A method for improving the solubility of a dry powder cell culture medium by a) identifying the one or more poorly soluble components in the said cell culture medium selected from the group of cystine, iron citrate hydrate, iron chloride hexahydrate and/or tyrosine b) co-lyophilizing the components identified in step a) with at least one other component of said cell culture medium as a carrier component c) preparing the said dry powder cell culture medium by mixing the one or more co-lyophilisates generated in step b) with the other components of the cell culture medium and optionally milling the resulting mixture, whereby the one or more carrier components are selected from the following group: - Calcium Chloride, anhydrous and hydrated forms - Di-Potassium hydrogen phosphate, anhydrous and hydrated forms - Di-Sodium hydrogen phosphate, anhydrous and hydrated forms - Magnesium chloride, anhydrous and hydrated forms - Magnesium sulfate, anhydrous and hydrated forms - Potassium chloride - Potassium dihydrogen phosphate - Sodium Chloride - Sodium dihydrogen phosphate, anhydrous and hydrate forms - Sodium hydrogen carbonate - D(-)-Fructose - D(-)-Mannitol - D(+)-Galactose - D(+)-Glucose, anhydrous and hydrate forms - D(+)-Mannose - Glycine - Glycyl-L-tyrosine Hydrate - L-alanine - L-Alanyl-L-Glutamine - L-Arginine and hydrochloride forms - L-Asparagine monohydrate - L-Aspartic Acid - L-Cysteine and Hydrochloride/Hydrate forms - L-Glutamic acid - L-Glutamine - L-Histidine and hydrochloride forms - L-Hydroxyproline - L-Isoleucine - L-Leucine - L-Lysine Monohydrate and hydrochloride forms - L-Methionine - L-Phenylalanine - L-Proline - L-Serine - L-Threonine - L-Tryptophan - L-Valine - Mono-sodium-L-aspartate-monohydrate - Phospho-Tyrosine Di-Sodium Salt - Sodium L-glutamate monohydrate - HEPES_CCM - HEPES Sodium - MOPS - Choline Chloride - Poloxamer 188 - Sodium acetate trihydrate - myo-Inositol - Oxalacetic acid - Succinic Acid - Pyruvic Acid Sodium Salt - alpha-Ketoglutaric Acid Disodiumsalt Dihydrate - beta-Glycerophosphoric acid disodium salt pentahydrate or mixtures thereof a) identifying the one or more poorly soluble components in the said cell culture medium selected from the group of cystine, iron citrate hydrate, iron chloride hexahydrate and/or tyrosine b) co-lyophilizing the components identified in step a) with at least one other component of said cell culture medium as a carrier component c) preparing the said dry powder cell culture medium by mixing the one or more co-lyophilisates generated in step b) with the other components of the cell culture medium and optionally milling the resulting mixture, - Calcium Chloride, anhydrous and hydrated forms - Di-Potassium hydrogen phosphate, anhydrous and hydrated forms - Di-Sodium hydrogen phosphate, anhydrous and hydrated forms - Magnesium chloride, anhydrous and hydrated forms - Magnesium sulfate, anhydrous and hydrated forms - Potassium chloride - Potassium dihydrogen phosphate - Sodium Chloride - Sodium dihydrogen phosphate, anhydrous and hydrate forms - Sodium hydrogen carbonate - D(-)-Fructose - D(-)-Mannitol - D(+)-Galactose - D(+)-Glucose, anhydrous and hydrate forms - D(+)-Mannose - Glycine - Glycyl-L-tyrosine Hydrate - L-alanine - L-Alanyl-L-Glutamine - L-Arginine and hydrochloride forms - L-Asparagine monohydrate - L-Aspartic Acid - L-Cysteine and Hydrochloride/Hydrate forms - L-Glutamic acid - L-Glutamine - L-Histidine and hydrochloride forms - L-Hydroxyproline - L-Isoleucine - L-Leucine - L-Lysine Monohydrate and hydrochloride forms - L-Methionine - L-Phenylalanine - L-Proline - L-Serine - L-Threonine - L-Tryptophan - L-Valine - Mono-sodium-L-aspartate-monohydrate - Phospho-Tyrosine Di-Sodium Salt - Sodium L-glutamate monohydrate - HEPES_CCM - HEPES Sodium - MOPS - Choline Chloride - Poloxamer 188 - Sodium acetate trihydrate - myo-Inositol - Oxalacetic acid - Succinic Acid - Pyruvic Acid Sodium Salt - alpha-Ketoglutaric Acid Disodiumsalt Dihydrate - beta-Glycerophosphoric acid disodium salt pentahydrate