Pharmaceutical compositions containing lithium carbonate - Patent 6989159 Once daily pharmaceutical compositions containing lithium carbonate in the form of coated granules. 424/491, 424/492, 424/458, 424/480, 424/496, 514/951, 424/495, 424/468, 514/964, 424/494, 424/457, 424/497, 424/461, 424/490, 424/493, 424/462 The use of lithium salts in the treatment of depressive and manic disorders, psychosis, some types of cephalalgia, has been known for many years. One of the major drawbacks related with lithium therapy is its low therapeutic index on the one hand, and the need to ensure constant therapeutically useful concentrations, below the toxicity levels, on the other. An appropriate therapeutical regimen can be obtained with the preparations commercially available at present, carrying out two to three daily administrations. Lithium carbonate is completely absorbed in the gastrointestinal tract in about 8 hours, the plasma concentration peak being between, 2 and 4 hours. After being absorbed, the cation is slowly distributed inside the cells of different organs and its distribution volume approaches 1 (0.7–0.9), reaching the steady state at a concentration in the liquor below 50% compared with the plasmatic one. The starting half-life, after the first administration, is reduced by the redistribution. The plasma half-life at the steady state is 20–24 hours. More than 95% of lithium is eliminated through urine; like sodium, 80% thereof is reabsorbed in the proximal convoluted tubule and has clearance corresponding to about 20% of that of the creatinine. The lower the peak lithium concentration in the plasma, the steadier its elimination. It is therefore desirable to have controlled release formulations to decrease the number of daily administrations and the value of the plasma peaks, thus avoiding to attain toxic concentrations while increasing the patient compliance.
