Table 9.

A RAT²IO module for prototype fabrication.

Objectives	Input information	Activities	Tools	Resources	Time (week)	Output information
4.4.1 Develop a base case formula	Technical specifications	Measure physical and chemical properties of active ingredients	–	Formulators	2	Physical and chemical properties of active ingredients
	Product microstructure	Choose supporting materials		Scientists		Base case formula
	Selection guidelines for supporting materials	Design prototyping procedure
	Government regulations on prohibited materials
	Sample recipes/formulae
	Ingredients checklist
4.4.2 Prepare a stable prototype cream	Heuristics for formula modification	Prepare cream prototype	Stir plates	Formulators	20a	Prototype cream formula, fabrication procedure and a sufficient amount of sample
	Physical and chemical properties of active ingredients	Check particle size distribution	Hand-held mixers	Scientists
	Base case formula	Check emulsion appearance	Disperser	Test panel
		Test the feel on application	Homogenizer	Technicians
		Check emulsion stability	Viscometer
		Modify prototype formula	pH meter
			Particle size distribution analyzer
4.4.3 Test product performance	Prototype cream formula	Check antioxidant effect	Solar simulator	Formulators	9b	Prototype formula with refined concentration of active ingredients
	Heuristics for formula modification	Check SPF value	Animal model	Scientists
		Check moisturizing effect	Bioassay	Test panel
		Fine tune concentration of active ingredients	Skin analyzer	Technicians

^aThe total duration was calculated by assuming 20 inner loop iterations in the workflow of prototype fabrication (Fig. 8), and each loop took an average time of 1 week.

^bThe total duration was calculated by assuming 3 outer loop iterations in the workflow of prototype fabrication (Fig. 8), and each loop took an average time of 3 weeks.