A comprehensive review on transethosomes as a novel vesicular approach for drug delivery through transdermal route

Drug delivery through transdermal route is one of the effective methods for the application of drugs. It overcomes many drawbacks which are encountered with the oral route. Moreover, many drugs are not able to pass through the stratum corneum, which is the main barrier for the transdermal drug delivery. Formation of ultra-deformable vesicles (UDVs) is a novel technique for the transdermal applications of the drugs. Transethosomes (TEs), ethosomes, and transferosomes are all part of the UDV. Because of the presence of increased concentrations of ethanol, phospholipids, and edge activators, TEs provide improved drug permeation through the stratum corneum. Because of the elasticity of TEs, drug penetration into the deeper layer of skin also increases. TEs can be prepared using a variety of techniques, including the cold method, hot method, thin film hydration method, and the ethanol injection method. It increases patient adherence and compliance because it is a non-invasive procedure of administering drugs. Characterization of the TEs includes pH determination, size and shape, zeta potential, particle size determination, transition temperature, drug content, vesicle stability, and skin permeation studies. These vesicular systems can be utilized to deliver a variety of medications transdermally, including analgesics, antibiotics, antivirals, and anticancer and arthritis medications. This review aims to describe vesicular approaches that had been used to overcome the barrier for the transdermal delivery of drug and also describes brief composition, method of preparation, characterization tests, mechanism of penetration of TEs, as well as highlighted various applications of TEs in medicine.

Implementing Spanlastics for Improving the Ocular Delivery of Clotrimazole: In vitro Characterization, Ex vivo Permeability, Microbiological Assessment and In vivo Safety Study

Purpose

The aim of this study was to encapsulate clotrimazole (CLT), an antifungal drug with poor water solubility characteristics, into spanlastics (SPs) to provide a controlled ocular delivery of the drug.

Methods

Span 60 was used in the formulation of SPs with Tween 80, Pluronic F127, or Kolliphor RH40 as an edge activator (EA). The presence of EA offers more elasticity to the membrane of the vesicles which is expected to increase the corneal permeation of CLT. SPs were prepared using ethanol injection method applying 3² complete factorial design to study the effect of formulation variables (ratio of Span 60: EA (w/w) and type of EA) on SPs characteristics (encapsulation efficiency percent (EE%), average vesicle size (VS), polydispersity index (PDI) and zeta potential (ZP)). Design-Expert software was used to determine the optimum formulation for further investigations.

Results

The optimum formulation determined was S1, which contains 20 mg of Tween 80 used as an EA and 80 mg of Span 60. S1 exhibited EE% = 66.54 ± 7.57%, VS = 206.20 ± 4.95 nm, PDI = 0.39 ± 0.00 and ZP = −29.60 ± 0.99 mV. S1 showed highly elastic sphere-shaped vesicles. Furthermore, S1 displayed a sustained release profile and a higher ex vivo permeation across rabbit cornea relative to CLT suspension. Also, S1 revealed superior inhibition of Candida albicans development compared to CLT suspension applying 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction technique. Moreover, in vivo histopathological examination assured the safety of S1 after ophthalmic application in mature male albino rabbits.

Conclusion

Overall, the outcomes revealed the marked efficacy of SPs for ocular delivery of CLT.

Identifying Underlying Issues Related to the Inactive Excipients of Transfersomes based Drug Delivery System

Transfersomes are bilayer vesicles composed of phospholipid and edge activators, which are mostly surfactant. Transfersomes based drug delivery system has gained a lot of interest of the pharmaceutical researchers for their ability to improve drug penetration and permeation through the skin. Transdermal drug delivery via transfersomes has the potential to overcome the challenge of low systemic availability. However, this complex vesicular system has different issues to consider for developing a successful transdermal delivery system. One of the major ingredients, phospholipid, has versatile sources and variable effect on the vesicle size and drug entrapment in transfersomes. The other one, termed as edge activators or surfactant, has some crucial consideration of skin damage and toxicity depending upon its type and concentration. A complex interaction between type and concentration of phospholipid and surfactant was observed, which affect the physicochemical properties of transfersomes. This review focuses on the practical factors related to these two major ingredients, such as phospholipid and surfactant. The origin, purity, desired concentration, the susceptibility of degradation, etc. are the important factors for selecting phospholipid. Regarding surfactants, the major aspects are type and desired concentration. A successful development of transfersomes based drug delivery system depends on the proper considerations of these factors and practical aspects.

Fabrication of Highly Deformable Bilosomes for Enhancing the Topical Delivery of Terconazole: In Vitro Characterization, Microbiological Evaluation, and In Vivo Skin Deposition Study

The current study aimed to load terconazole (TCZ), an antifungal agent with low permeability characteristics, into highly deformable bilosomes (HBs) for augmenting its topical delivery. HBs contain edge activator in addition to the constituents of traditional bilosomes (Span 60, cholesterol, and bile salts). More elasticity is provided to the membrane of vesicles by the existence of edge activator and is expected to increase the topical permeation of TCZ. HBs were formulated using ethanol injection technique based on 2⁴ complete factorial design to inspect the impact of various formulation variables (bile salt type and amount, edge activator type, and sonication time) on HBs characteristics (entrapment efficiency percent (EE%), particle size (PS), polydispersity index (PDI), and zeta potential (ZP)). The optimum formula (HB14) was decided based on Design-Expert^® software and was utilized for further explorations. HB14 exhibited EE% = 84.25 ± 0.49%, PS = 400.10 ± 1.69 nm, PDI = 0.23 ± 0.01, and ZP = - 56.20 ± 0.00 mV. HB14 showed spherical vesicles with higher deformability index (9.94 ± 1.91 g) compared to traditional bilosomal formula (3.49 ± 0.49 g). Furthermore, HB14 showed superior inhibition of Candida albicans growth relative to TCZ suspension using XTT (2,3-bis(2-methyloxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) reduction assay. Moreover, in vivo skin deposition studies revealed superior TCZ deposition inside the skin from HB14 compared to traditional bilosomal formula and TCZ suspension. Moreover, histopathological examination in rats assured the safety of HB14 for topical use. Concisely, the obtained outcomes confirmed the pronounced efficacy of HBs for topical delivery of TCZ.

Development, Characterization and Use of Liposomes as Amphipathic Transporters of Bioactive Compounds for Melanoma Treatment and Reduction of Skin Inflammation: A Review

The skin is the largest organ in the human body, providing a barrier to the external environment. It is composed of three layers: epidermis, dermis and hypodermis. The most external epidermis is exposed to stress factors that may lead to skin conditions such as photo-aging and skin cancer. Some treatments for skin disease utilize the incorporation of drugs or bioactive compounds into nanocarriers known as liposomes. Liposomes are membranes whose sizes range from nano to micrometers and are composed mostly of phospholipids and cholesterol, forming similar structures to cell membranes. Thus, skin treatments with liposomes have lower toxicity in comparison to traditional treatment routes such as parenteral and oral. Furthermore, addition of edge activators to the liposomes decreases the rigidity of the bilayer structure making it deformable, thereby improving skin permeability. Liposomes are composed of an aqueous core and a lipidic bilayer, which confers their amphiphilic property. Thus, they can carry hydrophobic and hydrophilic compounds, even simultaneously. Current applications of these nanocarriers are mainly in the cosmetic and pharmaceutic industries. Nevertheless, new research has revealed promising results regarding the effectiveness of liposomes for transporting bioactive compounds through the skin. Liposomes have been well studied; however, additional research is needed on the efficacy of liposomes loaded with bioactive peptides for skin delivery. The objective of this review is to provide an up-to-date description of existing techniques for the development of liposomes and their use as transporters of bioactive compounds in skin conditions such as melanoma and skin inflammation. Furthermore, to gain an understanding of the behavior of liposomes during the process of skin delivery of bioactive compounds into skin cells.

Formulation of Sodium Valproate Nanospanlastics as a Promising Approach for Drug Repurposing in the Treatment of Androgenic Alopecia

Sodium valproate (SV) is an antiepileptic drug that is widely used in the treatment of different seizure disorders. The topical SV has a hair regenerative potential through activating the Wnt/β-catenin pathway and anagen phase induction. The aim of the current investigation was to fabricate nanospanlastics of SV for improving its dermal delivery by providing prolonged drug effect and increasing its permeability for treatment of androgenic alopecia (AGA). SV-loaded nanospanlastics were formulated according to 2³ factorial design by ethanol injection method using a non-ionic surfactant (Span 60) and edge activators (EAs), such as Tween 80 and Cremophor RH 40, to explore the influence of different independent variables on entrapment efficiency (EE%) and percentage drug released after 12 h (Q_12h) in order to choose the optimized formula using Design-Expert software. The optimized formula (F8) appeared as spherical deformable vesicles with EE% of 90.32 ± 2.18% and Q_12h of 90.27 ± 1.98%. F8 exhibited significant improvement of ex vivo permeation than free SV. The clinical study exhibited no comparable difference between F8 and marketed minoxidil lotion. However, F8 demonstrates less adverse effects than minoxidil lotion. Nanospanlastics could be a safe and effective method for improving the topical delivery of SV in the management of AGA.

Transfersomes: The Ultra-Deformable Carrier System for Non-Invasive Delivery of Drug

Vesicular systems have many advantages like prolonging the existence of the drug in the systemic circulation, minimizing the undesirable side-effects and helping the active moieties to reach their target sites using the carriers. However, the main drawback related to transdermal delivery is to cross stratum corneum, which can be overcome by the utilization of novel carrier systems e.g., transfersomes, which are ultra-deformable carrier systems composed of phospholipid (phosphatidylcholine) and edge activators (surfactants). Edge activators are responsible for the flexibility of the bilayer membranes of transfersomes. Different edge activators used in transfersomes include tween, span, bile salts (sodium cholate and sodium deoxycholate) and dipotassium glycyrrhizinate. These activators decrease the interfacial tension, thereby, increasing the deformability of the carrier system. Transfersomes can encapsulate both hydrophilic and hydrophobic drugs into a vesicular structure, which consists of one or more concentric bilayers. Due to the elastic nature of transfersomes, they can easily cross the natural physiological barriers i.e., skin and deliver the drug to its active site. The main benefit of using transfersomes as a carrier is the delivery of macromolecules through the skin by non-invasive route thereby increasing the patient's compliance. The transfersomal formulations can be used in the treatment of ocular diseases, alopecia, vulvovaginal candidiasis, osteoporosis, atopic dermatitis, tumor, leishmaniasis. It is also used in the delivery of growth hormones, anaesthesia, insulin, proteins, and herbal drugs. This review also focuses on the patents and clinical studies for various transfersomal products.

Nanogel loaded with surfactant based nanovesicles for enhanced ocular delivery of acetazolamide

Objective: Intraocular pressure has always been a great challenge for topical ophthalmic drugs. The study aimed to develop ocular surfactant based nanovesicles (NVs) carried in mucoadhesive nanogel providing efficient topical delivery of acetazolamide (ACZ). Methods: For the sake of optimizing formulation parameters, the effect of the type of edge activator and its ratio to sorbitan monostearate (Span 60) on the mean particle size, entrapment efficiency (%EE), and zeta potential (ZP) of produced NVs was investigated. Results: The selected formulation composed of Span 60:sodium deoxycholate with ratio 80:20 showed an average diameter of 202.90 nm, %EE of 90.2%, and ZP of -38.1 mV with a spherical and smooth surface. The ACZ loaded nanovesicles (ACZ-NVs) were embedded in different concentrations of Chitosan-sodium tripolyphosphate (CS-TPP) nanogels. The nanogel prepared using 1.5% CS showed the most promising viscosity, adhesion time, and rheological behavior (118,246 cP, 290 min, and thixotropic behavior, respectively). The in vitro release of ACZ showed a controlled release profile after incorporation in nanogels. The in vivo irritation test showed minimal irritation for the nanogel formulation compared to ACZ topical suspension. The effect of intraocular pressure lowering was significantly prolonged using ACZ-NV nanogels compared to ACZ oral tablets. Histopathological examination emphasized the healing power of CS on retinal atrophy. Conclusion: The research work indicated a promising potential for successful topical delivery of ACZ.

Preparation and Evaluation of Novel Transfersomes Combined with the Natural Antioxidant Resveratrol

Resveratrol (tran-3,5,4′-trihydroxystibene, RSV) is a kind of polyphenol which has anti-inflammatory, antioxidant, anti-allergy, and anti-cancer properties, as well as being a scavenger of free radicals and preventing cardiovascular diseases. However, it is quite unstable in light, heat, and other conditions, and decays easily due to environmental factors. For these reasons, this study used a new type of carrier, transfersome, to encapsulate RSV. Transfersome consists of phosphatidyl choline (PC) from a liposomal system and non-ionic edge activators (EA). EA are an important ingredient in the formulation of transfersome; they can enhance the flexibility of the lipid bimolecular membrane of transfersome. Due to its ultradeformability, it also allows drugs to penetrate the skin, even through the stratum corneum. We hope that this new encapsulation technique will improve the stability and enhance the permeability of RSV. Concluding all the tested parameters, the best production condition was 5% PC/EA (3:1) and 5% ethanol in distilled water, with an ultrasonic bath and stirring at 500 rpm, followed by high pressure homogenization. The optimal particle size was 40.13 ± 0.51 nm and the entrapment efficiency (EE) was 59.93 ± 0.99%. The results of antioxidant activity analysis showed that transfersomes were comparable to the RSV group (unencapsulated). During in vitro transdermal delivery analysis, after 6 h, D1-20(W) increased 27.59% by accumulation. Cell viability assay showed that the cytotoxicity of D3-80(W) was reduced by 34.45% compared with the same concentration of RSV. Therefore, we successfully prepared RSV transfersomes and also improved the stability, solubility, and safety of RSV.

Fabrication of novel elastosomes for boosting the transdermal delivery of diacerein: statistical optimization, ex-vivo permeation, in-vivo skin deposition and pharmacokinetic assessment compared to oral formulation

Diacerein (DCN) is a hydrophobic osteoarthritis (OA) drug with short half-life and low oral bioavailability. Furthermore, DCN oral administration is associated with diarrhea which represents obstacle against its oral use. Hence, this article aimed at developing elastosomes (edge activator (EA)-based vesicular nanocarriers) as a novel transdermal system for delivering DCN efficiently and avoiding its oral problems. For achieving this goal, elastosomes were prepared according to 41.21 full factorial design using different EAs in varying amounts. The prepared formulae were characterized regarding their entrapment efficiency percentage (EE%), particle size (PS), polydispersity index (PDI), zeta potential (ZP) and deformability index (DI). Desirability function was employed using Design-Expert® software to select the optimal elastosomes (E1) which showed EE% of 96.25 ± 2.19%, PS of 506.35 ± 44.61 nm, PDI of 0.46 ± 0.09, ZP of -38.65 ± 0.91 mV, and DI of 12.74 ± 2.63 g. In addition, E1 was compared to DCN-loaded bilosomes and both vesicles exhibited superior skin permeation potential and retention capacity compared to drug suspension. In-vivo histopathological study was performed which ensured the safety of E1 for topical application. Furthermore, the pharmacokinetic study conducted in albino rabbits demonstrated that there was no significant difference in the rate and extent of DCN absorption from topically applied E1 compared to oral suspension. Multiple level C in-vitro in-vivo correlation showed good correlation between in-vitro release and in-vivo drug performance for E1 and DCN oral suspension. Overall, results confirmed the admirable potential of E1 to be utilized as novel carrier for transdermal delivery of DCN and bypassing its oral side effects.