Abstract: Formulating with Inorganic sunscreens

Hani Fares*, Ph. D. and Anthony Adamo, Donald Prettypaul. and Diane Kennedy

The proposed rules published by the FDA in the Federal Register in February 2019 had the biggest impact on sunscreen formulations since the publication of the first tentative monograph in August1978.  In this presentation, the MUsT (Maximal Usage Trial) study conducted by the FDA that led to the proposed changes will be discussed as well as the impact of those changes on future formulations.

In addition, an in-depth review of formulation strategies with zinc and titanium oxides will be presented.  Methodologies used to screen various types of inorganic sunscreens such as zeta potential, contact angle, particle size analysis, SEM microscopy and Hegman gauge will be presented and compared.  The effect of particle size on SPF and skin whitening will be discussed.  Differences between formulating inorganic sunscreens in O/W and W/O emulsions and their impact on water resistance and formulation stability will be reviewed.  The addition of polymers and SPF boosters to increase SPF and water resistance will be presented along with some in vivo SPF testing data.

The work presented will enable formulators to get a head-start to adapt their formulations to the guidelines set forth by the FDA and prepare them to formulate efficiently with inorganic sunscreens.

presenting author

Hani Fares
senior director
Ashland personal care






Dr. Fares started his career in personal care studying the effect of solvents on sunscreen chemicals.  His interest in skin drug delivery especially from polymeric matrices grew during his graduate work at Rutgers, where he received his Ph. D.

Dr. Fares worked at Block Drug and GlaxoSmithKline where he held positions in research and development in the areas of skincare and oral care.  After that, he joined L’Oreal where he held several positions of increasing responsibility leading to AVP of skincare.  He is currently the Senior Director of skincare and oral care at Ashland Specialty Ingredients.  Dr. Fares is the author of many publications, and patents and made many presentations in national and international meetings in the areas of suncare, skincare, and oral care.  Dr Fares chairs the NYSCC scientific committee and has won multiple awards in the area of sun care and polymer chemistry.