Extended release pharmaceutical formulations with controlled impurity levels

An extended release pharmaceutical formulation, comprising:

• a gastroretentive core comprising
• (a) a therapeutically effective amount of valsartan of about 160 mg;
• (b1) alpha tocopherol polyethylene glycol succinate in an amount of about 80 mg;
• (b2) polyoxyethylene polyoxypropylene block copolymer in an amount of about 80 mg;
• (c) hydroxypropyl methylcellulose in an amount of not less than about 200 mg;
• a dual coating system surrounding the gastroretentive core;
• wherein the formulation comprises not more than about 0.7% by weight of valsartan R-isomer impurity;
• wherein a process of solubilization of valsartan is carried out at a temperature between 60° and 70° C.;
• wherein valsartan is completely or partially solubilized with (b1) and (b2);
• and
• wherein the dual coating system comprises a seal coating layer contacting the gastroretentive core.