Development and Characterization of New Topical Hydrogels Based on Alpha Lipoic Acid—Hydrotalcite Hybrids

Highly Hydrophilic TiO2 Nanoparticles as Stabilizers of Pickering Emulsions with Photosensitive Lipophilic Compounds: Synthesis and Application

Pickering emulsions are a very promising system for encapsulating and photoprotecting active ingredients. The highest photoprotection efficiency can be achieved when bare TiO2 nanoparticles are used as stabilizers. However, the main problem when using highly hydrophilic TiO2 nanoparticles is their inability to adsorb at the oil-water interface. Here, we developed emulsions stabilized by bare, highly hydrophilic TiO2 nanoparticles for the encapsulation and photoprotection of active lipophilic compounds. Emulsion stabilization occurs due to the formation of hydrogen bonds between hydroxyl groups on the particle surface and the carbonyl groups of the oil molecules. The stability and rheological properties of emulsions are explained by the properties of the initial hydrosols. The resulting Pickering emulsions demonstrated effective UV protection of α-lipoic acid. Our results pave the way for the formulation of Pickering emulsions with a widely used cosmetic oil and show for the first time the possibility of photoprotection of a lipophilic active substance using unmodified TiO2 nanoparticles.

Synthesis and Evaluation of Metal Lipoate Adhesives

The development of new bioadhesives with integrated properties remains an unmet clinical need to replace staples or sutures. Current bioadhesives do not allow electronic activation, which would allow expansion into laparoscopic and robotic surgeries. To address this deficiency, voltage-activated adhesives have been developed on both carbene- and catechol-based chemical precursors. Herein, a third platform of voltage-activated adhesive is evaluated based on lipoic acid, a non-toxic dithiolane found in aerobic metabolism and capable of ring-opening polymerization. The electro-rheological and adhesive properties of lithium, sodium, and potassium salts of lipoic acid are applied for wet tissue adhesion. At ambient conditions, potassium lipoate displays higher storage modulus than lithium or sodium salt under similar conditions. Voltage stimulation significantly improves gelation kinetics to Na- and K-lipoates, while Li-lipoate is found to not require voltage stimulation for gelation. Lap shear adhesion strength on wetted collagen substrates reveals that the synthetic metal lipoates have comparable adhesion strength to fibrin sealants without viral or ethical risks.

Starch-based sustainable hydrogel loaded with Crocus sativus petals extract: A new product for wound care

The aim of the present study was to valorize Crocus sativus petals, the main waste deriving from saffron stigma harvesting, as source of bioactive molecules to be used in health field. Three different dry extracts were prepared by eco-friendly methods (maceration and ultrasound bath assisted maceration) using saffron petals as raw material and ethanol 70 % either ethanol 96 % as extraction solvents. A preliminary evaluation of the antioxidant activity (measured by ABTS*⁺, DPPH* and FRAP) highlighted that the most suitable extraction solvent is represented by ethanol 70 %. By in vitro studies on keratinocytes emerged that the extract obtained by maceration (rich in gallic and chlorogenic acids) stimulates their growth in a safe concentration range (0.02-0.4 mg/mL) suggesting a potential application in skin diseases such as superficial wounds. Due to the low manageability, the extract was firstly supported on corn starch powder particles and then formulated as starch gel. The obtained formulation showed both suitable rheological properties and spreadability necessary for an easy and pain free application on damaged skin. Moreover, in vitro microbiological studies of starch gel demonstrated antimicrobial activity toward S. epidermidis and self-preserving capacity.

Nanocarriers as Active Ingredients Enhancers in the Cosmetic Industry-The European and North America Regulation Challenges

“Flawless skin is the most universally desired human feature” is an iconic statement by Desmond Morris. Skin indicates one´s health and is so important that it affects a person’s emotional and psychological behavior, these facts having propelled the development of the cosmetics industry. It is estimated that in 2023, this industry will achieve more than 800 billion dollars. This boost is due to the development of new cosmetic formulations based on nanotechnology. Nanocarriers have been able to solve problems related to active ingredients regarding their solubility, poor stability, and release. Even though nanocarriers have evident benefits, they also present some problems related to the high cost, low shelf life, and toxicity. Regulation and legislation are two controversial topics regarding the use of nanotechnology in the field of cosmetics. In this area, the U.S. FDA has taken the lead and recommended several biosafety studies and post-market safety evaluations. The lack of a global definition that identifies nanomaterials as a cosmetic ingredient is a hindrance to the development of global legislation. In the EU, the legislation regarding the biosafety of nanomaterials in cosmetics is stricter. “The cost is not the only important issue, safety and the application of alternative testing methods for toxicity are of crucial importance as well”.

Aged related human skin microbiome and mycobiome in Korean women

We examined differences in the skin microbiome of two separate age groups to find key microbial and skin physiological indicators associated with aging. We recruited healthy Korean women 19–28 years old (Y-group) and 60–63 years old (O-group) and evaluated their cheek and forehead skin microbiome, including bacteria and fungi. The microbiome was significantly different by age group, with bacterial and fungal communities displaying higher alpha-diversity in the O-group than in the Y-group. We identified amplicon sequence variants affiliated with Cutibacterium and Lactobacillus and fungi Malassezia restricta as microbial biomarkers showing significant differences between the Y and O-group. There are more microbial communities and metabolic processes related to skin health in the Y-group than in the O-group, and there are more microbial interactions to increase the stability of the network structure of the skin. Skin physical metadata, including transepidermal water loss and sebum content, differed by two age groups. The crucial skin microbes, skin physical parameters, and microbial network found through this research will be useful key indicators in associating skin aging and skin microbiome research.

Evaluation of Dissolution Profiles of a Newly Developed Solid Oral Immediate-Release Formula Containing Alpha-Lipoic Acid

Alpha-lipoic acid (ALA, thioctic acid), a naturally-occurring essential dithiol compound, has become a common ingredient in many pharmaceutical and food supplement products (FSP), used in oxidative stress-dependent pathologies; oral bioavailability of ALA is limited by pharmacokinetic particularities that reduce its therapeutic efficacy-reduced solubility, lack of gastric stability and hepatic degradation, doubled by formulation hinders. The objectives were to develop a solid oral 600 mg ALA FSP to obtain an optimal pharmaceutical profile compared to a reference listed drug (RLD) with a similarity factor f2 50. A comparative dissolution study was performed; an HPLC method was used for ALA quantification. After planning combinatory simulations (formulation stage), two prototype formulas (#1 and #2) were manufactured and further optimized by adjusting ALA physical characteristics and the excipients quantities (#3 and #4) in order to achieve the Quality Target Product Profile. A misshapen of ALA’s in vitro release was observed for #3 Formula (f2 = 31.6); the optimal profile was obtained for Formula #4 (f2 = 58.5). A simple quantitative formula is not enough to assure good ALA bioavailability; the formulation needs multiple compounding modulations under physicochemical compatibility algorithms, with multiple dissolution profiles testing back-ups. It is essential to ensure a formulation with an in vitro dissolution comparable with the RLD, allowing the compound to reach its target level to assure the optimum claimed antioxidant activity of ALA at the cellular level, even for food supplement formulations.

Layered double hydroxides are still out in the bloom: Syntheses, applications and advantages of three-dimensional flower-like structures

Layered double hydroxides (LDHs) have received great attention for years in numerous fields. Controlled and flexible layer composition, as well as the vast assortment of possible anionic guests, and easy adaptability for multipurpose applications, have been some of the many reasons behind their extraordinary success. However, versatility does not only involve the composition or the dimensions of the crystals but also their morphology. Aside from conventional hexagonal, flat structures, three-dimensional assemblies have been reported with architectures closely resembling those of flowers. The possibility of interconnecting the LDH nanosheets in rosette-like geometries has arisen the interest in finding new ways to control, modulate, and guide the particle growth obtaining hierarchical structures to be adapted to specific targets. This review is focused on describing the different strategies implemented to build flower-like assemblies, and on investigating their applications, looking for specific advantages of the use of a three-dimensional architecture over a bi-dimensional one.

Polymeric Bioadhesive Patch Based on Ketoprofen-Hydrotalcite Hybrid for Local Treatments

Ketoprofen (KET) represents one of the most common drugs used in the topical treatment of pain and inflammations. However, its potential is rather limited due to the very low solubility and photochemical instability. The local administration of KET by conventional products, such as gels, emulgels, creams, and foams, does not guarantee an efficacious and safe treatment because of its low absorption (due to low solubility) and its sensitivity to UV rays. The photodegradation of KET makes many photoproducts responsible for different adverse effects. In the present work, KET was intercalated into the lamellar anionic clay ZnAl-hydrotalcite (ZnAl-HTlc), obtaining the hybrid ZnAl-KET with improved stability to UV rays and water solubility in comparison to the crystalline form (not intercalated KET). The hybrid was then formulated in autoadhesive patches for local pain treatment. The patches were prepared by casting method starting from a hydrogel based on the biocompatible and bioadhesive polymer NaCMC (Sodium carboxymethycellulose) and glycerol as a plasticizing agent. The introduction of ZnAl-KET in the patch composition demonstrated the improvement in the mechanical properties of the formulation. Moreover, a sustained and complete KET release was obtained within 8 h. This allowed reducing the frequency of anti-inflammatory administration, compared to the conventional formulations.

New Technological Approach for Glycyrrethic Acid Oral and Topical Administration

Background:

18β- glycyrrhetinic acid (Gly) is the major bioactive component of licorice roots and rhizomes of the Glycyrrhiza glabra species. It shows many activities such as antiviral, anti-inflammatory, antioxidant, antimicrobial, and antifungal, however, its use in the health field is very limited due to the low water solubility.

Methods:

This paper deals with the development of a new technological approach for Gly dissolution rate enhancement. It consists of Gly intercalation (guest) in the interlamellar spaces between the inorganic spaces (host) of the anionic clays “hydrotalcites” (HTlc) to obtain hybrids MgAl-HTlc-Gly and ZnAl-HTlc-Gly. Gly can find applications in both systemic and local therapies, thus advantages of the use of the hybrids in these two fields were investigated.

Results:

Gly dissolution rate from hybrids in the intestinal environment, site in which it is preferentially absorbed, resulted enhanced (ZnAl-HTlc-Gly > MgAl-HTlc-Gly) compared to the crystalline form, thereby, making them suitable for oral administration as dry powder in hard capsules.

:

For a local therapy, bioadhesive, vaginal emulgels loaded with the hybrids were developed. These showed suitable mucoadhesive property to the vaginal mucosa, necessary to prolong the residence time in the application site. The emulgel containing ZnAl-HTlc-Gly showed a faster and higher release profile than that containing MgAl- HTlc-Gly.

Conclusions:

The obtained results suggest that Gly intercalation into HTlc, especially in ZnAl-HTlc, allows to enhance Gly dissolution when the hybrids are formulated both as oral or topical products.