Liposomes as a topical delivery system: the role of size on transport studied by the EPR imaging method (original) (raw)
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Novel vesicular carriers for topical drug delivery and their applications
International Journal of Pharmaceutical Sciences Review and Research
Delivery of drug through topical route represents a most convenient and novel approach. The major difficulty arises while delivering a drug through skin is its action as a natural barrier nature which makes it difficult for most drugs to penetrate into and permeate through it. Conventional topical formulations have not proved to be effective in dermal delivery of drug. Novel drug delivery systems bear great potential for dermal delivery. Among them lipidic and non-lipidic vesicular systems like liposome, noisome, transfersome and ethosome have been suggested to overcome the problems associated with conventional topical formulations. These vesicular systems were found to be more effective as they render controlled release of drug due to depot formation in skin and some were more effective in transdermal delivery. This article summarizes the potential of novel vesicular drug delivery carrier based dermal applications of the drug.
European Journal of Pharmaceutics and Biopharmaceutics, 2003
Liposomes have been extensively studied and suggested as a vehicle for topical drug delivery systems. However, the mechanism by which liposomes deliver drugs into intact skin is not fully understood. In the present study, we have tried to understand the mechanism of transport of hydrophilic drugs into the skin using liposomes. The effect of separation of the non-entrapped, hydrophilic fluorescent compound, carboxyfluorescein (CF), from liposomally entrapped CF was investigated by measuring the penetration of CF across human skin under nonocclusive conditions in vitro using Franz diffusion cells. The fluorescent dye, CF, was incorporated into the liposomes and applied onto the skin. After a 6 and 12 h incubation period, the amount of CF in the epidermal membrane and the full thickness skin was determined by fluorescence spectroscopy or by confocal laser scanning microscopy (CLSM). The liposomal formulation containing CF both inside and outside the vesicles showed statistically enhanced penetration of CF into the human stratum corneum (SC) as compared to the formulations containing CF only outside of the liposomes and CF in Tris buffer. The CLSM results revealed that the formulation in which CF was present outside the liposomes showed bright fluorescence intensity in the SC and very weak fluorescence in the viable epidermis. However, the CF in Tris buffer failed to show any fluorescence in the viable epidermis. The results indicated that phospholipid vesicles not only carry the entrapped hydrophilic substance, but also the non-entrapped hydrophilic substance into the SC and possibly into the deeper layers of the skin. q
Keywords: liposomes nanoparticles drug delivery systems transdermal drug delivery permeability percutaneous controlled release colloid skin lipids a b s t r a c t In the recent decade, skin delivery (topical and transdermal) has gained an unprecedented popularity, especially due to increased incidences of chronic skin diseases, demand for targeted and patient compliant delivery, and interest in life cycle management strategies among pharmaceutical companies. Literature review of recent publications indicates that among various skin delivery systems, lipid-based delivery systems (vesicular carriers and lipid particulate systems) have been the most successful. Ve-sicular carriers consist of liposomes, ultradeformable liposomes, and ethosomes, while lipid particulate systems consist of lipospheres, solid lipid nanoparticles, and nanostructured lipid carriers. These systems can increase the skin drug transport by improving drug solubilization in the formulation, drug partitioning into the skin, and fluidizing skin lipids. Considering that lipid-based delivery systems are regarded as safe and efficient, they are proving to be an attractive delivery strategy for the pharmaceutical as well as cosmeceutical drug substances. However, development of these delivery systems requires comprehensive understanding of physicochemical characteristics of drug and delivery carriers, formulation and process variables, mechanism of skin delivery, recent technological advancements, specific limitations, and regulatory considerations. Therefore, this review article encompasses recent research advances addressing the aforementioned issues.
Particle size of liposomes influences dermal delivery of substances into skin
International journal of pharmaceutics, 2003
In the present study, the influence of vesicle size on the penetration of two fluorescently labeled substances into the human skin was investigated. For the measurements either a hydrophilic fluorescent compound [carboxyfluorescein (CF)] or a lipophilic one [1,1'-dioctadecyl-3,3,3',3'-tertramethylindocarbo-cyanine perchlorate (DiI)] were encapsulated into vesicles. Liposomal formulations were prepared by extruding the vesicles through polycarbonate membrane filters with pores of different sizes. In vitro penetration studies into human abdominal skin were performed by using the Franz diffusion cell and a standardized skin stripping technique in attempt to find an optimum size for topical drug delivery by liposomes. Confocal laser scanning microscopy (CLSM) was used to visualize the effect of penetration ability of liposomal DiI. The maximum DiI fluorescence in the skin was observed with smaller liposomes of 71 nm diameter. The liposomes with a size of 120 nm diameter show...
Dermal delivery of drugs using different vesicular carriers: A comparative review
Asian Journal of Pharmaceutics, 2012
Many skin diseases are based in the dermal layer of the skin like-acne, alopecia, psoriasis, herpes zoster, etc. Conventional topical formulations have not proved to be effective in managing these conditions because of poor retention in the skin. Some formulations do not penetrate through the stratum corneum and some pass through the skin very quickly.Therefore, there is need to develop a strategy to deliver drugs to the dermis for better management of these conditions. Vesicular systems like liposomes, niosomes, ethosomes and transfersomes have been used by many researchers to localize drugs in the dermal layer and have been fairly successful. Some vesicles were found to be more effective in retaining drug to the skin and some were more effective in transdermal delivery. This article summarizes and compares the work done in the last decade on this topic and provides a conclusion.
VESICLES – MECHANISM OF TRANSDERMAL PERMEATION: A REVIEW
Transdermal drug delivery is an attractive alternative to conventional techniques for administration of systemic therapeutics. The major challenge in designing transdermal drug delivery systems is to overcome the natural transport barrier of the skin. One approach is the use of vesicle formulations. Liposomes were first shown to be of potential value for topical therapy by Mezei and Gulasekharam in 1980, since then investigation continued towards development of lipid vesicles as carriers for skin delivery of drugs. But still vesicles are considered as a controversial class of dermal and transdermal carriers. This review provides an overview of the effectiveness of conventional, deformable and ethosomal vesicles as drug delivery systems as well as their possible mode of action as permeation enhancers or transdermal drug carriers. Deformable liposomes and ethosomes penetrate stratum corneum, thus releasing their drugs or proteins into systemic circulation. Vesicles as carrier systems can give rise to development of novel transdermal drug delivery systems.
European Journal of Pharmaceutics and Biopharmaceutics, 2012
In this work, we focused on how composition and preparation method of vesicles might affect their morphological features and delivery performances. Penetration Enhancer-containing Vesicles, PEVs, vesicles containing a water miscible penetration enhancer (Transcutol Ò P; 10%, 20%, 30% v/v) and encapsulating diclofenac sodium, were formulated and compared with conventional liposomes. A cheap and unpurified commercial mixture of phospholipids, fatty acids, and triglycerides (Phospholipon Ò 50) was used, and the effects of this heterogeneous composition (along with the presence or absence of transcutol and the production method) on vesicle morphology, size, surface charge, drug loading, and stability were investigated. The variations in vesicle structure, bilayer thickness, and number of lamellae were assessed by TEM and Small and Wide Angle X-ray Scattering, which also proved the liquid state of the vesicular bilayer. Further, vesicles were evaluated for ex vivo (trans)dermal delivery, and their mode of action was studied performing a pre-treatment test and confocal laser scanning microscopy analyses. Results showed the formation of multi-and unilamellar vesicles that provided improved diclofenac delivery to pig skin, influenced by vesicle lipid composition and structure. Images of the qualitative CLSM analyses support the conclusion that PEVs enhance drug transport by penetrating intact the stratum corneum, thanks to a synergic effect of vesicles and penetration enhancer.
Elastic vesicles as drug carriers through the skin
Farmacia, 2010
Transdermal administration of drugs is generally limited by the barrier function of the skin. Vesicular systems are one of the most controversial methods for transdermal delivery of active substances. The interest in designing transdermal delivery systems was relaunched after the discovery of elastic vesicles: transferosomes and ethosomes. This paper presents the composition, manufacturing and characterization methods, mechanisms of penetration of transferosomes and ethosomes as transdermal delivery systems of active substances.