Poloxamer 237

Category

Dispersant; Emulsifier; Solubilizer; Lubricant; Humectant

Molecular Formula

HO(C2H4O)a(C3H6O)b(C2H4O)aH

Molecular Weight

6 840-8 830

Grade

Pharmceutical Excipients

Description

Poloxamers generally occur as white, waxy, free-flowing prilled granules, or as cast solids. They are practically odorless and tasteless.

UNII

NA

Chemical Name

a-Hydro-o-hydroxypoly(oxyethylene)poly(oxypropylene) poly-(oxyethylene) block copolymer

CAS Number

9003-11-6

Synonyms

Lutrol; Monolan; Pluronic; poloxalkol; poloxamera; polyethylene-propylene glycol copolymer; polyoxyethylene-polyoxypropylene copolymer; Supronic; Synperonic

Administration route

Topical administration.

Dosage Form

IV injections; inhalations, ophthalmic preparations; oral powders, solutions, suspensions, and syrups; topical preparations

Stability and Storage Conditions

Poloxamers are stable materials. Aqueous solutions are stable in the presence of acids, alkalis, and metal ions. However, aqueous solutions support mold growth. The bulk material should be stored in a well-closed container in a cool, dry place.

Source and Preparation

Poloxamer polymers are prepared by reacting propylene oxide with propylene glycol to form polyoxypropylene glycol. Ethylene oxide is then added to form the block copolymer.

Applications

Poloxamers are nonionic polyoxyethylene-polyoxypropylene polymers used primarily in pharmaceutical formulations as emulsifying or solubilizing agents. The polyoxyethylene segment is hydrophilic while the polyoxypropylene segment is hydrophobic. All of the poloxamers are chemically similar in composition, differing only in the relative amounts of propylene and ethylene oxides added during manufacture. Their physical and surface-active properties vary over a wide range and a number of different types are commercially available. Poloxamers are used as emulsifying agents in intravenous fat emulsions, and as solubilizing and stabilizing agents to maintain the clarity of elixirs and syrups. Poloxamers may also be used as wetting agents; in ointments, suppository bases, and gels; and as tablet binders and coatings. Poloxamer 188 has also been used as an emulsifying agent for fluorocarbons used as artificial blood substitutes, and in the preparation of solid-dispersion systems. More recently, poloxamers have found use in drug-delivery systems.Therapeutically, poloxamer 188 is administered orally as a wetting agent and stool lubricant in the treatment of constipation; it is usually used in combination with a laxative such as danthron. Poloxamers may also be used therapeutically as wetting agents in eye-drop formulations, in the treatment of kidney stones, and as skin-wound cleansers.

Safety

Poloxamers are used in a variety of oral, parenteral, and topical pharmaceutical formulations, and are generally regarded as nontoxic and nonirritant materials. Poloxamers are not metabolized in the body. Animal toxicity studies, with dogs and rabbits, have shown poloxamers to be nonirritating and nonsensitizing when applied in 5% w/v and 10% w/v concentration to the eyes, gums, and skin. In a 14-day study of intravenous administration at concentrations up to 0.5 g/kg/day to rabbits, no overt adverse effects were noted. A similar study with dogs also showed no adverse effects at dosage levels up to 0.5 g/kg/day. In a longer-term study, rats fed 3% w/w or 5% w/w of poloxamer in food for up to 2 years did not exhibit any significant symptoms of toxicity. However, rats receiving 7.5% w/w of poloxamer in their diet showed some decrease in growth rate. No hemolysis of human blood cells was observed over 18 hours at 25℃, with 0.001-10% w/v poloxamer solutions. Acute animal toxicity data for poloxamer 188: LD50 (mouse, IV): 1 g/kg LD50 (mouse, oral): 15 g/kg LD50 (mouse, SC): 5.5 g/kg LD50 (rat, IV): 7.5 g/kg LD50 (rat, oral): 9.4 g/kg

Incompatibilities

Depending on the relative concentrations, poloxamer 191 is incompatible with phenols and parabens.