The group of retinoids is composed by retinol (vitamin A) and its natural derivatives, such as retinal, retinoic acid and retinyl esters, and synthetic derivatives, such as adapalene and tazarotene. Retinoids are necessary to the organism and are involved in many biological processes: embryogenesis, reproduction, eyesight, growth, differentiation, proliferation and apoptosis. In the 1970s, retinoids were introduced to treat skin disorders and, since then, their use in cosmetic products has gradually increased. Through its significant action in the in cell differentiation and proliferation process and collagen stimulation, retinoids are widely used by the cosmetic industry for antiaging, peeling and acne treatment.
The use of retinoids in cosmetic products, however, presents some difficulties such as their stability in formulations. Due to its high rate of degradation against oxygen, light and heat and its fat-soluble character, there may be limitations regarding formula and packaging, in addition to specific care during the manufacturing and packaging process. There are several studies demonstrating variations in the stability of retinoids in different formulations, but there are still few studies evaluating the impact of packaging on cosmetic products containing retinoids. Most articles address the issue of stability of vitamin A (or retinol) in food products. In this way, the present study aims to evaluate the stability of cosmetic formulation containing retinol in different types of packaging and to observe the impact of packaging alone in retinol protection.
For the study, was produced a gel cream containing 0.2% nanoencapsulated retinol on laboratory scale. The same batch of formulation was packaged in five types of packaging: plastic pump tube packaging 40g, plastic ophthalmic tube 40g, opaque glass pump bottle dispenser 30g, amber glass jar 40g and clear glass jar 100g. The samples were stored at 5°C, 23°C and 40°C for 90 days. Retinol content was measured using high performance liquid chromatography at 0, 30, 60 and 90 days.
More stable results were observed in the plastic pump tube packaging wtih above 80% retinol recovery in all conditions until the end of the 90 days. The lowest values ​​were found for the amber glass jar packaging, which in 30 days at 40°C condition had only 41% of retinol recovery, reaching 2.97% in the same condition in 90 days. The other packages obtained intermediate results, reaching values ​​above 34% or 50% in all conditions at the end of 90 days.
Based on the results, it is possible to observe the correlation of packaging with widder opening and smaller volumetry (40g jar) to lower results of retinol, while packaging with narrow opening and smaller volumes (tubes, pump bottle dispenser) had better results. This is mainly related to the greater exposure to oxygen in containers such as pot, which favors the degradation of retinol. It is also interesting to note that despite being a 100g pot, the larger volume was positive for greater protection of retinol and the results obtained in this package are very close to the plastic ophthalmic tube and pump bottle. The results demonstrate the relevance of packaging in the development of products containing retinoids, demonstrating that the shape, opening and volumetry of the packaging can significantly influence the preservation of retinol in the formula, according to very different results obtained for each packaging.
The study intends to collaborate with the decision-making process in the development of cosmetic products containing retinoids, suggesting that adequate formula and packaging can bring better results in protecting retinoids over time, avoiding higher investments in specific manufacturing and packaging processes.