current Evidence

Alopecia is a clinical condition related to hair loss that can significantly affect both male and female adults' quality of life. Despite the high market demand, only few drugs are currently approved for alopecia treatment. Topical formulations still bring drawbacks, such as scalp irritation with frequent use, and low drug absorption to the site of action, which limits the efficacy. The most recent research points out that different formulation technology could circumvent the aforementioned flaws. Such technology includes incorporation of drugs in rigid or deformable nanoparticles, strategies involving physical, energetical and mechanical techniques, such as iontophoresis, sonophoresis, microneedling, and the use of solid effervescent granules to be hydrated at the moment of application in the scalp. In this paper, the progress of current research on topical formulations dedicated to the treatment of alopecia is reviewed and discussed.

Microemulsions as Solubilizers and Penetration Enhancers for Minoxidil Release from Gels

Micro- and nanoemulsions are potential drug solubilizers and penetration enhancers through the high surfactant/co-surfactant content. This study aimed to evaluate the influence of minoxidil (MXD) solubilized in the microemulsions (MEs) on drug release by in vitro/ex vivo diffusion through the semi-permeable membrane Spectra/Por^® (Spectrum Laboratory, Gardena, CA, USA) and porcine ear skin. Moreover, a residual amount of drug in the skin after ex vivo diffusion was evaluated. The reference ME_R, lecithin-containing ME_L, and gelatin-containing ME_G were characterized in terms of their size, polydispersity index, density, viscosity, electrical conductivity and surface tension. Based on the in vitro diffusion, it can be argued that ME_L slowed down the drug release, while ME_R and ME_G have no significant effect compared to the sample, in which propylene glycol (PG) was used as a solubilizer. Determination of the residual drug amount in the skin after 6 h of the ex vivo permeation was demonstrated as the most valuable method to evaluate the effectiveness of the ME’s application. The results indicate that the most optimal MXD permeation enhancers in alginate gel were the natural surfactants containing MEs. MXD solubilization in ME_G and ME_L had caused more than 5% of the drug remaining in the skin, which is almost a 1.5-fold higher amount compared to the reference gel.

Thiolated and PEGylated silica nanoparticle delivery to hair follicles

Targeting drug delivery to hair follicles is valuable to treat conditions such as alopecia's and acne, and this shunt route may also allow drug delivery to deeper skin layers and the systemic circulation by avoiding the intact stratum corneum. Here, we investigated the effects of nanoparticle surface chemistry on their delivery into hair follicles by synthesizing fluorescent thiolated silica nanoparticles and functionalizing with 750 Da and 5000 Da methoxypolyethylene glycol maleimide (PEG). The stability of the nanoparticles in skin homogenate was verified before tape stripping of porcine-dosed tissue showed the distribution of the free fluorescent dye and different nanoparticles in the skin. Analysis of microscopic images of the skin sections revealed penetration of nanoparticles functionalized with PEG into the appendages whereas thiolated nanoparticles stayed on the surface of the skin and were removed by tape stripping. Nanoparticles functionalized with PEG 5000 Da penetrated deeper into the hair follicles compared to counterparts functionalized with PEG 750 Da. PEGylation can thus enhance targeted delivery of nanoparticulates into hair follicles.

Drug delivery to optimize angiogenesis imbalance in keloid: A review

The wound healing process involves three continuous stages. Where, any imbalance can lead to the formation of unwanted keloids, hypertrophic scar, or tumors. Keloids are any unpleasant, non-compliant comorbidity affecting a major section of people around the globe who acquire it either genetically or by pathological means as a result of a skin injury. Angiogenesis is unavoidable in the healing process after an injury or disruption of skin to promote tissue regeneration. Uncontrolled angiogenesis during the healing process can initiate the unwanted response in the wound that facilitate keloid. Angiogenic therapy is adapted to accelerate healing after an injury. Else ways, there exists a risk of keloid formation due to excessive angiogenesis during the wound healing process. There are numerous strategies to treat keloid. Anti-angiogenic factors are provided to patients post-surgery to prevent the keloid formation; however, they come into the picture after the formation of keloid. The available strategies to treat keloids are steroidal injections, surgical excision of the keloid, radiotherapy, pressure therapy, the use of cryosurgery, and many more. The available treatments are not promising in reducing the recurrent rate of keloids as there are chances of high re-occurrences with similar/larger lesions on the removed keloid site. In this review, we are discussing the importance of controlled angiogenesis with the help of controlled drug delivery strategies enabling the wound healing process without the induction of keloid.