Facile transdermal delivery of upconversion nanoparticle by iontophoresis-responsive magneto-upconversion oleogel

Skin interaction, permeation, and toxicity of silica nanoparticles: Challenges and recent therapeutic and cosmetic advances

Silica nanoparticles (SNPs) received more attention with the emergence of nanotechnology with the aim and promise of becoming innovative drug delivery systems. They have been fulfilling this objective with excellence and nowadays they play a central role in biomedical applications. New SNPs application routes are being explored such as the epidermal, dermal, and transdermal routes. With that, novel models of synthesis, functionalization, and applications constantly appear. However, it is essential that such innovations are accompanied by in-depth studies on permeation, biodistribution, metabolization, and elimination of the generated by-products. Such studies are still incipient, if not rare. This article reviews significant findings on SNPs and their skin interactions. An extensive literature review on SNPs synthesis and functionalization methodologies was performed, as well as on the skin characteristics, skin permeation mechanisms, and in vivo toxicity assessments. Furthermore, studies of the past 5 years on the main therapeutic and cosmetic products employing SNPs, with greater emphasis on in vivo and ex vivo studies were included.

Recent advances in transdermal drug delivery systems: a review

Various non-invasive administrations have recently emerged as an alternative to conventional needle injections. A transdermal drug delivery system (TDDS) represents the most attractive method among these because of its low rejection rate, excellent ease of administration, and superb convenience and persistence among patients. TDDS could be applicable in not only pharmaceuticals but also in the skin care industry, including cosmetics. Because this method mainly involves local administration, it can prevent local buildup in drug concentration and nonspecific delivery to tissues not targeted by the drug. However, the physicochemical properties of the skin translate to multiple obstacles and restrictions in transdermal delivery, with numerous investigations conducted to overcome these bottlenecks. In this review, we describe the different types of available TDDS methods, along with a critical discussion of the specific advantages and disadvantages, characterization methods, and potential of each method. Progress in research on these alternative methods has established the high efficiency inherent to TDDS, which is expected to find applications in a wide range of fields.

Transdermal Delivery of Gold Nanoparticles by a Soybean Oil-Based Oleogel under Iontophoresis

Developing a facile mechanism for transporting nanoparticles across the whole skin by overcoming the stratum corneum is a challenging task. Herein, a stimuli-responsive and noninvasive transport of gold nanoparticles (AuNPs) has been reported through the fabrication of AuNP-incorporated soybean oil-based oleogels (AuG) using stearic acid as a gelator. A series of AuG was formulated by incorporating different proportions of AuNPs and a fixed amount of ciprofloxacin hydrochloride (drug) to establish that the composition with the highest concentration of AuNP (d-AuG4) was associated with the best iontophoretic response, validated via the corresponding in vitro drug release under AC field-induced iontophoresis. The sample d-AuG4 exhibited both drug and AuNP permeation across the whole pig ear skin thickness within as early as 1 h under the iontophoresis condition. With relevant control experiments, it was shown that the transport of AuNPs through the stratum corneum tissue and across the whole skin was possible upon the simultaneous fulfillment of two conditions: the presence of a skin permeation enhancer (stearic acid) within the oleogel and iontophoresis. While the literature reported that the permeation time for any free inorganic nanoparticle through the full-skin thickness varied within a few days, the permeation enhancement technique developed here reduced the corresponding delivery time for the AuNPs to a few hours. The extent of AuNP permeation that occurred in the microgram (per cm^-2) scale was found to be affected by the duration of iontophoresis, suggesting that AuNPs' rapid transdermal entry can be simultaneously triggered and modulated by iontophoretic conditions.