Lithium salt extended-release formulations; methods of making; and methods of use thereof

An extended-release, bilayer oral tablet, comprising:

• a.) a first layer comprising an extended-release polymer matrix portion comprising
• about 70 to about 80 wt % lithium carbonate,
• about 10 to about 20 wt % of a hydroxypropyl methyl cellulose, polyvinylpyrrolidone,
• microcrystalline cellulose, and
• a glidant, a lubricant, or a glidant and a lubricant,
• wherein the weight percents of lithium carbonate and hydroxypropyl methyl cellulose are based on the total weight of the extended-release polymer matrix portion;
• b.) a second layer comprising a gastroretentive portion comprising about 75 to about 85 wt % of a swellable polymer based on the total weight of the gastroretentive portion, wherein the swellable polymer is a high molecular weight polyethylene oxide having a molecular weight of 100,000 grams per mole or greater,
• a hydroxypropyl methyl cellulose, and
• a lubricant, a colorant, or a lubricant and a colorant;
• and
• c.) a film coating;
• wherein the tablet contains about 600 mg lithium carbonate per tablet and a weight ratio of the extended-release polymer matrix portion to the gastroretentive portion is about 2.5:1 to about 1.5:1;
• or
• wherein the tablet contains about 900 mg lithium carbonate per tablet and a weight ratio of the extended-release polymer matrix portion to the gastroretentive portion is about 3.5:1 to about 2.5:1.