- Posted by Mark Goins
- On April 21, 2017
- 0 Comments
- laboratory, stability
As the weather warms and the sun peeks out from behind the clouds, thoughts turn to outdoor activities and enjoying the pleasant weather. What follows is the inevitable need for sunscreen/sunblock products to help keep consumers and their families safe. This requires sunscreen product manufacturers to perform due diligence to assure the products they place on store shelves provide the level of protection indicated.
This process involves many steps. First of all, testing to determine that active sunscreen ingredients meet acceptable standards of raw material identity and purity according to USP/NF guidelines, prior to formulating them into the product(s). Having a qualified laboratory verify the active ingredients (e.g. Octinoxate, Oxybenzone, Avobenzone, Octisalate, Octocrylene, Homosalate, Zinc Oxide, etc.) meet the standards defined by USP/NF is an important step in assuring the quality of the finished products. This can be accomplished by periodically sending raw material lots to a laboratory to perform the USP/NF Monograph(s) or by requiring the raw material supplier to provide a Certificate of Analysis with the raw material shipments. Even if the supplier provides this C of A, it is recommended to occasionally have lots independently tested for verification.
Once the Sun Protection Factor (SPF) of a formulation has been determined, testing random lots of finished product is another step to assure product integrity. A qualified laboratory can develop and validate an assay that quantifies the levels of the active ingredient(s) and this assay is then utilized to monitor the levels of the actives as finished products are produced. A validated assay is required for each product type, even if the active ingredient(s) are the same if the excipients are varied, a targeted assay must be developed. An experienced lab can save time and money by using previously developed assays as building blocks to develop and validate the specific assay for each product type.
Sunscreen products often, sit on shelves during the colder winter, fall and even springtime seasons, and only when the temperature rises do consumers reach for these protective products. That is why determining the “best if used by” or expiration dates of the product is a vital step in providing the end user with the information they need to determine if the product is still viable and effective. This data is generated by performing a rigorous stability study that monitors the stability of active ingredient(s) and therefore the sun protection efficacy of the product. This is accomplished by storing the product over time to determine when the active ingredient levels drop to the point of reducing the SPF and thereby invalidating the SPF indicated on the product label. This data can be generated in a relatively short period of time by storing the product(s) at accelerated temperature and humidity, while also performing the real-time portion of the stability protocol. Consumers rely on this information to protect themselves and their families, so it is crucial that testing is performed following protocols established by established standards groups such as the International Council on Harmonization (ICH).
Microbiological testing can also be performed during the stability study to monitor the antimicrobial efficacy of any preservatives in the product as well as various chemical tests that may indicate the quality of the product such as viscosity, appearance, odor, pH, etc.
The potential harm done by sun exposure has been well documented. That is why it is imperative that sunscreen product manufacturers perform recommended due diligence measures to provide consumers with the information they need to protect themselves when enjoying the warm summer months. Product types providing sun protection can include lotions, sprays, cosmetics, lip balms, and many others.