Topical Administration of Drugs Incorporated in Carriers Containing Phospholipid Soft Vesicles for the Treatment of Skin Medical Conditions

A review on natural biopolymers in external drug delivery systems for wound healing and atopic dermatitis

Despite the advantages of topical administration in the treatment of skin diseases, current marketed preparations face the challenge of the skin's barrier effect, leading to low therapeutic effectiveness and undesirable side effects. Hence, in recent years the management of skin wounds, the main morbidity-causing complication in hospital environments, and atopic dermatitis, the most common inflammatory skin disease, has become a great concern. Fortunately, new, more effective, and safer treatments are already under development, with chitosan, starch, silk fibroin, agarose, hyaluronic acid, alginate, collagen, and gelatin having been used for the development of nanoparticles, liposomes, niosomes and/or hydrogels to improve the delivery of several molecules for the treatment of these diseases. Biocompatibility, biodegradability, increased viscosity, controlled drug delivery, increased drug retention in the epidermis, and overall mitigation of adverse effects, contribute to an effective treatment, additionally providing intrinsic antimicrobial and wound healing properties. In this review, some of the most recent success cases of biopolymer-based drug delivery systems as part of nanocarriers, semi-solid hydrogel matrices, or both (hybrid systems), for the management of skin wounds and atopic dermatitis, are critically discussed, including composition and in vitro, ex vivo and in vivo characterization, showing the promise of these external drug delivery systems.

The Evolution of Emerging Nanovesicle Technologies for Enhanced Delivery of Molecules into and across the Skin

This review focuses on nanovesicular carriers for enhanced delivery of molecules into and across the skin, from their design to recent emerging technologies. During the last four decades, several approaches have been used aiming to design new nanovesicles, some of them by altering the properties of the classic phospholipid vesicle, the liposome. Phospholipid nanovesicular systems, including the phospholipid soft vesicles as well as the non-phospholipid vesicular carries, are reviewed. The altered nanovesicles have served in the manufacture of various cosmetic products and have been investigated and used for the treatment of a wide variety of skin conditions. The evolution and recent advances of these nanovesicular technologies are highlighted in this review.

Novel Therapeutic Hybrid Systems Using Hydrogels and Nanotechnology: A Focus on Nanoemulgels for the Treatment of Skin Diseases

Topical and transdermal drug delivery are advantageous administration routes, especially when treating diseases and conditions with a skin etiology. Nevertheless, conventional dosage forms often lead to low therapeutic efficacy, safety issues, and patient noncompliance. To tackle these issues, novel topical and transdermal platforms involving nanotechnology have been developed. This review focuses on the latest advances regarding the development of nanoemulgels for skin application, encapsulating a wide variety of molecules, including already marketed drugs (miconazole, ketoconazole, fusidic acid, imiquimod, meloxicam), repurposed marketed drugs (atorvastatin, omeprazole, leflunomide), natural-derived compounds (eucalyptol, naringenin, thymoquinone, curcumin, chrysin, brucine, capsaicin), and other synthetic molecules (ebselen, tocotrienols, retinyl palmitate), for wound healing, skin and skin appendage infections, skin inflammatory diseases, skin cancer, neuropathy, or anti-aging purposes. Developed formulations revealed adequate droplet size, PDI, viscosity, spreadability, pH, stability, drug release, and drug permeation and/or retention capacity, having more advantageous characteristics than current marketed formulations. In vitro and/or in vivo studies established the safety and efficacy of the developed formulations, confirming their therapeutic potential, and making them promising platforms for the replacement of current therapies, or as possible adjuvant treatments, which might someday effectively reach the market to help fight highly incident skin or systemic diseases and conditions.

Capsicum annuum Oleoresin Nanoemulgel - Design Characterization and In vitro Investigation of Anticancer and Antimicrobial Activities

BACKGROUND

The use of naturally occurring bioactive materials is getting great attention owing to their safety and environmental properties. Oily compounds, known as oleoresins, are expected to provide an important source for the natural products industry aiming to develop novel treatments for skin conditions. In this work, Capsicum annuum oleoresin nanoemulgel formulations have been prepared and investigated for their antibacterial and anticancer properties.

METHODOLOGY

Several C. annuum oleoresin nanoemulgel formulations were prepared by incorporating a Carbopol 940 gel in a self-nanoemulsifying nanoemulsion consisting of C. annuum, tween 80, and span 80. The systems were characterized for particle size, polydispersity index (PDI), zeta potential, and rheology. The in vitro antimicrobial and cytotoxic activities of the optimum formulation were evaluated.

RESULTS

The selected formulation is composed of 40% tween, 10% span 80, and 40% C. annuum oleoresin. This formulation produced a stable nanoemulsion with a narrow PDI value of 0.179 ± 0.08 and a droplet size of 104.0 ± 2.6 nm. Results of the in vitro antimicrobial studies indicated high potency of the systems against methicillin-resistant Staphylococcus aureus (MRSA) (zone of inhibition of 29 ± 1.9 mm), E. coli (33 ± 0.9 mm), K. pneumonia (30 ± 1.4 mm), and C. albicans (21 ± 1.5 mm), as compared to the reference antibiotic, ampicillin (18 ± 1.4 mm against K. pneumonia), and antifungal agent, fluconazole (12 ± 0.1 mm against C. albicans). Furthermore, cytotoxicity results, expressed as IC50 values, revealed that the oleoresin and its nanoemulgel had the best effects against the HepG2 cell line (IC50 value of 79.43 μg/mL for the nanoemulgel) and MCF7 (IC50 value of 57.54 μg/mL), and the most potent effect was found against 3T3 (IC50 value of 45.7 μg/m- L). On the other side, the system did not substantially exhibit activity against By-61 and Hela.

CONCLUSION

C. annuum oleoresin and its nanoemulgel can be considered valuable sources for the discovery of new antibacterial, antifungal, and anticancer compounds in the pharmaceutical industry, especially due to their potent activity against various cancer cell lines as well as bacterial and fungal strains.

Deformable Vesicles with Edge Activators for the Transdermal Delivery of Non-Psychoactive Cannabinoids

BACKGROUND

Transdermal delivery of highly lipophilic molecules is challenging due to the strong barrier function of the skin. Vesicles with penetration enhancers are safe and efficient systems that could improve the transdermal delivery of non-psychoactive cannabinoids such as cannabidiol and desoxy-cannabidiol. In the last decades, research interest in desoxy-cannabidiol as a potent drug with anti-nociceptive properties has risen. Still, its scarce market availability poses a limit for both research and clinical applications. Therefore, it is necessary to improve the synthesis to produce sufficient amounts of desoxy-cannabidiol. Moreover, also the formulation aspects for this drug are challenging and require to be addressed to meet an efficient delivery to the patients.

OBJECTIVE

This work aimed to develop innovative phospholipid-based vesicles with propylene glycol (PG), oleic acid (OA), or limonene as edge activators, for the transdermal delivery of highly lipophilic drugs such as non-psychoactive cannabinoids. In particular, desoxy-cannabidiol was selected thanks to its anti-nociceptive activity, and its synthesis was improved enhancing the stereoselectivity of its synthon's production.

METHODS

Desoxy-cannabidiol was synthesized by Lewis acid-mediated condensation of p-mentha-2,8-dien- 1-ol and m-pentylphenol, improving the stereoselectivity of the first synthon's production. Transethosomes containing 20-50% w/w PG, 0.4-0.8% w/w OA, or 0.1-1% w/w limonene were optimized and loaded with cannabidiol or desoxy-cannabidiol (0.07-0.8% w/w, 0.6-7.0 mg/mL). Ex-vivo studies were performed to assess both the skin permeation and accumulation of the cannabinoids, as well as the penetration depth of fluorescein- loaded systems used as models.

RESULTS

An enantioselective bromination was added to the pathway, thus raising the production yield of pmentha- 2,8-dien-1-ol to 81% against 35%, and the overall yield of desoxy-cannabidiol synthesis from 12% to 48%. Optimized transethosomes containing 0.6 mg/mL cannabinoids were prepared with 1:10 PG:lipid weight ratio, 0.54 OA:lipid molar ratio, and 0.3 limonene:lipid molar ratio, showing good nanometric size (208 ± 20.8 nm - 321 ± 26.3 nm) and entrapment efficiency (> 80%). Ex-vivo tests showed both improved skin permeation rates of cannabinoids (up to 21.32 ± 4.27 μg/cm2 cannabidiol), and skin penetration (depth of fluorescein up to 240 μm, with PG).

CONCLUSION

Desoxy-cannabidiol was successfully produced at high yields, and formulated into transethosomes optimized for transdermal delivery. Loaded vesicles showed improved skin penetration of desoxy-cannabidiol, cannabidiol and a lipophilic probe. These results suggest the potential of these carriers for the transdermal delivery of highly lipophilic drugs.

Phytosterol-mediated glycerosomes combined with peppermint oil enhance transdermal delivery of lappaconitine by modulating the lipid composition of the stratum corneum

Although the introduction of glycerosomes has enriched strategies for efficient transdermal drug delivery, the inclusion of cholesterol as a membrane stabilizer has limited their clinical application. The current study describes the development and optimization of a new type of glycerosome (S-glycerosome) that is formed in glycerol solution with β-sitosterol as the stabilizer. Moreover, the transdermal permeation properties of lappaconitine (LA)-loaded S-glycerosomes and peppermint oil (PO)-mediated S-glycerosomes (PO-S-glycerosomes) are evaluated, and the lipid alterations in the stratum corneum are analyzed via lipidomics. The LA-loaded S-glycerosomes prepared by the preferred formulation from the uniform design have a mean size of 145.3 ± 7.81 nm and an encapsulation efficiency of 73.14 ± 0.35%. Moreover, the addition of PO positively impacts transdermal flux, peaking at 0.4% (w/v) PO. Tracing of the fluorescent probe P4 further revealed that PO-S-glycerosomes penetrate deeper into the skin than S-glycerosomes and conventional liposomes. Additionally, treatment with PO-S-glycerosomes alters the isoform type, number, and composition of sphingolipids, glycerophospholipids, glycerolipids, and fatty acids in the stratum corneum, with the most notable effect observed for ceramides, the main component of sphingolipids. Furthermore, the transdermal administration of LA-loaded PO-S-glycerosomes improved the treatment efficacy of xylene-induced inflammation in mice without skin irritation. Collectively, these findings demonstrate the feasibility of β-sitosterol as a stabilizer in glycerosomes. Additionally, the inclusion of PO improves the transdermal permeation of S-glycerosomes, potentially by altering the stratum corneum lipids.

Formulation and Characterization of Hesperidin-Loaded Transethosomal Gel for Dermal Delivery to Enhance Antibacterial Activity: Comprehension of In Vitro, Ex Vivo, and Dermatokinetic Analysis

In this study, hesperidin was loaded into a transethosome and was developed employing the rotary evaporator method. The formulation was optimized using the Box-Behnken design (BBD). The optimized HSD-TE formulation has a spherical shape, vesicle size, polydispersity index, entrapment efficiency, and zeta potential within the range of 178.98 nm; the PDI was 0.259 with a zeta potential of -31.14 mV and % EE of 89.51%, respectively. The in vitro drug release shows that HSD-TE exhibited the release of 81.124 ± 3.45% in comparison to HSD suspension. The ex vivo skin permeation showed a 2-fold increase in HSD-TE gel permeation. The antioxidant activity of HSD-TE was found to be 79.20 ± 1.77% higher than that of the HSD solution. The formulation showed 2-fold deeper HSD-TE penetration across excised rat skin membranes in confocal laser microscopy scanning, indicating promising in vivo prospects. In a dermatokinetic study, HSD-TE gel was compared to HSD conventional gel where TE significantly boosted HSD transport in the epidermis and dermal layers. The formulation showed greater efficacy than free HSD in the inhibition of microbial growth, as evidenced by antibacterial activity on the Gram-negative and positive bacteria. These investigations found that the HSD-TE formulation could enhance the topical application in the management of cutaneous bacterial infections.

Ascorbate formulation improves healing efficacy in excisional wound mice model through interplay between pro and anti-inflammatory cytokines and angiogenic markers

BACKGROUND AND OBJECTIVE

Biomedical research in regenerative medicine prompts researchers to formulate cost-effective therapeutics for wound healing. The present study was conducted to characterize the ascorbate based formulation vis-a-vis investigating the molecular dynamics of the formulation.

MATERIALS AND METHODS

To characterize the formulation, particle size, zeta potential, thermal stability, compatibility, anti-oxidant, and permeation prospective were measured using standard protocols. The in-vitro healing potential and safety formulae were evaluated using the L929 cell line. For molecular unravelling of the pharmacodynamics of formulation, an excision wound model was used, and 54 mice were randomly and equally divided into three groups, i.e., untreated, betadine-treated, and formulation-treated, to ascertain the interplay between cytokines and chemokines and their culminative role in the release of growth factors.

RESULTS

The ascorbate formulae were found to be amorphous, biocompatible, safe, and long-lasting, with particle sizes and zeta potentials of 389.7 ± 0.69 nm and -38.1 ± 0.65 mV, respectively, and anti-oxidative potential. An in-vitro study revealed that the formulation has a significant (p<0.05) migration potential and is non-toxic. Expression profiling of TGF-β, FGF-2, VEGF, and collagen III & I showed significant (p<0.05) up-regulation, whereas significant (p<0.05) down-regulation of pro-inflammatory genes like IL-1α, IL-1β, TNF-α, IL-6, and temporal change in CCR-5 was observed in formulae-treated animals as compared to other groups.

CONCLUSION

By up-regulating angiogenic and collagen-promoting growth factor gene expression while down-regulating pro-inflammatory gene expression, ascorbate formulation promotes wound healing via extracellular matrix and granulation tissue deposition with significant improvement in tensile strength.

Ethosomal Gel for Topical Administration of Dimethyl Fumarate in the Treatment of HSV-1 Infections

The infections caused by the HSV-1 virus induce lesions on the lips, mouth, face, and eye. In this study, an ethosome gel loaded with dimethyl fumarate was investigated as a possible approach to treat HSV-1 infections. A formulative study was conducted, evaluating the effect of drug concentration on size distribution and dimensional stability of ethosomes by photon correlation spectroscopy. Ethosome morphology was investigated by cryogenic transmission electron microscopy, while the interaction between dimethyl fumarate and vesicles, and the drug entrapment capacity were respectively evaluated by FTIR and HPLC. To favor the topical application of ethosomes on mucosa and skin, different semisolid forms, based on xanthan gum or poloxamer 407, were designed and compared for spreadability and leakage. Dimethyl fumarate release and diffusion kinetics were evaluated in vitro by Franz cells. The antiviral activity against HSV-1 was tested by plaque reduction assay in Vero and HRPE monolayer cells, while skin irritation effect was evaluated by patch test on 20 healthy volunteers. The lower drug concentration was selected, resulting in smaller and longer stable vesicles, mainly characterized by a multilamellar organization. Dimethyl fumarate entrapment in ethosome was 91% w/w, suggesting an almost total recovery of the drug in the lipid phase. Xanthan gum 0.5%, selected to thicken the ethosome dispersion, allowed to control drug release and diffusion. The antiviral effect of dimethyl fumarate loaded in ethosome gel was demonstrated by a reduction in viral growth both 1 h and 4 h post-infection. Moreover, the patch test demonstrated the safety of the ethosomal gel applied on the skin.

Erythromycin Formulations—A Journey to Advanced Drug Delivery

Erythromycin (ERY) is a macrolide compound with a broad antimicrobial spectrum which is currently being used to treat a large number of bacterial infections affecting the skin, respiratory tract, intestines, bones and other systems, proving great value from a clinical point of view. It became popular immediately after its discovery in 1952, due to its therapeutic effect against pathogens resistant to other drugs. Despite this major advantage, ERY exhibits several drawbacks, raising serious clinical challenges. Among them, the very low solubility in water and instability under acidic conditions cause a limited efficacy and bioavailability. Apart from this, higher doses promote drug resistance and undesirable effects. In order to overcome these disadvantages, during the past decades, a large variety of ERY formulations, including nanoparticles, have emerged. Despite the interest in ERY-(nano)formulations, a review on them is lacking. Therefore, this work was aimed at reviewing all efforts made to encapsulate ERY in formulations of various chemical compositions, sizes and morphologies. In addition, their preparation/synthesis, physico-chemical properties and performances were carefully analysed. Limitations of these studies, particularly the quantification of ERY, are discussed as well.

Dimethyl Fumarate-Loaded Transethosomes: A Formulative Study and Preliminary Ex Vivo and In Vivo Evaluation

In this study, transethosomes were investigated as potential delivery systems for dimethyl fumarate. A formulative study was performed investigating the effect of the composition of transethosomes on the morphology and size of vesicles, as well as drug entrapment capacity, using cryogenic transmission electron microscopy, photon correlation spectroscopy, and HPLC. The stability of vesicles was evaluated, both for size increase and capability to control the drug degradation. Drug release kinetics and permeability profiles were evaluated in vitro using Franz cells, associated with different synthetic membranes. The in vitro viability, as well as the capacity to improve wound healing, were evaluated in human keratinocytes. Transmission electron microscopy enabled the evaluation of transethosome uptake and intracellular fate. Based on the obtained results, a transethosome gel was further formulated for the cutaneous application of dimethyl fumarate, the safety of which was evaluated in vivo with a patch test. It was found that the phosphatidylcholine concentration affected vesicle size and lamellarity, influencing the capacity to control dimethyl fumarate’s chemical stability and release kinetics. Indeed, phosphatidylcholine 2.7% w/w led to multivesicular vesicles with 344 nm mean size, controlling the drug’s chemical stability for at least 90 days. Conversely, phosphatidylcholine 0.9% w/w resulted in 130 nm sized unilamellar vesicles, which maintained 55% of the drug over 3 months. These latest kinds of transethosomes were able to improve wound healing in vitro and were easily internalised by keratinocytes. The selected transethosome gel, loading 25 mg/mL dimethyl fumarate, was not irritant after cutaneous application under occlusion, suggesting its possible suitability in the treatment of wounds caused by diabetes mellitus or peripheral vascular diseases.

Vesicular Nanocarriers for Phytocompounds in Wound Care: Preparation and Characterization

The need to develop wound healing preparations is a pressing challenge given the limitations of the current treatment and the rising prevalence of impaired healing wounds. Although herbal extracts have been used for many years to treat skin disorders, due to their wound healing, anti-inflammatory, antimicrobial, and antioxidant effects, their efficacy can be questionable because of their poor bioavailability and stability issues. Nanotechnology offers an opportunity to revolutionize wound healing therapies by including herbal compounds in nanosystems. Particularly, vesicular nanosystems exhibit beneficial properties, such as biocompatibility, targeted and sustained delivery capacity, and increased phytocompounds’ bioavailability and protection, conferring them a great potential for future applications in wound care. This review summarizes the beneficial effects of phytocompounds in wound healing and emphasizes the advantages of their entrapment in vesicular nanosystems. Different types of lipid nanocarriers are presented (liposomes, niosomes, transferosomes, ethosomes, cubosomes, and their derivates’ systems), highlighting their applications as carriers for phytocompounds in wound care, with the presentation of the state-of-art in this field. The methods of preparation, characterization, and evaluation are also described, underlining the properties that ensure good in vitro and in vivo performance. Finally, future directions of topical systems in which vesicle-bearing herbal extracts or phytocompounds can be incorporated are pointed out, as their development is emerging as a promising strategy.