Formula 1. SPF 20 sun lotion

A.
Xanthan Gum (Keltrol RD, S. Black), 0.10% w/w

B.
Water (aqua), qs

C.
Propylene Glycol, 4.00

D.
Glyceryl Stearate (and) PEG-100 Stearate (Arlacel 165 FL, Croda), 6.00
Sorbitan Stearate (Span 60, Croda), 0.50
Polysorbate-60 (Tween 60, Croda), 2.70
Cetearyl Alcohol (Crodacol C S90 EP, Croda), 1.00
Paraffinum Liquidum (Mineral) Oil, 8.00
Ethylhexyl Palmitate (Crodamol OP, Croda), 2.50
Polydimethylsiloxane (Dow Corning 200 Fluid, 350 cst, Dow Corning), 2.00
VP/Eicosene Copolymer (Unimer U-15, Induchem), 1.00

E.
Titanium Dioxide (and) C12-15 Alkyl Benzoate (and) Polyhydroxystearic Acid (and) Stearic Acid (and) Alumina (Solaveil XT-100, Croda), 18.00

F.
Preservative, qs

Procedure: Disperse A into B. Add C to AB and heat to 75–80°C. Separately heat D to 75–80°C. Add E to D with stirring and maintain temperature. Add DE to ABC with intensive stirring. Homogenize for 2 min. Stir and cool to RT, adding F to batch below 40°C. Appearance = white lotion; viscosity = 12,360 mPas (Brookfield RVDV1, spindle 4, 5 rpm, 1 min); in vivo SPF = 24; UVA/UVB ratio = 0.79; label SPF = 20; in vitro UVAPF = 8; ratio label SPF UVAPF = 2.5.