Polymethacrylates

Synonyms: Acryl-EZE; acidi methacrylici et ethylis acrylatis polymerisatum; acidi methacrylici et methylis methacrylatis polymerisatum; ammonio methacrylatis copolymerum; copolymerum methacrylatis butylati basicum; Eastacryl; Eudragit; Kollicoat MAE; polyacrylatis dispersio 30 per centum; polymeric methacrylates.

Description:

Polymethacrylates are synthetic cationic and anionic polymers of dimethylaminoethyl methacrylates, methacrylic acid, and methacrylic acid esters in varying ratios. Several different types are commercially available and may be obtained as the dry powder, as an aqueous dispersion, or as an organic solution. A (60 : 40) mixture of acetone and propan-2-ol is most commonly used as the organic solvent.

Film-forming agent; tablet binder; tablet diluent.

• Polymethacrylates are primarily used in oral capsule and tablet formulations as film-coating agents.

• Depending on the type of polymer used, films of different solubility characteristics can be produced.

• Eudragit E is used as a plain or insulating film former.

• It is soluble in gastric fluid below pH 5.

• In contrast, Eudragit L, S and FS types are used as enteric coating agents because they are resistant to gastric fluid.

• Different types of enteric coatings are soluble at different pH values: e.g. Eudragit L is soluble at pH > 6 whereas Eudragit S and FS are soluble at pH > 7.

• The S grade is generally used for coating tablets, while the flexible FS 30 D dispersion is preferred for coating particles.

• Eudragit RL, RS, NE 30 D, NE 40 D, and NM 30 D are used to form water-insoluble film coats for sustained-release products. Eudragit RL films are more permeable than those of Eudragit RS, and films of varying permeability can be obtained by mixing the two types together.

• The neutral Eudragit NE/NM grades do not have functional ionic groups. They swell in aqueous media independently of pH without dissolving.

Incompatibilities occur with certain polymethacrylate dispersions depending upon the ionic and physical properties of the polymer and solvent. For example, coagulation may be caused by soluble electrolytes, pH changes, some organic solvents, and extremes of temperature

For example, dispersions of Eudragit L 30 D, RL 30 D, L 100-55, and RS 30 D are incompatible with magnesium stearate. Eastacryl 30 D, Kollicoat MAE 100 P, and Kollicoat MAE 30 DP are also incompatible with magnesium stearate.

Polymethacrylate copolymers are widely used as film-coating materials in oral pharmaceutical formulations. They are also used in topical formulations and are generally regarded as nontoxic and nonirritant materials.

Observe normal precautions appropriate to the circumstances and quantity of material handled. Additional measures should be taken when handling organic solutions of polymethacrylates. Eye protection, gloves, and a dust mask or respirator are recommended. Polymethacrylates should be handled in a well-ventilated environment and measures should be taken to prevent dust formation.

Methyl methacrylate; poly(methyl methacrylate).