In vitro skin permeation of artemisone and its nano-vesicular formulations

Multifunctional Deep Eutectic Solvent-Based Microemulsion for Transdermal Delivery of Artemisinin

As a serious public health issue, malaria threatens the health of millions of people. Artemisinin, a gift from traditional Chinese medicine, has been used in the treatment of malaria and has shown good therapeutic efficiency. However, due to its low solubility, poor bioavailability, and short half-life time, some smart delivery strategies are still required. Herein, a multifunctional DES prepared from ibuprofen and menthol was prepared. This DES was shown to efficiently promote the solubility of artemisinin up to 400-fold. Then, it was further applied as the oil phase to construct an O/W microemulsion with the help of Tween-80 + Span-20 mixed surfactants. The prepared microemulsion displayed high efficiency in improving the permeability of artemisinin, which can be ascribed to the presence of the permeation enhancer menthol in DES and the microstructure of the O/W microemulsion. Moreover, the simultaneous permeation of artemisinin and ibuprofen further indicated the potential benefits of the presented formulation in the treatment of malaria. To sum up, the microemulsion based on multifunctional DES presented herein provided an effective method for transdermal delivery of artemisinin.

Biocompatible gliadin-sericin complex colloidal particles used for topical delivery of the antioxidant phloretin

Oxidative stress caused by environmental exposures results in numerous skin diseases. Phloretin (PHL) is often used to relieve various skin symptoms, however, precipitation or crystallization of PHL in aqueous systems limits its ability to diffuse through the stratum corneum, making it difficult to exert effect at the target. To address this challenge, we herein report a method for the generation of core-shell nanostructure (G-LSS) via the growth of sericin crust around gliadin nanoparticle as a topical nanocarrier of PHL to improve its cutaneous bioavailability. Physicochemical performance, morphology, stability, and antioxidant activity of the nanoparticles were characterized. G-LSS-PHL exhibited uniformed spherical nanostructures with the robust encapsulation on PHL (∼90 %). This strategy protected PHL from UV-induced degradation, facilitating to inhibit erythrocyte hemolysis and quench free radicals in a dose-dependent manner. Transdermal delivery experiments and porcine skin fluorescence imaging indicated that G-LSS facilitated the penetration of PHL across the epidermis layer of skin to reach deep-seated sites, and promoted cumulative turnover of PHL with a 2.0-fold increase. Cell cytotoxicity and uptake assay confirmed that as-prepared nanostructure was nontoxic to HSFs, and promoted cellular absorption of PHL. Therefore, this work opened up new promising avenues for developing robust antioxidant nanostructure for topical applications.

Transdermal delivery of artemisinins for treatment of pre-clinical cerebral malaria

Transdermal drug delivery avoids complications related to oral or parenteral delivery - the need for sterility, contamination, gastrointestinal side effects, patient unconsciousness or nausea and compliance. For malaria treatment, we demonstrate successful novel transdermal delivery of artemisone (ART) and artesunate. The incorporation of ART into a microemulsion (ME) overcomes the limitations of the lipophilic drug and provides high transcutaneous bioavailability. ART delivery to the blood (above 500 ng/ml) was proved by examining the sera from treated mice, using a bioassay in cultured Plasmodium falciparum. Skin spraying of ART-ME eliminated P. berghei ANKA in an infected mouse model of cerebral malaria (CM) and prevented CM, even after a late treatment with a relatively small amount of ART (13.3 mg/kg). For comparison, the artesunate (the most used commercial artemisinin) formulation was prepared as ART. However, ART-ME was about three times more efficient than artesunate-ME. The solubility and stability of ART in the ME, taken together with the successful transdermal delivery leading to animal recovery, suggest this formulation as a potential candidate for transdermal treatment of malaria.

Efficient Treatment of Experimental Cerebral Malaria by an Artemisone-SMEDDS System: Impact of Application Route and Dosing Frequency

Artemisone (ART) has been successfully tested in vitro and in animal models against several diseases. However, its poor aqueous solubility and limited chemical stability are serious challenges. We developed a self-microemulsifying drug delivery system (SMEDDS) that overcomes these limitations. Here, we demonstrate the efficacy of this formulation against experimental cerebral malaria in mice and the impact of its administration using different routes (gavage, intranasal delivery, and parenteral injections) and frequency on the efficacy of the treatment. The minimal effective daily oral dose was 20 mg/kg. We found that splitting a dose of 20 mg/kg ART given every 24 h, by administering two doses of 10 mg/kg each every 12 h, was highly effective and gave far superior results compared to 20 mg/kg once daily. We obtained the best results with nasal treatment; oral treatment was ranked second, and the least effective route of administration was intraperitoneal injection. A complete cure of experimental cerebral malaria could be achieved through choosing the optimal route of application, dose, and dosing interval. Altogether, the developed formulation combines easy manufacturing with high stability and could be a successful and very versatile carrier for the delivery of ART in the treatment of human severe malaria.

pH-Responsive Nanostructures Based on Surface Active Fatty Acid-Protic Ionic Liquids for Imiquimod Delivery in Skin Cancer Topical Therapy

For topical treatment of skin cancer, the design of pH-responsive nanocarriers able to selectively release the drug in the tumor acidic microenvironment represents a reliable option for targeted delivery. In this context, a series of newly synthesized surface-active fatty acid-protic ionic liquids (FA-PILs), based on tetramethylguanidinium cation and different natural hydrophobic fatty acid carboxylates, have been investigated with the aim of developing a pH-sensitive nanostructured drug delivery system for cutaneous administration in the skin cancer therapy. The capability of FA-PILs to arrange in micelles when combined with each other and with the non-ionic surfactant d-α-Tocopherol polyethylene glycol succinate (vitamin E TPGS) as well as their ability to solubilize imiquimod, an immuno-stimulant drug used for the treatment of skin cancerous lesions, have been demonstrated. The FA-PILs-TPGS mixed micelles showed pH-sensitivity, suggesting that the acidic environment of cancer cells can trigger nanostructures’ swelling and collapse with consequent rapid release of imiquimod and drug cytotoxic potential enhancement. The in vitro permeation/penetration study showed that the micellar formulation produced effective imiquimod concentrations into the skin exposed to acid environment, representing a potential efficacious and selective drug delivery system able to trigger the drug release in the tumor tissues, at lower and less irritating drug concentrations.

Development of an Oil-in-Water Self-Emulsifying Microemulsion for Cutaneous Delivery of Rose Bengal: Investigation of Anti-Melanoma Properties

The topical delivery route is proposed as an alternative or adjunctive approach to melanoma treatment, since the target site for melanoma treatment-the epidermal basal layer-is potentially accessible by this route. Microemulsion systems are effective delivery vehicles for enhanced, targeted skin delivery. This work investigated the effect of Rose Bengal (RB) and RB-loaded self-emulsifying microemulsions (SEMEs) on growth inhibition of human melanoma and normal skin cell monolayers, the safety of the excipients incorporated in SEMEs on human cell lines, and the in-vitro human skin penetration of RB delivered in SEMEs and control solution. Cellular toxicity was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and the growth inhibitory mechanism of RB was investigated by flow cytometry using PI staining. Unloaded SEMEs caused reduced cellular toxicity compared to the surfactant excipient, Labrasol^®. RB-loaded SEMEs increased cell growth inhibition compared to the RB aqueous solution. Flow cytometry revealed apoptotic cells after treatment with RB-loaded SEMEs, indicating that apoptosis may be one of the mechanisms of cell death. Preliminary results of multiphoton microscopy with fluorescence lifetime imaging (MPM-FLIM) analysis showed deeper penetration with greater skin concentrations of RB delivered from SEMEs compared to the RB aqueous solution. This study highlights the enhanced skin penetration and antimelanoma effects of RB loaded in a SEME system.

Vitamin E TPGS based transferosomes augmented TAT as a promising delivery system for improved transdermal delivery of raloxifene

Raloxifene is commonly used for breast cancer protection. The low bioavailability of raloxifene (2%) is the result of its low solubility and intestinal glucuronidation. The nano-lipid carriers are characterized by small particle size, biocompatibility, and sustainable properties that improve cellular uptake of the loaded drug. The aim of this study was the improvement of raloxifene bioavailability by enhancing its solubility and cellular penetration through formulation of D-α-tocopheryl polyethylene glycol 1000 succinate based transferosomes and augmenting their effect with the cationic cell-penetrating peptide transactivator of transcription of the human immunodeficiency virus. Particle size, zeta potential, and transmission electron microscope investigation of the formed nanocarriers were carried out. Ex vivo raloxifene permeation through rat skin and cell viability studies was investigated. The results of D-α-tocopheryl polyethylene glycol 1000 succinate- transactivator of transcription of the human immunodeficiency virus transferosomes showed an average vesicle size of 96.05 nm with positively charged vesicles 39.4 mV of zeta potential value. The results revealed significant (p < 0.05) enhancement of raloxifene permeation from raloxifene transferosomes- loaded film when compared with raw raloxifene film. IC50 results showed significant improvement of formulated raloxifene cytotoxicity by 1.42-fold in comparison with raw raloxifene against MCF-7 cell lines. The developed raloxifene-transferosomes are considered promising nano-lipid carriers for the enhancement delivery of raloxifene.

Clotrimazole Loaded Ufosomes for Topical Delivery: Formulation Development and In-Vitro Studies

Global incidence of superficial fungal infections caused by dermatophytes is high and affects around 40 million people. It is the fourth most common cause of infection. Clotrimazole, a broad spectrum imidazole antifungal agent is widely used to treat fungal infections. Conventional topical formulations of clotrimazole are intended to treat infections by effective penetration of drugs into the stratum corneum. However, drawbacks such as poor dermal bioavailability, poor penetration, and variable drug levels limit the efficiency. The present study aims to load clotrimazole into ufosomes and evaluate its topical bioavailability. Clotrimazole loaded ufosomes were prepared using cholesterol and sodium oleate by thin film hydration technique and evaluated for size, polydispersity index, and entrapment efficiency to obtain optimized formulation. Optimized formulation was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). Skin diffusion studies and tape-stripping were performed using human skin to determine the amount of clotrimazole accumulated in different layers of the skin. Results showed that the optimized formulation had vesicle size <250 nm with ~84% entrapment efficiency. XRD and DSC confirmed the entrapment of clotrimazole into ufosomes. No permeation was observed through the skin up to 24 h following the permeation studies. Tape-stripping revealed that ufosomes led to accumulation of more clotrimazole in the skin compared to marketed formulation (Perrigo). Overall, results revealed the capability of ufosomes in improving the skin bioavailability of clotrimazole.

Recent advances in non-ionic surfactant vesicles (niosomes): Fabrication, characterization, pharmaceutical and cosmetic applications

Development of nanocarriers for drug delivery has received considerable attention due to their potential in achieving targeted delivery to the diseased site while sparing the surrounding healthy tissue. Safe and efficient drug delivery has always been a challenge in medicine. During the last decade, a large amount of interest has been drawn on the fabrication of surfactant-based vesicles to improve drug delivery. Niosomes are self-assembled vesicular nano-carriers formed by hydration of non-ionic surfactant, cholesterol or other amphiphilic molecules that serve as a versatile drug delivery system with a variety of applications ranging from dermal delivery to brain-targeted delivery. A large number of research articles have been published reporting their fabrication methods and applications in pharmaceutical and cosmetic fields. Niosomes have the same advantages as liposomes, such as the ability to incorporate both hydrophilic and lipophilic compounds. Besides, niosomes can be fabricated with simple methods, require less production cost and are stable over an extended period, thus overcoming the major drawbacks of liposomes. This review provides a comprehensive summary of niosomal research to date, it provides a detailed overview of the formulation components, types of niosomes, effects of components on the formation of niosomes, fabrication and purification methods, physical characterization techniques of niosomes, recent applications in pharmaceutical field such as in oral, ocular, topical, pulmonary, parental and transmucosal drug delivery, and cosmetic applications. Finally, limitations and the future outlook for this delivery system have also been discussed.

Facile Preparation of N-Glycosylated 10-Piperazinyl Artemisinin Derivatives and Evaluation of Their Antimalarial and Cytotoxic Activities

According to the precepts that C-10 amino-artemisinins display optimum biological activities for the artemisinin drug class, and that attachment of a sugar enhances specificity of drug delivery, polarity and solubility so as to attenuate toxicity, we assessed the effects of attaching sugars to N-4 of the dihydroartemisinin (DHA)-piperazine derivative prepared in one step from DHA and piperazine. N-Glycosylated DHA-piperazine derivatives were obtained according to the Kotchetkov reaction by heating the DHA-piperazine with the sugar in a polar solvent. Structure of the D-glucose derivative is secured by X-ray crystallography. The D-galactose, L-rhamnose and D-xylose derivatives displayed IC₅₀ values of 0.58–0.87 nM against different strains of Plasmodium falciparum (Pf) and selectivity indices (SI) >195, on average, with respect to the mouse fibroblast WEHI-164 cell line. These activities are higher than those of the amino-artemisinin, artemisone (IC₅₀ 0.9–1.1 nM). Notably, the D-glucose, D-maltose and D-ribose derivatives were the most active against the myelogenous leukemia K562 cell line with IC₅₀ values of 0.78–0.87 µM and SI > 380 with respect to the human dermal fibroblasts (HDF). In comparison, artemisone has an IC₅₀ of 0.26 µM, and a SI of 88 with the same cell lines. Overall, the N-glycosylated DHA-piperazine derivatives display antimalarial activities that are greatly superior to O-glycosides previously obtained from DHA.

Layer-by-layer nanocoating of antibacterial niosome on orthopedic implant

The major clinical hindrance of orthopedic implants is the bacterial infection, which can lead to biofilm formation and ultimately results in implant rejection. In this research, layer-by-layer nanocoating consists of vancomycin/PLA/vancomycin-loaded niosomes was designed. Vancomycin-loaded niosomes were formulated by thin film hydration method and the attributes of niosomes in terms of size, zeta potential, drug loading and EE, were assessed. The size was 340.5 ± 2.95 nm with the zeta potential and %EE was 45.4 ± 0.77 mV and 50.47 ± 3.66% respectively. The dip coating technique was used to deposit a thin film, which was characterized morphologically under FE-SEM. Drug release from coated bone plates with and without vancomycin-loaded niosomes was also studied and results suggested that bone plates coated with vancomycin-loaded niosomes have accumulated more vancomycin than the control group and hence aided in the prolonged release up to two weeks. These niosomes-coated bone plates demonstrated superior antibacterial activity for longer time period, without exhibiting any cytotoxic effects towards normal cells (L929). These findings offer a promising approach to control the bacterial colonization and biofilms formation. This thin film nano-coating can also be utilized in coating of other medical devices, which are prone to infections.

Topical Delivery of Withania somnifera Crude Extracts in Niosomes and Solid Lipid Nanoparticles

BACKGROUND

Withania somnifera is a medicinal plant native to India and is known to have anticancer properties. It has been investigated for its anti-melanoma properties, and since melanoma presents on the skin, it is prudent to probe the use of W. somnifera in topical formulations. To enhance topical drug delivery and to allow for controlled release, the use of niosomes and solid lipid nanoparticles (SLNs) as delivery vesicles were explored.

OBJECTIVE

The objective of this study is to determine the stability and topical delivery of W. somnifera crude extracts encapsulated in niosomes and SLNs.

MATERIALS AND METHODS

Water, ethanol, and 50% ethanol crude extracts of W. somnifera were prepared using 24 h soxhlet extraction which were each encapsulated in niosomes and SLNs. Franz cell diffusion studies were conducted with the encapsulated extracts to determine the release and skin penetration of the phytomolecules, withaferin A, and withanolide A.

RESULTS

The niosome and SLN formulations had average sizes ranging from 165.9 ± 9.4 to 304.6 ± 52.4 nm with the 50% ethanol extract formulations having the largest size. A small particle size seemed to have correlated with a low encapsulation efficiency (EE) of withaferin A, but a high EE of withanolide A. There was a significant difference (P < 0.05) between the amount of withaferin A and withanolide A that were released from each of the formulations, but only the SLN formulations managed to deliver withaferin A to the stratum corneum-epidermis and epidermis-dermis layers of the skin.

CONCLUSION

SLNs and niosomes were able to encapsulate crude extracts of W. somnifera and release the marker compounds, withaferin A, and withanolide A, for delivery to certain layers in the skin.

SUMMARY

Withania somnifera crude extracts were prepared using ethanol, water, and 50% ethanol as solvents. These three extracts were then incorporated into niosomes and solid lipid nanoparticles (SLNs) for use in skin diffusion studies, thus resulting in six formulations (ethanol niosome, water niosome, 50% ethanol niosome, ethanol SLN, water SLN, and 50% ethanol SLN). The diffusion of two marker compounds (withaferin A and withanolide A) from the formulations into the skin was then determined. Abbreviations used: API: Active pharmaceutical ingredient, ANOVA: Analysis of variance, ED: Epidermis-dermis, HPLC: High-performance liquid chromatography, HLB: Hydrophilic-lipophilic balance, NMR: Nuclear magnetic resonance spectroscopy, PDI: Polydispersity index, SLN: Solid lipid nanoparticle, SD: Standard deviation, SCE: Stratum corneum-epidermis, TEM: Transmission electron microscopy.

Topical and cutaneous delivery using nanosystems

The goal of topical and cutaneous delivery is to deliver therapeutic and other substances to a desired target site in the skin at appropriate doses to achieve a safe and efficacious outcome. Normally, however, when the stratum corneum is intact and the skin barrier is uncompromised, this is limited to molecules that are relatively lipophilic, small and uncharged, thereby excluding many potentially useful therapeutic peptides, proteins, vaccines, gene fragments or drug-carrying particles. In this review we will describe how nanosystems are being increasingly exploited for topical and cutaneous delivery, particularly for these previously difficult substances. This is also being driven by the development of novel technologies, which include minimally invasive delivery systems and more precise fabrication techniques. While there is a vast array of nanosystems under development and many undergoing advanced clinical trials, relatively few have achieved full translation to clinical practice. This slow uptake may be due, in part, to the need for a rigorous demonstration of safety in these new nanotechnologies. Some of the safety aspects associated with nanosystems will be considered in this review.

In vitro skin permeation of sinigrin from its phytosome complex

OBJECTIVES

Sinigrin is a major glucosinolate present in plants of the Brassicaceae family. Recently, sinigrin and its phytosome formulations have been investigated for its wound-healing actions, by our research group. The aim of this study was to demonstrate sinigrin drug release from its phytosome complex and also to determine whether the phytosome complex enhances the delivery of sinigrin into the skin when compared to free sinigrin.

METHODS

In vitro Franz cell diffusion studies were performed on human abdominal skin. The morphology of the phytosome complex was examined by transmission electron microscopy. The in vitro drug release was determined using dialysis sacks.

KEY FINDINGS

The in vitro drug release indicated a controlled and sustained release of sinigrin from the phytosome complex. Tape stripping results showed that the sinigrin-phytosome complex (0.5155 μg/ml) statistically significantly enhanced the delivery of sinigrin into the stratum corneum-epidermis when compared to the free sinigrin (0.0730 μg/ml).

CONCLUSIONS

These results suggested the possibility of utilizing sinigrin-phytosome complex, to optimally deliver sinigrin to the skin which can be further used for various skin-related diseases including wound healing.