The administration of levoleucovorin is useful as an antidote to drugs which act as folic acid antagonists and in combination chemotherapy with 5-FU. The most often used calcium salt of levoleucovorin has a limited solubility in water and forms almost insoluble degradation products. Therefore aqueous solutions are unstable and precipitates are resulting. Precipitates in injectable products present an unacceptable safety risk to patients. Stable high strength pharmaceutical aqueous compositions containing calcium salts, magnesium or zinc salts of levoleucovorin and one or more of the compounds sodium gluconate, potassium gluconate, glycerophosphate disodium salt or glycerophosphate dipotassium salt are disclosed.
