J. Cosmet. Sci., 71, 291–302 (September/October 2020) 291 RiceSorb® as Talcum Substitute for Loose Face Powders: Formulation and Characterization AR PAPAT SIRIWARIN, PEERAPAT CHIDCHAI, DUANGKHAE MANEENUAN, NATTHA KAEWNOPPARAT, and SARUNYOO SONGKRO, De partment of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Songkhla 90112, Thailand (A .S., P.C., D.M., N.K., S.S.), Drug Delivery System Excellence Center, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand (D .M., N.K., S.S.) Accepted for publication April 25, 2020. Sy nopsis Ex cessive and daily inhalation of talcum, a main ingredient of face powders, causes pulmonary talcosis, which has led to the replacement of talcum with safer natural ingredients. RiceSorb®, or Oryza sativa starch from Japanese rice, was used as an alternative owing to its nontoxic and excellent oil absorption capacity. The objectives of the present work were to formulate loose face powders from RiceSorb® and to investigate the physicochemical properties of the prepared formulations. Five formulations of loose face powders were prepared by varying the ratios between talcum and RiceSorb®: 4:0 (FT0), 3:1 (FT1), 1:1 (FT2), 1:3 (FT3), and 0:4 (FT4). The physicochemical properties were evaluated mainly based on USP 41 and NF 36 such as morphology by using a scanning electron microscope, bulk density, fl ow property (angle of repose), moisture content (MC), and pH. The stability of the formulations were also performed at ambient temperature and 45°C for 2 months. The formulations had pH 6.90–8.62, bulk density 0.33–0.49 g/ml, and an angle of repose 30°–41°. Overall, the formulations which contained only RiceSorb® (FT4) or higher proportion of RiceSorb®(FT3) had fi ner particles, lower bulk density, pH, and angle of repose than those of the formulations containing high proportion of talcum: FT0 and FT1. Under storage conditions for 2 months, the formulations containing high proportion of RiceSorb® exhibited noticeably increased MC and angle of repose. However, the other physicochemical properties were somewhat the same. The present results suggest the applicability of RiceSorb® for loose face powders. INTRODUCTION H uman beings have been decorating their faces with rudimentary cosmetics such as face powders since ancient times. Simple powdered materials available in local areas such as grinded wheat, grinded rice, and white pigments were commonly used to whiten their faces. After the industrial revolution in the 19th century, more sophisticated substances have Address all correspondence to Sarunyoo Songkro at sarunyoo@pharmacy.psu.ac.th.

JOURNAL OF COSMETIC SCIENCE 292 been formulated for modern face powders. Face powders are applied on the face or the neck to enhance skin’s natural beauty and to cover wrinkles or blemishes such as dark spots, freckles, and acne scars (1). In general, modern face powders can be classifi ed into two types: loose face powders and compact face powders. The main difference between these two forms is binding agents which are very important ingredients in compact face powders (2). In the current work, we focused on the loose face powders owing to the rela- tively easy preparation process. Modern face powders are composed of a variety of materi- als which are blended together to achieve the desired characteristics: covering power, adhesion, absorbency, slip, and bloom. Generally, the mainly used ingredient of loose face powders is talcum or talc, a hydrated magnesium silicate (1,2). Although talcum im- proves slip and adhesiveness of face powders to the skin, long-term daily inhalation of talcum has been shown to cause pulmonary talcosis (3,4). Thus, alternative materials for talcum substitutes have been explored. Among them, s tarches are of our interest because they are skin-friendly cosmetic ingredients and thus suitable for sensitive skin (5). Starch fl ours such as corn starch and rice starch are also basic substances for face powder formulations. Generally, they are used as covering power owing to their fi neness. Among several starches, rice starch is drawing attention because of its safety and unique properties. RiceSorb®, Oryza sativa starch derived from peel seeds of Japanese rice, is an interesting sub- stance for cosmetic application. Developed in France, RiceSorb® is white fi ne pow- ders with particle sizes 10 μm. Protein, fats, and impurities are removed to obtain RiceSorb®. It is highly purifi ed and sterilized. RiceSorb® is applicable for face powder formulae because of its exceptional absorption capability, especially for oily liquids, and its small size granules. As a result, a possibility of using RiceSorb® as talcum replace- ment had been evaluated. Interestingly, RiceSorb® acts as an oil absorbent that does not absorb moisture/water from the skin (6). This makes RiceSorb® suitable for oil- control products. Talcum can cause skin dryness because it not only absorbs oils but also absorbs water/moisture from the skin. Apart from the power base (white or off-white materials), color shades of face powders are considerably important factors. The color shades of face powders are dependent on the skin tones and fashion. Synthetic colors (e.g., pigments or lakes) have been usually used for formulating face powder preparations. In the current work, the coloring agent used for the prepared loose face powders was obtained from a plant extract (natural colorant). Plant extracts have been generally incorporated into the skin care products because of the awareness of harmful synthetic chemical substances (7). Tamarindus indica fruit pulp extract in powder form was used as a colorant in the present work. Widely cultivated in tropical countries, Tamarindus indica or tamarind has been shown to pos- sess several benefi cial medicinal properties (8). Afterward, its application in a cosmetic fi eld has been recognized. The tamarind extract powder has light brown–yellow range of colors, which suitably match the natural skin tones of Asian women. Like many plant extracts, it possesses antioxidant property because of the presence of several or- ganic acids such as tartaric acid, citric acid, and malic acid (9). Color bleeding due to perspiration is not expected because RiceSorb® in the formulation could absorb mois- ture (e.g., sweat). Laboratory-scale preparation was carried out using a mortar and a pestle to mix all ingredients together. The main objectives of the present study were to (i) formulate the loose face powders using RiceSorb® as a substitute for talcum and (ii) investigate the physicochemical