Polymer mixture with resistance against the influence of ethanol

PREFERRED EMBODIMENT

[0088]In a preferred embodiment the polymer mixture may be a mixture from a

[0089]polymer 1, polymerized from a monomer mixture consisting of the monomers

[0090](a1) 70 to 95, preferably 85 to 95% by weight of 2-ethylhexyl methacrylate and 2-ethyl methacrylate at a ratio of from 3:1 to 1:1.

[0091](b1) 5 to 30, preferably 5-15% by weight of 2-trimethylammonium-ethyl-methacrylate-chloride and a polymer 2, polymerized from a monomer mixture consisting of the monomers

[0092](a2) 70 to 95, preferably 85 to 95% by weight of 2-ethylhexyl methacrylate and 2-ethyl methacrylate at a ratio from 3:1 to 1:1.

[0093](c2) 5-30, preferably 5-15% by weight of 2-hydroxyethyl methacrylate, wherein the polymer mixture is comprising polymer 1 to polymer 2 at a ratio by weight of from 2:1 to 1:2, and wherein polymer 1 to polymer 2 add up to 100%.

[0094]Preferably, the polymers 1 and / or 2 of the preferred embodiment may have one, two or three of the following properties in any possible combina

Polymerization

[0246]Table 1 summarizes the compositions of polymers 1 and 2 (according to the invention) and commercially available polymers EUDRAGIrRL, EUDRAGIT® RS and EUDRAGIT® NM (comparative, not according to the invention) with sustained release characteristics.

[0247]Abbreviations in table 1: (%=% by weight, Da=Dalton, Mw=weight-average molecular weight, Tmg=midpoint glass transition temperature, MFFT=minimum film forming temperature, D=Dispersity Index)

[0248]Procedure is described exemplarily for Polymer 1 (see Table 1). Polymer 2 was manufactured in the same manner. Setup consisted of a 1 L reaction vessel equipped with lid, agitator, condenser, nitrogen inlet and thermal sensor. Heating was carried out by a thermostat controlled water bath. A dosage pump with silicone tubes was used to dose monomer emulsion into the reaction mixture. In a first step, 534.0 g of water and 6.6 g of sodium dodecyl sulfate (SDS 15, 15.0% (w / w) aqueous solution) were dosed into the reactor, purge

f Polymer Dispersion on Metoprolol Succinate Pellets

[0251]Metoplolol Succinate pellets were obtained from Lee Pharma Limited (Telangana, India). Drug content is 40%. Particle size (determined by sieve analysis) is specified as follows: not more than 10% retains on sieve #16 ASTM and not more than 10% passes through sieve #25 ASTM (this relates to ca. 1 mm mean pellet diameter).

[0252]Dispersions of Polymer 1 and Polymer 2 (30% (w / w) polymer solid content) from Example 1 were used as is, or mixed in ratio 1:1.36 g talc (100% (w / w) compared to dry polymer mass) were suspended in 204 g water and homogenized using ultra turrax for 15 minutes. Subsequently, the prepared suspension was mixed with 120 g polymer dispersion (or dispersion mixture) and stirred for one hour. The amount of water for suspension of talc was calculated to result in a final spraying suspension of 20% (w / w) solid content. Coating experiments were carried out on a Huttlin (Schopfheim, Germany) Mycrolab (H00263), eq