Methacrylic Acid and Ethyl Acrylate Copolymer (1:1)

Methacrylic acid-ethyl acrylate copolymer (1:1) – (anionic copolymer, acrylic polymer)

Synonyms: methacrylic acid–ethyl acrylate copolymer, ethyl acrylate–methacrylic acid copolymer, “methacrylic acid copolymer (type B/C)” (pharmaceutical context)
INCI / functions: film former, viscosity control (in specific systems), binder; pharmaceutical use: polymer for enteric coatings

Definition

An anionic copolymer from the acrylic family, composed of repeating units primarily derived from methacrylic acid and ethyl acrylate, typically in a 1:1 ratio. In compositional terms, the ingredient is therefore a polymer built from these two monomeric units (with possible trace residual monomers and polymerization auxiliaries depending on grade). The presence of carboxylic groups (from methacrylic acid) confers marked pH sensitivity: the film is poorly soluble in acidic media and tends to dissolve/swell when pH exceeds a threshold (indicatively > 5.5), a property mainly exploited for enteric protection and targeted release.

Calories (energy value)

Identification data and specifications

Functional role and clarification “film former / pH-sensitive”

Formulation compatibility

Use guidelines (indicative)

Typical applications

• Pharmaceutical: enteric coatings for tablets, pellets, and capsules; protection of acid-sensitive APIs and reduction of gastric irritation; targeted release at intestinal pH.

• Technical: pH-dependent film-forming systems where a barrier in acid and opening at higher pH is desired (case-by-case evaluation depending on grade).

Quality, grades and specifications

Note: in pharma, “type” grades (e.g., Type B) and supply forms as powder or aqueous dispersion are common; selection affects both process and coating outcome.

Safety, regulation and environment

Formulation troubleshooting

Conclusion

Methacrylic acid-ethyl acrylate copolymer is a pH-sensitive acrylic film former, mainly composed of methacrylic acid and ethyl acrylate units (typically 1:1). Its key technical value is the ability to provide a film that remains stable in acidic conditions and becomes more soluble above a pH threshold (order of > 5.5), making it a reference polymer for enteric protection and targeted release. Performance depends primarily on pH, film weight/thickness, plasticization, and process conditions; validation on the real dosage form is essential.

Studies

The need to use neutral methacrylate copolymer and anionic methacrylate copolymer in solid food supplements is dictated by technological reasons. Neutral methacrylate copolymer is intended to be used as a sustained-release coating agent. Sustained-release formulations allow the continuous dissolution of a nutrient over a period of time. Anionic methacrylate copolymer is intended to be used as a coating agent to protect the stomach wall from irritating ingredients and/or to protect sensitive nutrients from disintegration by gastric acid. (1).

In the European Food Additives List, neutral methacrylate copolymer has been assigned the number E 1206 and anionic methacrylate copolymer E 1207.

In this study, the effect that minor to moderate polymer degradation within the extrudates has on their long-term physical stability and dissolution characteristics is analyzed and discussed (2).

The intention of this study was to show under what conditions a film-forming methacrylic acid copolymer coating excipient, corresponding to pharmacopoeia requirements but obtained from different sources, can be replaced without serious problems (3).

Some studies on microencapsulation and active ingredient release techniques involving methacrylic acid-ethyl acrylate copolymer (4).

It appears as a white powder with a boiling point of 73-74 °C (pressure: 0.2 Torr).

Density: 1.168±0.06 g/cm3

PH:  2.1-3.0

Methacrylic Acid and Ethyl Acrylate Copolymer studies

Molecular Formula:  C₉H₁₄O₄

Molecular Weight:  186.20

CAS: 25212-88-8

NACRES:  NA.24

Synonyms:

• Ethylacrylat-Methacrylsure-Copolymer
• Eudragit^®

References____________________________________________________________________

(1) POOL/E3/2012/12756 European Commission

(2) Mathers A, Hassouna F, Malinová L, Merna J, Růžička K, Fulem M. Impact of Hot-Melt Extrusion Processing Conditions on Physicochemical Properties of Amorphous Solid Dispersions Containing Thermally Labile Acrylic Copolymer. J Pharm Sci. 2020 Feb;109(2):1008-1019. doi: 10.1016/j.xphs.2019.10.005.

(3) Binder V, Hirsch S, Scheiffele S, Bauer KH. Preliminary applicability tests of different methacrylic acid copolymers, type C NF, particularly relevant to spreading and film formation. Eur J Pharm Biopharm. 1998 Sep;46(2):229-32. doi: 10.1016/s0939-6411(97)00163-x. 

Abstract. The intention of this study was to show under which conditions a film forming methacrylic acid copolymer coating excipient, corresponding to the requirements of pharmacopoeia, but obtained from different sources, can be substituted without severe problems. The mechanical properties of the film coats were investigated by dynamic-mechanical thermo-analysis (DMTA) experiments to determine with respect to the glass transition the storage modulus E', the loss modulus E'', and the loss factor tan delta. Further determinations concerned the surface tensions of the different coating dispersions. This attribute plays an important role in spreading, distribution and coalescence of the film forming preparations. Finally by a series of small experimental fluidized bed batches cores containing a model drug were coated with the different methacrylic acid copolymers. The resistance of these coated tablets in 0.1 N HC1 as well as their dissolution rates in artificial intestinal juice were tested. The coatings proved themselves so similar that in this case substitutions of products of different provenance are possible. The determinations of surface tension and the DMTA measurements seem to be useful and reliable preliminary applicability tests.

(4) Homayun B, Sun C, Kumar A, Montemagno C, Choi HJ. Facile fabrication of microparticles with pH-responsive macropores for small intestine targeted drug formulation. Eur J Pharm Biopharm. 2018 Jul;128:316-326. doi: 10.1016/j.ejpb.2018.05.014. 

Fleer NA, Pelcher KE, Zou J, Nieto K, Douglas LD, Sellers DG, Banerjee S. Hybrid Nanocomposite Films Comprising Dispersed VO2 Nanocrystals: A Scalable Aqueous-Phase Route to Thermochromic Fenestration. ACS Appl Mater Interfaces. 2017 Nov 8;9(44):38887-38900. doi: 10.1021/acsami.7b09779.

Abstract. Buildings consume an inordinate amount of energy, accounting for 30-40% of worldwide energy consumption. A major portion of solar radiation is transmitted directly to building interiors through windows, skylights, and glazed doors where the resulting solar heat gain necessitates increased use of air conditioning. Current technologies aimed at addressing this problem suffer from major drawbacks, including a reduction in the transmission of visible light, thereby resulting in increased use of artificial lighting. Since currently used coatings are temperature-invariant in terms of their solar heat gain modulation, they are unable to offset cold-weather heating costs that would otherwise have resulted from solar heat gain. There is considerable interest in the development of plastic fenestration elements that can dynamically modulate solar heat gain based on the external climate and are retrofittable onto existing structures. The metal-insulator transition of VO2 is accompanied by a pronounced modulation of near-infrared transmittance as a function of temperature and can potentially be harnessed for this purpose. Here, we demonstrate that a nanocomposite thin film embedded with well dispersed sub-100-nm diameter VO2 nanocrystals exhibits a combination of high visible light transmittance, effective near-infrared suppression, and onset of NIR modulation at wavelengths <800 nm. In our approach, hydrothermally grown VO2 nanocrystals with <100 nm diameters are dispersed within a methacrylic acid/ethyl acrylate copolymer after either (i) grafting of silanes to constitute an amorphous SiO2 shell or (ii) surface functionalization with perfluorinated silanes and the use of a perfluorooctanesulfonate surfactant. Homogeneous and high optical quality thin films are cast from aqueous dispersions of the pH-sensitive nanocomposites onto glass. An entirely aqueous-phase process for preparation of nanocrystals and their effective dispersion within polymeric nanocomposites allows for realization of scalable and viable plastic fenestration elements.