Controlled release solid dosage forms of lithium carbonate - Patent 6365196 A process for preparing controlled release solid dosage forms of lithium carbonate by using a dissolution rate stabilizer and a hydrophobic waxy material. 1. A process for preparing controlled release solid dosage forms of lithium carbonate which comprises the steps of: (a) blending lithium carbonate, a hydrophobic waxy material, a dissolution rate stabilizer and optional pharmaceutical excipients; and (b) formulating the resulting blend into solid dosage forms. Lithium carbonate is indicated in the treatment of manic episodes of manic-depressive illness and is commercially available in controlled release tablets under the tradename Eskalith CR®. In addition to the active ingredient—lithium carbonate, approx. 91%,—Eskalith CR® tablets contain alginic acid, 1%, gelatin, 4%, sodium starch glycolate, approx. 4%, iron oxide, trace amount, and magnesium stearate, 1%, as inactive ingredients. Eskalith CR® tablets have been manufactured for a number of years by a high shear wet granulation process that is characterized by a significant time dependent retardation in the dissolution rate of lithium carbonate which results in a shortened shelf-life for the product. Furthermore, significant batch to batch variability in the release rates of the active ingredient, both initially and on storage, is a persistent problem with the current process/product. The batch to batch variability in the release rate of lithium carbonate is of particular concern to the therapeutic use of this agent because lithium toxicity is closely related to serum lithium levels, and can occur at doses close to therapeutic levels. Lithium toxicity is so much of a concern that it is recommended that facilities for prompt and accurate serum lithium determinations be available before initiating therapy with lithium carbonate.
EQUATION FOR LITHIUM CARBONATE
lithium carbonate molecular
