Vesicles as a tool for transdermal and dermal delivery

Simple amides of oleanolic acid as effective penetration enhancers

Transdermal transport is now becoming one of the most convenient and safe pathways for drug delivery. In some cases it is necessary to use skin penetration enhancers in order to allow for the transdermal transport of drugs that are otherwise insufficiently skin-permeable. A series of oleanolic acid amides as potential transdermal penetration enhancers was formed by multistep synthesis and the synthesis of all newly prepared compounds is presented. The synthetized amides of oleanolic acid were tested for their in vitro penetration promoter activity. The above activity was evaluated by means of using the Fürst method. The relationships between the chemical structure of the studied compounds and penetration activity are presented.

Skin targeted lipid vesicles as novel nano-carrier of ketoconazole: characterization, in vitro and in vivo evaluation

Liposomal carriers for topical drug delivery have been studied since the 1980s and have evoked a considerable interest. However, the conventional liposomes do not deeply penetrate into the skin and remain confined to the outer layer of SC. In order to increase skin targeting of ketoconazole (KCZ), a hydrophobic broad-spectrum antifungal agent, this study describes novel lipid vesicles as nano-carriers for topical delivery. In this paper, lipid vesicular systems including conventional liposomes (CL), ethosomes, deformable liposomes (DL) and ethanol-containing deformable liposomes (DEL) were prepared as nano-carriers for KCZ, respectively. Sodium dodecyl sulfate [SDS, 0.08 % (W/V)] was used as edge activator for DL and DEL preparation. Characterization of the vesicles was based on particle size, zeta potential, entrapment efficiency and transmission electron microscopy (TEM). In addition, in vitro permeation profile was obtained using vertical diffusion Franz cells by porcine skin. The in vivo accumulation of KCZ was also evaluated in rat skin. Confocal microscopy was performed to visualize the penetration of fluorescently labeled vesicles into skin. All of the lipid vesicles showed almost spherical structures with low polydispersity index (PDI < 0.3) and nano-metric size (no more than 160 nm). The results demonstrated that DEL dramatically improved both in vitro and in vivo skin deposition compared to the CLs (P < 0.05), which was further confirmed by confocal laser scanning microscopy study. In vivo pharmacodynamic studies showed DEL improved antifungal activity against Candida albicans in shorter duration of time. Therefore, based on present study, the novel nano-carrier DEL capable of enhancing skin target effect and forming a micro drug-depot could serve as an effective skin targeting delivery for KCZ as an anti-fungal agent in local therapy.

Investigating the potential of employing bilosomes as a novel vesicular carrier for transdermal delivery of tenoxicam

Bilosomes represent an evolving vesicular carrier that have been explored for oral vaccines delivery based on its ability to resist enzymes and bile salts in the gastrointestinal tract (GIT). Bilosomes vesicles are formed of bilayer membrane of non-ionic surfactant molecules encompassing bile salts. Although, bilosomes have not been proposed for transdermal drug delivery, this carrier seems to have promising potential in this regard. Accordingly, the aim of this investigation was to assess the capability and safety of utilizing bilosomes for transdermal delivery of tenoxicam (TX) as a model drug. A 3(1)2(2) full factorial design was adopted to study the effects of different formulation parameters on bilosomes properties and select the optimal formulation using Design-Expert(®) software. The selected formulation displayed nano-sized spherical vesicles (242.5 ± 6.43nm) with reasonable entrapment efficiency percent (68.33 ± 2.33%). Confocal laser scanning microscopy confirmed the capability of the flourolabeled bilosomes to penetrate deep within the skin. Both, ex vivo permeation and in vivo skin deposition studies confirmed the superiority of bilosomes over drug solution in delivering TX transdermally. In addition, in vivo histopathological study proved the safety of topically applied bilosomes. In summary, the highlighted results confirmed that bilosomes can be further adopted for delivering drugs transdermally.

Formulation design for topical drug and nanoparticle treatment of skin disease

The skin has evolved to resist the penetration of foreign substances and particles. Topical therapeutic and cosmeceutical delivery is a growing field founded on selectively overcoming this barrier. Both the biology of the skin and the nature of the formulation/active ingredient must be aligned for efficient transcutaneous delivery. This review discusses the biological changes in the skin barrier that occur with common dermatological conditions. This context is the foundation for the discussion of formulation strategies to improve penetration profiles of common active ingredients in dermatology. Finally, we compare and contrast those approaches to recent advances described in the research literature with an eye toward the future of topical formulation design.

Cell penetrating peptide conjugated liposomes as transdermal delivery system of Polygonum aviculare L. extract

In this study, Polygonum aviculare L. extract, which has superior antioxidative and cellular membrane protective activity, was loaded onto cell penetrating peptide (CPP) conjugated liposomes to enhance transdermal delivery. The physical characteristics of typical liposomes and CPP-conjugated liposomes containing P. aviculare extract were evaluated. The particle sizes of both liposomes were approximately 150 nm. Whereas the zeta potential of typical liposomes was -45 mV, that of CPP-conjugated liposomes was +42 mV. The loading efficiency of P. aviculare extract in both liposomes was calculated to be about 83%. Fluorescent-labeled liposomes were prepared to evaluate cellular uptake and skin permeation efficiency. Using flow cytometry, we found that CPP-conjugated liposomes improved cellular uptake of the fluorescent dye as compared with the typical liposomes. In addition, the skin permeation of CPP-conjugated liposomes was proved higher than that of typical liposomes by confocal laser scanning microscopy studies and Franz diffusion cell experiments. The improved cellular uptake and skin permeation of the CPP-conjugated liposomes were due to the cationic arginine-rich peptide. In vivo studies also determined that the CPP-conjugated liposomes were more effective in depigmentation and anti-wrinkle studies than typical liposomes. These results indicate that the CPP-conjugated liposomes could be effective for transdermal drug delivery of antioxidant and anti-aging therapeutics.

Formulation and evaluation of a topical niosomal gel containing a combination of benzoyl peroxide and tretinoin for antiacne activity

A skin disease, like acne, is very common and normally happens to everyone at least once in their lifetime. The structure of the stratum corneum is often compared with a brick wall, with corneocytes surrounded by the mortar of the intercellular lipid lamellae. One of the best options for successful drug delivery to the affected area of skin is the use of elastic vesicles (niosomes) which can be transported through the skin through channel-like structures. In this study, a combination of tretinoin (keratolytic agent) and benzoyl peroxide (BPO) (a potent antibacterial) was given by using niosomes as promising carriers for the effective treatment of acne by acting on a pathogenic site. In this section, niosomal gel formulation encapsulated drugs have been evaluated for in vitro, ex vivo, and in vivo, for their predetermined characteristics; and finally the stability of the niosome gel was tested at different temperature conditions for understanding of the storage conditions required for maintaining the quality of formulation attributes. The prepared niosome was found to be in the range of 531 nm with a zeta potential of −43 mV; the entrapment efficiencies of tretinoin (TRA) and BPO niosomes were found to be 96.25%±0.56% and 98.75%±1.25%, respectively. The permeated amount of TRA and BPO from the niosomal gel after 24 hours was calculated as 6.25±0.14 μg/cm² and 5.04±0.014 μg/cm², respectively. A comparative drug retention study in Wistar rat skin using cream, an alcoholic solution, and a niosomal gel showed 11.54 μg, 2.68 μg, and 15.54 μg amounts of TRA and 68.85 μg, 59.98 μg, and 143.78 μg amounts of BPO were retained in the layers of skin, respectively. In vivo studies of the niosomal gel and antiacne cream of TRA and BPO showed that the niosomal gel was more efficacious than the antiacne cream because niosomal gels with a 4.16-fold lower dose of BPO provided the same therapeutic index at targeted sites in comparison to the antiacne cream.

Bile salts-containing vesicles: promising pharmaceutical carriers for oral delivery of poorly water-soluble drugs and peptide/protein-based therapeutics or vaccines

Most of the new drugs, biological therapeutics (proteins/peptides) and vaccines have poor performance after oral administration due to poor solubility or degradation in the gastrointestinal tract (GIT). Though, vesicular carriers exemplified by liposomes or niosomes can protect the entrapped agent to a certain extent from degradation. Nevertheless, the harsh GIT environment exemplified by low pH, presence of bile salts and enzymes limits their capabilities by destabilizing them. In response to that, more resistant bile salts-containing vesicles (BS-vesicles) were developed by inclusion of bile salts into lipid bilayers constructs. The effectiveness of orally administrated BS-vesicles in improving the performance of vesicles has been demonstrated in researches. Yet, these attempts did not gain considerable attention. This is the first review that provides a comprehensive overview of utilizing BS-vesicles as a promising pharmaceutical carrier with a special focus on their successful applications in oral delivery of therapeutic macromolecules and vaccines. Insights on the possible mechanisms by which BS-vesicles improve the oral bioavailability of the encapsulated drug or immunological response of entrapped vaccine are explained. In addition, methods adopted to prepare and characterize BS-vesicles are described. Finally, the gap in the scientific researches tackling BS-vesicles that needs to be addressed is highlighted.

Physical characterization and in vitro skin permeation of solid lipid nanoparticles for transdermal delivery of quercetin

OBJECTIVE

Quercetin, a phenolic compound isolated from plants, can act as an antioxidant to protect the skin from oxidative stress induced by ultraviolet rays. The aims of this work were (i) to compare the physical characterization of quercetin-loaded solid lipid nanoparticles (QSLNs) and (ii) to investigate the enhanced skin permeation of quercetin using QSLNs.

METHODS

QSLNs were prepared with a certain amount lipid (palmitic acid) and the different ratio of surfactant (Tween(®) 80) by homogenization and ultrasonification method.

RESULTS

QSLNs showed mono-dispersed particle size distribution in the ranges of 274.0-986.6 nm and zeta potential from -50.4 to -29.4 mV. Entrapment efficiency of QSLN was 15.2-46.2%, and their crystallinity index was low (0-18.2%). In vitro occlusion test showed QSLN-2 has the highest occlusive effect due to its smallest particle size (274.0 nm), and through these result, QSLN-2 was selected as the optimum formulation. Transmission electron microscopy (TEM) analysis further confirmed the uniform spherical shape of QSLN-2 particles. Field emission-scanning electron microscope (FE-SEM) analysis and histological observation of hairless rat skin showed that the lipid particles of QSLN-2 formed a fused lipid film and, subsequently, it hydrated the surface of the rat skin. Franz diffusion cell was used to measure in vitro skin permeation of quercetin dissolved in propylene glycol (QPG), QSLN-2 and QSLN-3. The results showed that QSLN-2 (33.5 μg cm(-2) , 21.9%) exhibited higher skin permeability than QPG (6.6 μg cm(-2) , 4.2%) and QSLN-3 (14.2 μg cm(-2) , 9.1%), which was visually confirmed by confocal laser scanning microscope (CLSM) image analysis as well.

CONCLUSION

The results suggest that QSLN-2, prepared with a surfactant content of 2%, could be used as useful skin delivery system for transdermal delivery of hydrophobic antioxidants such as quercetin.

Terpene-containing PEGylated liposomes as transdermal carriers of a hydrophilic compound

We investigated the effect of PEGylated liposomes (PLs) containing a terpene on the penetration of a hydrophilic compound through porcine skin. PLs composed of N-(carbonyl-methoxypolyethyleneglycol-2000)-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (PEG2000-DSPE), the sodium salt of PEG2000-DSPE, phosphatidylcholine (PC), cholesterol (Chol), Tween 20, and d-limonene were prepared as carriers for fluorescein sodium (NaFI). The physicochemical characteristics of PLs and their effects on in vitro skin penetration were evaluated. Tape stripping was used to evaluate NaFI deposition in skin layers, and confocal laser scanning microscopy (CLSM) was used to investigate the depth of skin penetration and the pathways used by NaFI-loaded vesicles. PLs containing d-limonene were smaller and conferred higher entrapment efficiency and skin penetration on NaFI than did PLs and conventional liposomes (CLs). The deposition of NaFI from PLs with d-limonene was greater in epidermis and dermis (6.10±1.74 µg) than stratum corneum (2.06±0.47 µg). CLSM images revealed that NaFI penetrated into the deepest skin layer with maximum fluorescence intensity. NaFI penetrated deeper (180 µm) in follicular than nonfollicular regions (145 µm), suggesting a transfollicular pathway predominates in skin penetration by NaFI-loaded PLs. In conclusion, grafting PEG onto ultra-deformable liposomes may enhance transdermal NaFI delivery and may be used as a carrier to prolong liposome circulation time.

Effective topical delivery systems for corticosteroids: dermatological and histological evaluations

Atopic dermatitis (AD) is a chronic and relapsing skin disease with severe eczematous lesions. Long-term topical corticosteroid treatment can induce skin atrophy, hypopigmentation and transepidermal water loss (TEWL) increase. A new treatment approach was needed to reduce the risk by dermal targeting. For this purpose, Betamethasone valerate (BMV)/Diflucortolone valerate (DFV)-loaded liposomes (220-350 nm) were prepared and incorporated into chitosan gel to obtain adequate viscosity (∼13 000 cps). Drugs were localized in stratum corneum + epidermis of rat skin in ex-vivo permeation studies. The toxicity was assessed on human fibroblast cells. In point of in-vivo studies, pharmacodynamic responses, treatment efficacy and skin irritation were evaluated and compared with previously prepared nanoparticles. Liposome/nanoparticle in gel formulations produced higher paw edema inhibition in rats with respect to the commercial cream. Similar skin blanching effect with commercial creams was obtained via liposome in gels although they contain 10 times less drug. Dermatological scoring results, prognostic histological parameters and suppression of mast cell numbers showed higher treatment efficiency of liposome/nanoparticle in gel formulations in AD-induced rats. TEWL and erythema measurements confirmed these results. Overview of obtained results showed that liposomes might be an effective and safe carrier for corticosteroids in skin disease treatment.

Experimental design and optimization of raloxifene hydrochloride loaded nanotransfersomes for transdermal application

Raloxifene hydrochloride, a highly effective drug for the treatment of invasive breast cancer and osteoporosis in post-menopausal women, shows poor oral bioavailability of 2%. The aim of this study was to develop, statistically optimize, and characterize raloxifene hydrochloride-loaded transfersomes for transdermal delivery, in order to overcome the poor bioavailability issue with the drug. A response surface methodology experimental design was applied for the optimization of transfersomes, using Box-Behnken experimental design. Phospholipon^® 90G, sodium deoxycholate, and sonication time, each at three levels, were selected as independent variables, while entrapment efficiency, vesicle size, and transdermal flux were identified as dependent variables. The formulation was characterized by surface morphology and shape, particle size, and zeta potential. Ex vivo transdermal flux was determined using a Hanson diffusion cell assembly, with rat skin as a barrier medium. Transfersomes from the optimized formulation were found to have spherical, unilamellar structures, with a homogeneous distribution and low polydispersity index (0.08). They had a particle size of 134±9 nM, with an entrapment efficiency of 91.00%±4.90%, and transdermal flux of 6.5±1.1 μg/cm²/hour. Raloxifene hydrochloride-loaded transfersomes proved significantly superior in terms of amount of drug permeated and deposited in the skin, with enhancement ratios of 6.25±1.50 and 9.25±2.40, respectively, when compared with drug-loaded conventional liposomes, and an ethanolic phosphate buffer saline. Differential scanning calorimetry study revealed a greater change in skin structure, compared with a control sample, during the ex vivo drug diffusion study. Further, confocal laser scanning microscopy proved an enhanced permeation of coumarin-6-loaded transfersomes, to a depth of approximately160 μM, as compared with rigid liposomes. These ex vivo findings proved that a raloxifene hydrochloride-loaded transfersome formulation could be a superior alternative to oral delivery of the drug.

Nanovesicles for transdermal delivery of felodipine: Development, characterization, and pharmacokinetics

Aim:

The research traces development of nanovesicles to attain enhanced transdermal delivery of felodipine and also investigates parameters for optimization of variable membrane compositions containing soya- and egg lecithin and edge activator.

Materials and Methods:

Rotary evaporation sonication method was employed to obtain tranfersomal formulation that was characterized for vesicle shape and size, polydispersity index (PDI), zeta potential, entrapment and loading efficiency, deformability index and in vitro skin permeation.

Results:

Spherical nanovesicles of 75.71 ± 5.4 nm with PDI 0.228 and zeta potential of −49.8 were adjudged as the best formulation (MF8). MF8 displayed maximum entrapment and loading efficiency with a high deformability index of 119.68. In vitro permeation across rat skin by MF8 reported 256% enhancement in permeation (flux = 23.72 ± 0.64) when compared with transdermal control formulation and followed zero order kinetics (Case-II). Pharmacokinetic studies revealed that transdermal administration, in contrast to oral delivery provided relatively constant, sustained blood concentration with minimal plasma fluctuation, rapid and prolonged peak time. The relative bioavailability of felodipine was found 358.42% versus oral administration that was well supported by the outcomes of confocal laser scanning microscopic studies that suggested rapid permeation of drugs to across dermal layers.

Conclusion:

The results conclude that composition variation and method of preparation elicited significant effect on the vesicle characteristic and proved the transcendency of felodipine loaded transfersomes.

Investigation of the mechanism of enhanced skin penetration by ultradeformable liposomes

This study aimed to determine the mechanism by which ultradeformable liposomes (ULs) with terpenes enhance skin penetration for transdermal drug delivery of fluorescein sodium, using transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). Skin treated with ULs containing d-limonene, obtained from in vitro skin penetration studies, was examined via TEM to investigate the effect of ULs on ultrastructural changes of the skin, and to evaluate the mechanism by which ULs enhance skin penetration. The receiver medium collected was analyzed by TEM and CLSM to evaluate the mechanism of the drug carrier system. Our findings revealed that ULs could enhance penetration by denaturing intracellular keratin, degrading corneodesmosomes, and disrupting the intercellular lipid arrangement in the stratum corneum. As inferred from the presence of intact vesicles in the receiver medium, ULs are also able to act as a drug carrier system. CLSM images showed that intact vesicles of ULs might penetrate the skin via a transappendageal pathway, potentially a major route of skin penetration.

Challenges associated with Penetration of Nanoparticles across Cell and Tissue Barriers: A Review of Current Status and Future Prospects

Nanoparticles (NPs) have emerged as an effective modality for the treatment of various diseases including cancer, cardiovascular and inflammatory diseases. Various forms of NPs including liposomes, polymer particles, micelles, dendrimers, quantum dots, gold NPs and carbon nanotubes have been synthesized and tested for therapeutic applications. One of the greatest challenges that limit the success of NPs is their ability to reach the therapeutic site at necessary doses while minimizing accumulation at undesired sites. The biodistribution of NPs is determined by body's biological barriers that manifest in several distinct ways. For intravascular delivery of NPs, the barrier manifests in the form of: (i) immune clearance in the liver and spleen, (ii) permeation across the endothelium into target tissues, (iii) penetration through the tissue interstitium, (iv) endocytosis in target cells, (v) diffusion through cytoplasm and (vi) eventually entry into the nucleus, if required. Certain applications of NPs also rely on delivery through alternate routes including skin and mucosal membranes of the nose, lungs, intestine and vagina. In these cases, the diffusive resistance of these tissues poses a significant barrier to delivery. This review focuses on the current understanding of penetration of NPs through biological barriers. Emphasis is placed on transport barriers and not immunological barriers. The review also discusses design strategies for overcoming the barrier properties.

Liposomes for (trans)dermal drug delivery: the skin-PVPA as a novel in vitro stratum corneum model in formulation development

Penetration potential of vesicles destined for trans(dermal) administration remains to be of great interests both in respect to drug therapy and cosmetic treatment. This study investigated the applicability of the phospholipid vesicle-based permeation assay (PVPA) as a novel in vitro skin barrier model for screening purposes in preformulation studies. Various classes of liposomes containing hydrophilic model drug were examined, including conventional liposomes (CLs), deformable liposomes (DLs) and propylene glycol liposomes (PGLs). The size, surface charge, membrane deformability and entrapment efficiency were found to be affected by the vesicle lipid concentration, the presence of the surfactant and propylene glycol. All liposomes exhibited prolonged drug release profiles with an initial burst effect followed by a slower release phase. The permeation of the drug from all of the tested liposomes, as assessed with the mimicked stratum corneum--PVPA model, was significantly enhanced as compared to the permeability of the drug in solution form. Although the DLs and the PGLs exhibited almost the same membrane elasticity, the permeability of the drug delivered by PGLs was higher (6.2 × 10⁻⁶ cm/s) than DLs (5.5 × 10⁻⁶ cm/s). Therefore, this study confirmed both the potential of liposomes as vesicles in trans(dermal) delivery and potential of the newly developed skin-PVPA for the screening and optimization of liposomes at the early preformulation stage.

Force measurements on natural membrane nanovesicles reveal a composition-independent, high Young's modulus

Mechanical properties of nano-sized vesicles made up of natural membranes are crucial to the development of stable, biocompatible nanocontainers with enhanced functional, recognition and sensing capabilities. Here we measure and compare the mechanical properties of plasma and inner membrane nanovesicles ∼80 nm in diameter obtained from disrupted yeast Saccharomyces cerevisiae cells. We provide evidence of a highly deformable behaviour for these vesicles, able to support repeated wall-to-wall compressions without irreversible deformations, accompanied by a noticeably high Young's modulus (∼300 MPa) compared to that obtained for reconstituted artificial liposomes of similar size and approaching that of some virus particles. Surprisingly enough, the results are approximately similar for plasma and inner membrane nanovesicles, in spite of their different lipid compositions, especially on what concerns the ergosterol content. These results point towards an important structural role of membrane proteins in the mechanical response of natural membrane vesicles and open the perspective to their potential use as robust nanocontainers for bioapplications.

Formulation and evaluation of guggul lipid nanovesicles for transdermal delivery of aceclofenac

Context. Most new drugs have low water solubility and liposome is an important formulation to administer such drugs; however, it is quite unstable and has negligible systemic absorption. Objective. Aceclofenac nanovesicles were made using guggul lipid for formulating stable transdermal formulation. Materials and Methods. Guggul lipid was formulated into vesicles along with cholesterol and dicetyl phosphate using film hydration method. The formulations were analyzed for physicochemical properties and stability. Then its skin permeation and anti-inflammatory activity were determined. Results. Both categories of vesicles (PC and GL) showed optimum physicochemical properties; however, accelerated stability study showed considerable differences. GL-1 was appreciably stable for over 6 months at 4°C. Corresponding gels (PCG-1 and GLG-1) showed C_max values at 4.98 and 7.32 μg/mL along with the T_max values at 4 and 8 hours, respectively. GLG-1 inhibited edema production by 90.81% in 6 hours. Discussion. PC liposomes are unstable at higher temperature and upon longer storage. The formulation with higher lipid content (GL-1) showed good drug retention after 24 hours and appreciable stability both at higher temperature and for longer duration. Guggul lipid being a planar molecule might be stacked in vesicle wall with cholesterol. Conclusion. The composition of the nanovesicle played an important role in stability and drug permeation. Guggul lipid is suitable for producing stable vesicles.

Miconazole nitrate bearing ultraflexible liposomes for the treatment of fungal infection

Miconazole nitrate is a widely used antifungal agent, but its use in topical formulations is not efficacious because deep seated fungal infections are difficult to treat with conventional topical formulation. Miconazole nitrate loaded ultraflexible liposomes have been prepared and their topical performance has been compared with conventional liposomes containing miconazole nitrate. Various ultraflexible liposomal formulations were prepared and extensively characterized for vesicular shape, size, entrapment efficiency, degree of deformability and in-vitro skin permeation through rat skin. Higher rate of drug transfer across the skin with ultraflexible liposomal formulations of miconazole nitrate suggests that the drug in its lipo-solubilized state might have gained facilitated entry into the tough barrier consisting of subcutaneous. In-vivo study showed better antifungal activity as compared to traditional liposomes and plain drug solution. This was confirmed through fluoroscence microscopy. It is concluded that prepared ultraflexible liposomes can facilitate improved and localized drug action in the skin, thus providing a better option to deal with deep seated skin problems.

Development of novel topical drug delivery system containing cisplatin and imiquimod for dual therapy in cutaneous epithelial malignancy

CONTEXT

Strategy of dual therapy has been proposed to minimize the amount of each drug and to achieve the synergistic effect for cancer therapies.

OBJECTIVE

The aim of this study was to develop an effective drug delivery system for the simultaneous topical delivery of two anti-tumor agents, cisplatin and imiquimod.

MATERIAL AND METHODS

The preformulation studies were carried out in terms of tests for identification, solubility profile, determination of partition coefficient and simultaneous estimation of both drugs by UV-Visible spectrophotometer and High Performance Liquid Chromatography (HPLC). Drug-drug and drug-excipients interactions were examined by thin layer chromatography, infrared spectroscopy, differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Provesicular drug delivery system (protransfersome gel formulation) have been prepared and characterized by in vitro and in vivo parameters.

RESULTS

The mean size, poly dispersity index (PDI) and zeta potential of transfersomal vesicles formed by protransfersome hydration were 429.5 nm, 0.631 and -68.1 Mv, respectively. The prepared formulation showed toxicity on cutaneous squamous cell carcinoma cell line (A-431) at 200 µg (cisplatin) and 1 mg (imiquimod) concentration of drug in combination against control. The cisplatin- and imiquimod-loaded provesicular dual-drug delivery system achieved an optimal antitumor effect, increase in lifespan, antiviral, and toxicity reduction, revealing the advantage of site specific drug delivery and the modified combination therapy.

DISCUSSION

Cisplatin delivery through protransfersome gel in combination with imiquimod may potentiate the activity against solid tumors of epidermal origin.

CONCLUSION

Data revealed that combination therapy considerably enhances antitumor efficacy of the drug for skin-cited malignancies.

Molecular structural transformation regulated dynamic disordering of supramolecular vesicles as pH-responsive drug release systems

The spontaneous release of drug payloads in the whole body always results in the compromised drug bioavailability and ultimate therapeutic efficacy. To achieve enhanced therapeutic efficacy and reduced side effects, pH-responsive targeted drug delivery systems have been studied due to their enhanced tumor accumulation and controllable maximum drug release feature. The present study described a co-assembly constructed by a pH responsive molecule (i.e., malachite green carbinol base (MG)) and liposome for highly efficient doxorubicin (DOX) release in tumor cells (MG-DOX⊂L). The structural transformation of MG effectively regulates the drug release profile in acidic environment. The pH-responsive sensitivity of co-assembly can be fine-tuned by altering the mixing ratios of building blocks with pH responders (i.e., MG molecules). MG-DOX⊂L was beneficial for the DOX release at pH5.0 and showed a higher cytotoxicity in KB cells owing to the pH-responsive drug release in acidic organelles following endocytosis pathway. In vivo tumor targetability and growth inhibition were evaluated in KB cell-xenografted nude mice. We have demonstrated that effective tumor growth inhibition in vivo is attributed to the synergistic contributions from highly efficient cellular entry and responsive intracellular release of DOX from MG-DOX⊂L.

An experimental model of contact dermatitis: evaluation of the oxidative profile of Wistar rats treated with free and nanoencapsulated clobetasol

OBJECTIVE

An experimental animal model of contact dermatitis (CD) was used to investigate the effects of free and nanoencapsulated clobetasol propionate on the skin and on the oxidative profile of liver tissue.

METHODS

Female Wistar rats were divided into six groups, each containing eight rats. The first group, control (C), was sensitized with solid vaseline. Group 2, (CD), was sensitized with 5% NiSO(4). Groups 3 and 4 were sensitized with 5% NiSO(4) and treated with free (FC) and nanoencapsulated (NC) clobetasol (0.42 mg/g), respectively, daily for 5 days. Group 5 was treated with nanoencapsulated clobetasol (0.42 mg/g) on days 1, 3, and 5 (C135) and group 6 received a hydrogel containing empty nanoparticles (NP) daily for 5 days. Thiobarbituric acid reactive substances (TBARS), carbonyl levels, non-protein sulfhydryl groups (NPSH) and catalase activity were measured in liver homogenates.

RESULTS

A significant increase was observed in the levels of TBARS, NPSH, and catalase activity for the groups CD and NP.

DISCUSSION

Our results suggest that both NiSO(4) sensitization and NP administration induced oxidation of cellular lipids and activated the antioxidant enzyme catalase to protect from this damage. These results also indicated that daily treatment with the free and nanoencapsulated clobetasol, as well as treatment with the nanoencapsulated clobetasol every other day, were able to prevent these redox alterations and protect against histological damage.

Construction of hyaluronic acid noisome as functional transdermal nanocarrier for tumor therapy

To develop a functional nanosized transdermal drug delivery system for tumor therapy, amphiphilic hyaluronic acid (HA) based niosome was constructed combining transdermal and tumor targeting ability in one entity. HA esterified with monostearin, the conjugate labeled as HA-GMS self-assembled onto niosome surface and formed HA-niosome. The multilayer vesicle had small size (around 40 nm), good stability and desirable drug encapsulating efficacy, and well compatible with blood. It exhibited better endocytosis to mouse breast tumor cell (4T1) than the control chitosan nanoparticle, which was verified qualitatively and quantitatively. Skin permeation of HA-niosome was proven to be efficient using in vitro stratum corneum model and in vivo fluorescence observation. Histological section study confirmed the security and efficiency of transdermal permeation. The results evidence HA-niosome to be exciting and promising for tumor therapy through trandermal administration.

Performance of transdermal therapeutic systems: Effects of biological factors

Transdermal drug delivery (TDD) is a technique that is used to deliver a drug into the systemic circulation across the skin. This mechanism of drug delivery route has many advantages, including steady drug plasma concentrations, improved patient compliance, elimination of hepatic first pass, and degradation in the gastrointestinal tract. Over the last 30 years, many transdermal products have been launched in the market. Despite the inherent advantages of TDD and the growing list of transdermal products, one of the major drawbacks to TDD is the occurrence of inter- and intraindividual variation in the absorption of the drug across the skin. A majority of these variations are caused by biological factors, such as gender, age, ethnicity, and skin hydration and metabolism. These factors affect the integrity and the barrier qualities of the skin, which subsequently result in the variation in the amount of drug absorbed. The main objective of this review article is to provide a concise commentary on the biological factors that contribute to the variation in transdermal permeation of drugs across human skin and the available transdermal therapeutic systems that may reduce the variations caused by biological factors.

Ultra-adaptable nanovesicular systems: a carrier for systemic delivery of therapeutic agents

The skin acts as a barrier and prevents transcutaneous delivery of therapeutic agents. Transferosomes are novel vesicular systems that are several times more elastic than other vesicular systems. These are composed of phospholipids, edge activator and ethanol and are applied in a non-occlusive manner. Owing to their ultradeformability, they have the potential to deliver therapeutic agents across the intact skin in a non-invasive and non-allergenic manner. The present review attempts to provide an in-depth account of ultra-adaptable nanovesicular systems. The current investigation, besides compiling existing knowledge in a systematic manner, also includes information like regulatory aspects of excipients used in preparation, summary of clinical investigations performed, marketed preparations available, research reports and patent reports related to transfersomes.

Ultradeformable liposomes with terpenes for delivery of hydrophilic compound

Ultradeformable liposomes containing penetration enhancers were created to deliver NaFl. Vesicles were investigated for their particle size, zeta potential, NaFl entrapment efficiency (%EE), loading efficiency, and in vitro skin penetration. The vesicles obtained were spherical in shape, with a particle size of less than 100 nm and a negative surface charge (-6 to -11 mV). The %EE of NaFl loaded in vesicles ranged from 37 to 48%. Ultradeformable liposomes with monoterpenes (d-limonene, 1,8-cineole and geraniol) significantly improved NaFl penetration through the skin. Confocal laser scanning microscopy analysis confirmed skin-penetration results and was used to evaluate the behavior of hydrophilic compounds penetrating through the skin.

Influence of the flexible liposomes on the skin deposition of a hydrophilic model drug, carboxyfluorescein: dependency on their composition

This study focuses on the effect of different flexible liposomes containing sodium cholate, Tween 80, or cineol on skin deposition of carboxyfluorescein (CF). Size distribution, morphology, zeta potential, and stability of the prepared vesicles were evaluated. The influence of these systems on the skin deposition of CF utilizing rat skin as membrane model was investigated. Results showed that all of the investigated liposomes had almost spherical shapes with low polydispersity (PDI < 0.3) and particles size range from 83 to 175 nm. All liposomal formulations exhibited negative zeta potential, good drug entrapment efficiency, and stability. In vitro skin deposition data showed that flexible liposomes gave significant deposition of CF on the skin compared to conventional liposomes and drug solutions. This study revealed that flexible liposomes, containing cineole, were able to deliver higher amount of CF suggesting that the hydrophilic drugs delivery to the skin was strictly correlated to the vesicle composition.