| Chemical Properties | Propylene glycol alginate is practically odorless and tasteless. The propylene glycol ester of alginic acid varies in composition according to its degree of esterification and the percentages of free and neutralized carboxyl groups in the molecule. For a detailed description of this compound refer to Burdock (1997). |
| Chemical Properties | Propylene glycol alginate occurs as a white to yellowish colored, practically odorless and tasteless, fibrous or granular powder. |
| Uses | Propylene Glycol Alginate is a gum that is the propylene glycol ester of alginic acid, which is obtained from kelp. as compared to sodium alginates, it has reduced sensitivity to acid and calcium salts. it functions in acidic systems. it functions as a thickener, stabilizer, and emulsifier in beer, salad dressings, syrups, and fruit drinks. |
| Uses | Pharmaceutic aid (suspending agent); pharmaceutic aid (viscosity-increasing agent). |
| Preparation | Derived from brown algae, also from alginic acid |
| Production Methods | Alginic acid, extracted from brown seaweed, is reacted with propylene oxide to form propylene glycol alginate. Various grades may be obtained that differ in composition according to the degree of esterification and the percentage of free and neutralized carboxyl groups present in the molecule; complete esterification of alginic acid is impractical. |
| Pharmaceutical Applications | Propylene glycol alginate is used as a stabilizing, suspending, gelling, and emulsifying agent in oral and topical pharmaceutical formulations. Typically, a concentration of 0.3–5% w/v is used, although this may vary depending upon the specific application and the grade of propylene glycol alginate used.
Propylene glycol alginate is also used in cosmetics and food products. |
| Safety Profile | Mddly toxic by ingestion. When heated to decomposition it emits acrid smoke and irritating fumes. |
| Safety | Propylene glycol alginate is used in oral and topical pharmaceutical formulations, cosmetics, and food products. It is generally regarded as a nontoxic and nonirritant material, although excessive oral consumption may be harmful. A study in five healthy male volunteers fed a daily intake of 175 mg/kg body-weight of propylene glycol alginate for 7 days, followed by a daily intake of 200 mg/kg body-weight of propylene glycol alginate for a further 16 days, showed no significant adverse effects.
Inhalation of alginate dust may be irritant and has been associated with industrially related asthma in workers involved in alginate production. However, it appears that the cases of asthma were linked to exposure to seaweed dust rather than pure alginate dust.
(hamster, oral): 7.0 g/kg
(mouse, oral): 7.8 g/kg
(rabbit, oral): 7.6 g/kg
(rat, oral): 7.2 g/kg |
| storage | Propylene glycol alginate is a stable material, although it will gradually become less soluble if stored at elevated temperatures for extended periods.
Propylene glycol alginate solutions are most stable at pH 3–6. In alkaline solutions, propylene glycol alginate is rapidly saponified. Alginate solutions are susceptible to microbial spoilage and should be sterilized or preserved with an antimicrobial preservative. However, sterilization processes may adversely affect the viscosity of propylene glycol alginate solutions; see Sodium Alginate.
The bulk material should be stored in an airtight container in a cool, dry place. |
| Regulatory Status | GRAS listed. Accepted in Europe for use as a food additive. Included in the FDA Inactive Ingredients Database (oral preparations). Included in nonparenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients. |