3,6-Dimethyl-1,4-dioxane-2,5-dione homopolymer

Chemical properties

Poly(DL-lactic acid) is a glassy material, occurring as white to golden-yellow pellets or granules.

The Uses of 3,6-Dimethyl-1,4-dioxane-2,5-dione homopolymer

Controlled release

The Uses of 3,6-Dimethyl-1,4-dioxane-2,5-dione homopolymer

May be used to make drug delivery materials for controlled release.

Production Methods

Lactic acid is a chiral molecule and has two optically active forms: Llactic acid and D-lactic acid. Poly(DL-lactic acid) is produced from the racemic mixture of lactic acid. Lactic acid is produced either from ethylene (petrochemical pathway) or by bacterial fermentation of D-glucose derived from food stocks. The former pathway involves an oxidation step followed by treatment with hydrogen cyanide and produces only racemic DL-lactic acid. In contrast, lactic acid produced by fermentation occurs mainly as L-lactic acid. Lowmolecular- weight poly-DL-(lactic acid) (500–10 000 Da) is produced directly from lactic acid by condensation. Higher-molecular-weight product is produced by one of two major pathways. The first involves a depolymerization of low-molecular-weight polymer into the cyclic dimer form (lactide) followed by ring-opening polymerization. Alternatively, it can be produced by a direct condensation using azeotropic distillation.

Definition

ChEBI: Lactide is a member of dioxanes.

General Description

Resomer^? R 207 S, Poly(D,L-lactide) (PDLLA), a biodegradable and biocompatible polymer, can be used for a variety of biological applications. It shows properties like long degradation time, mechanical stiffness and hydrophobicity.

Pharmaceutical Applications

Poly(DL-lactic acid) is used in drug delivery systems in implants, injections, and oral solid dispersions. It is also used as a coating agent.

Safety

Poly(DL-lactic acid) degrades to produce lactic acid, which is considered a well-tolerated nontoxic material. Several in vitro and in vivo studies demonstrated that poly(lactic acid) in general (including poly(DL-lactic acid)) is well tolerated and does not induce a significant immune response.However, some studies have illustrated signs of a mild immune response.The FDA has also reported some rare cases of inflammatory responses in patients treated with cosmetic poly(DL-lactic acid) injections.

Storage

Poly(DL-lactic acid) is stable under dry conditions. However, it typically biodegrades over a period of 10–15 months according to the molecular weight. Increasing moisture and temperature enhances biodegradation; the onset of degradation in water at 25°C is 6 months.In contrast to many other biodegradable polymers, poly(DL-lactic acid) degrades through a two-step mechanism. The primary degradation step involves the hydrolysis of the ester bonds independently of microbial activity to produce a low-molecular-weight polymer. When the molecular weight drops below 10 000, microorganisms digest the polymer into carbon dioxide and water. Poly(DL-lactic acid) is more stable than poly(L-lactic acid) or poly(D-lactic acid) alone.Poly(DL-lactic acid) should be stored in a dry inert environment at a temperature of －15°C to －20°C.

Incompatibilities

Incompatible with strong acids or alkaline materials.

Regulatory Status

Included in the FDA Inactive Ingredients Database (IM, powder, for injection, suspension, and lyophilization). Poly(DL-lactic acid) is considered as ‘not hazardous’ according to the European Directive 67/548/EEC. Included in parenteral preparations (prolongedrelease powder for suspension for subcutaneous or intramuscular injection) licensed in the UK.