Lonza Rockland Inc., Rockland, ME, is promoting a product called SeaPure Agarose (INCI: Agarose) for use in cosmetics. Agarose is a neutral gelling polymer derived from red seaweed (Rhodophyta). A study published in Tissue Engineering (Volume 11, 2005) used an injectable agarose-based delivery system on rodent skin which invoked a wound-healing response through day 14. It was suggested that tissue engineering and wound-healing applications may benefit from this treatment.

Agarose has been used as nanoparticles to administer therapeutic proteins and peptides. Agarose hydrogel is formed when cooled below the gelling temperature (31-36°C) and provides a matrix for the proteins to be entrapped in the gel during formation. Rice University scientists have recently used microsponges consisting of 280 micrometer beads of agarose as a diagnostic tool to detect heart disease, cancers, HIV and other diseases quickly due to its ability to capture biomarkers (molecules that furnish information about a person’s health that are found in blood, saliva, and other body fluids).

Following is a list of agarose characteristics:

• Natural polysaccharide with a low percentage of residual charged groups;

• Compatible with almost all ingredients including highly anionic or cationic materials, even at high concentration;

• No salts, counterions, pH changes, other polymers or initiators needed for gelation. Functions in low pH situations;

• Easy incorporation and release of active ingredients;

• Strong gels at low concentrations;

• Forms thermoreversible gels: gels from 28°C to 42°C, and remelts at 65°C to 100°C, depending upon grade;

• Reduces need for other ingredients to obtain desired rheology and skin feel;

• Clear and odorless, will accept color or fragrance additives;

• Non-greasy thickener with good rub-out and minimal residue smooth, clean skin feel; and

• Compatible with citric, lactic, and glycolic acid, triethanolamine and sodium hydroxide, and all surfactant types.

When preparing agarose in a laboratory, the procedure below is followed.

Put distilled water in a beaker, which is 2-4 times the volume of the solution. Disperse agarose into water with constant agitation. Prevent lump formation.

Heat agarose slurry in a hot water bath to a minimum of 80°C and hold until solution is clear. Add water to compensate for evaporation loss. Cool to 60-70°C with slow stirring before incorporation of other ingredients.

If preparing formed gels, pour into molds and allow to gel at room temperature. If using as a thickener, continue stirring as solution cools to prevent gel formation during the cooling phase. Other gums, such as CMC or xanthan, may be dry blended with agarose before dispersing in water. If 5-10% glycerin is used in the formulation, it may be blended with the dry agarose before dispersing in water.

A Delivery System

In cosmetics, SeaPure Agarose is suggested as a delivery system for the release of water-based actives or additives in lotions, sprays, sticks, gels or encapsulated formats.
An example of an agarose gel follows:

After Sun Cooling Gel

Ingredients:	%WT
Phase A
Propylene glycol	3.00
Methyl paraben	0.20
Ethyl paraben	0.05
Glycerin	10.00
Alcohol	10.00
Phase B
Aloe vera leaf extract	0.50
Water	23.25
Phase C
SeaPure Agarose	3.00
Water	50.00

Procedure: Prepare molds. Mix A ingredients together. Warm B ingredients to 40-50°C. Disperse agarose in warm water with agitation, heat to boiling and cool to 75°C. Add B to C with good agitation, add A. Pour into molds and cool at room temperature until gels set. Do not cool below 50°C. Package in moisture proof, airtight containers.


Harvey Fishman has a consulting firm located at 34 Chicasaw Drive, Oakland, NJ 07436, [email protected], specializing in cosmetic formulations and new product ideas, offering tested finished products. He has more than 30 years of experience and has been director of research at Bonat, Nestlé LeMur and Turner Hall. He welcomes descriptive literature from suppliers and bench chemists and others in the field.