Retinoid-based nanocosmetics show promising anti-aging benefits, yet researches flag lack of evidence

17 Oct 2022 --- A Slovenia-based study has unveiled the “promising potential” of nanoformulations containing retinoids for topical delivery while underscoring a lack of large-scale research in the area. The use of nanotechnology in anti-aging cosmetics is the fastest-growing segment in the skin care industry, the researchers state.

The most commonly used retinoids, such as retinol (vitamin A), retinaldehyde and retinyl palmitate, are contained in cosmeceuticals regulated as cosmetics. Since clinical efficacy studies are not required for marketing cosmetic formulations, the researchers state that there are concerns about the efficacy of these retinoids.

From a formulation perspective, retinoids pose a challenge to researchers due to their proven instability, low penetration and potential for skin irritation.

“Novel delivery systems based on nanotechnology are being developed to overcome the limitations of conventional formulations and improve user compliance,” the study published in Advances in Therapy informs. 

“In general, there is a lack of evidence from properly designed clinical trials to support the claimed efficacy of the most commonly used retinoids as anti-aging agents in cosmeceuticals. The promising potential of retinoid nanoformulations requires a more comprehensive evaluation with additional studies to support the preliminary findings.”There is a need for additional studies that will provide new information and insights to support the use of different retinoids in anti-aging treatments.

Nanotechnology for stability?
The researchers say that nanotechnology approaches are used to improve the chemical and photochemical stability of the active ingredient, increase penetration, modify its release from the formulation and achieve satisfactory efficacy with minimal skin irritation.

The nanoformulations include lipid-, polymer- and metal-based nanosystems, among which lipid-based delivery systems are considered to be advantageous owing to their low toxicity, high drug loading capacity and biodegradability. 

Lipid-based systems also provide large-scale manufacturing, high drug loading capacity, biodegradability, large-scale manufacturing and diverse chemical and formulation landscape.

“Although nanomaterials may be present in formulations as active ingredients, rheology modifiers or carriers, their use and role in marketed cosmetics generally remain undisclosed because of the current mistrust toward their application,” the study highlights.

The researchers elucidate that even though different types of nanocarriers with tretinoin have been developed, there is no commercially available nanoformulation with the acid on the market to date. Tretinoin is the most potent and best-studied retinoid for its anti-aging properties and is considered the gold standard for clinically effective topical retinoids used in anti-aging treatments.

After reviewing existing literature on the clinical efficacy and safety of nanoformulations compared to conventional formulations, the study concludes that “the risk-to-benefit ratio of the topical nanoformulations is evaluated on a case-by-case basis because of the lack of harmonized quality standards and regulatory frameworks.”

Benefits of retinol
The retinoid family consists of both naturally occurring and synthetic analogs of retinol.

The research informs that the anti-wrinkle effects of topically applied formulations containing retinoids are based on promoting keratinocyte proliferation and collagen synthesis, improving the epidermal barrier and inhibiting collagen degradation, transepidermal water loss (TEWL) and metalloproteinase activity.

“Tretinoin, alitretinoin, adapalene, tazarotene, bexarotene and trifarotene are found in topical formulations approved as medicines for various indications such as acne or psoriasis. In addition, tretinoin and tazarotene are the only retinoids with approved indications for treatment of photoaged skin as an adjunctive treatment,” the study states.From a formulation perspective, retinoids pose a challenge to researchers due to their proven instability, low penetration and potential for skin irritation.

Although retinoids are among the most commonly used anti-aging and depigmenting ingredients in cosmetics, their use is associated with the issues of low penetration and common side effects such as skin irritation due to their physicochemical properties and proven instability.

The side effects of topically applied retinoids include “retinoid dermatitis” or skin irritation at the application site, ocular discomfort and dry eye syndrome, and potential teratogenicity (abnormal morphological development).

Nanocosmetics research
Previously, a review of over ten valuable nanoparticles and nanoliposomes (UV filters and delivery vehicles), followed by EU, US, Chinese and Australian regulatory opinions on the use of nanocosmetics raised concerns over health issues due to toxicity risks. 

Other concerns outline “large-scale production and conversion of nanocarriers dosage to final cosmetic form (cream/gel) which sometimes lead to drug leakage or change in particle size, thus affecting its skincare efficiency.”

In another research, nanoparticles like silver and zinc oxide, used in cosmetics, were found to cross the blood-brain barrier (BBB) and enter the brain as particles and dissolved ions – depending on the size, shape and exposure concentration. Smaller and spherical particles cross the BBB more easily than wire-shaped particles. 

Edited by Radhika Sikaria