Transdermal drug delivery offers an attractive alternative to the conventional drug delivery methods of oral administration and injection. However, the stratum corneum acts as a barrier that limits the penetration of substances through the skin. Application of ultrasound to the skin increases its permeability (sonophoresis) and enables the delivery of various substances into and through the skin. Ultrasound has been used extensively for medical diagnostics and to a certain extent in medical therapy (physiotherapy, ultrasonic surgery, hyperthermia). Nevertheless, it has only recently become popular as a technique to enhance drug release from drug delivery systems. A number of studies suggest the use of ultrasound as an external mean of delivering drugs at increased rates and at desired times. This review presents the main findings in the field of sonophoresis, namely transdermal drug delivery and transdermal monitoring. Particular attention is paid to proposed enhancement mechanisms and trends in the field of topical and transdermal delivery.

Background: Nanoparticle formulations development for anti-aging treatment is increasing due to their multifunctional properties. These nanotechnological strategies can target cellular/ molecular pathways of the skin affected by the aging process. However, a review of these strategies is required to discuss their efficacy/safety and establish the needs for further research.Objective: Innovative nanotechnological advances for skin anti-aging/rejuvenation are summarized and discussed in this work.Method: The information in this review was extracted from recent and relevant studies using nanotechnology for anti-aging treatment from scientific databases.Results and Discussion: Results show an enhanced skin anti-aging effect of actives-loaded nanoparticles of next generation (nanostructured lipid carriers, fullerenes, transfersomes, protransfersomes, niosomes, ethosomes, transethosomes, glycerosomes, phytosomes) compared with nanocarriers of first generation or conventional formulations. Anti-aging active ingredients such as, flavonoids (rutin, hesperidin, quercetagetine, quercetin, epigallocatechin-3-gallate, myricetin, silibinin, curcuminoids, isoflavones); vitamins (E, D3, CoQ10); acids (hyaluronic, ascorbic, rosmarinic, gallic); extracts (Citrus sinensis, Tagetes erecta L., Achillea millefolium L., Citrus aurantium L., Glycyrrhiza glabra L., Aloe vera, propolis earned by Apis mellifera); and other compounds (adenosine, beta-glucan, heptapetide DEETGEF, resveratrol, cycloastragenol, melatonin, botulinum toxin, grapeseed oil), have been successfully entrapped into nanoparticles for skin rejuvenation. This encapsulation has improved their solubility, bioavailability, stability, permeability, and effectivity for skin anti-aging, providing a controlled drug release with minimized side effects.Conclusion: Recent studies show a trend of anti-aging herbal active ingredients-loaded nanoparticles, enhancing the moisturizing, antioxidant, regenerating and photoprotective activity of the skin. Suitable safety/shelf-life stability of these novel formulations is key to a successful translation to the clinic/industry.

Emulsification-diffusion method is often used to produce polymeric nanoparticles. However, their numerous and/or lengthy steps make it difficult to use widely. Thus, a modified method using solvent blends (miscible/partially miscible in water, 25–100%) as the organic phases to overcome these disadvantages and its design space were investigated. To further simplify the process, no organic/aqueous phase saturation and no water addition after the emulsification step were performed. Biodegradable (PLGA) or pH-sensitive (Eudragit^® E100) nanoparticles were robustly produced using low/medium shear stirring adding dropwise the organic phase into the aqueous phase or vice versa. Several behaviors were also obtained: lowering the partially water-miscible solvent ratio relative to the organic phase or the poloxamer-407 concentration; or increasing the organic phase polarity or the polyvinyl alcohol concentration produced smaller particle sizes/polydispersity. Nanoparticle zeta potential increased as the water-miscible solvent ratio increased. Poloxamer-407 showed better performance to decrease the particle size (~50 nm) at low concentrations (≤1%, w/v) compared with polyvinyl alcohol at 1–5% (w/v), but higher concentrations produced bigger particles/polydispersity (≥600 nm). Most important, an inverse linear correlation to predict the particle size by determining the solubility parameter was found. A rapid method to broadly prepare nanoparticles using straightforward equipment is provided.

Aims: Biodegradable polymeric microneedles containing atorvastatin calcium were developed in order to improve the percutaneous absorption of the drug, useful for the treatment of hypercholesterolemia. Background: The use of physical enhancers like microneedles have shown good results to increase the delivery of drugs through the skin, the use of microneedles has very important advantages for transdermal drug delivery, for example, they are painless, easy to use and safe, they increase time interval of drug activity, dose, and reductions in adverse reactions, they also offer, the facility to remove the system instantly of the skin. Objective: Develop polymer microneedles loaded with a calcium atorvastatin and evaluate them by Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), bioadhesion, postwetting- bioadhesion, breaking strength, drug release test and in vitro percutaneous absorption studies to demonstrate the use of microneedles atorvastatin is able to cross the skin. Methods: The microneedles were made with poly (methyl vinyl ether-alt-maleic acid) as biodegradable polymer using the technique of casting in solution in a mold. After solidification these microneedles were characterized by Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), bioadhesion, post-wetting-bioadhesion, breaking strength, drug release test and in vitro percutaneous absorption studies. Results: In general, the performances were satisfactory for optimal formulation in terms of DSC with no interactions between drug and excipients, SEM shows microneedles with a conical shape, bioadhesion of 1570 g.f, post wetting-bioadhesion of 1503.4 g.f, breaking strength of 1566.7g.f that is sufficient to disrupt Stratum corneum, good drug release and a flux of 33.4 μg/cm2*h with a tLag of 15.14 h for the in vitro percutaneous absorption. Conclusion: The results indicate that it is possible to generate microneedles to increase the percutaneous absorption of calcium atorvastatin transdermally, with the potential to be used as an alternative to the oral route for the treatment of dyslipidemias.