in the following table 1 , the calculated ratio of surface area to volume ( a / v ) is shown by way of example for containers of various nominal capacities v , the nominal capacity or volume v being defined as the total volume of the gemcitabine solution and a as the calculated surface area of the glass container wetted by the gemcitabine solution . in table 2 , the calculated ratio of the surface area to the capacity ( at / rv ) is shown by way of example for containers of nominal capacity rv , the capacity rv being defined as the full - to - the - edge capacity of the glass container and at as the calculated surface area of the glass container . the percentage of residual content of active ingredient in the gemcitabine preparation at the end of the running time which results from a decomposition of the active ingredient in during storage is limited to 95 % of the initial content by registration guidelines of the drug authorities . in this connection and in the following stability investigations , the term “ stability of the solution ” is to be understood to be the stability of the gemcitabine solution , that is , as the long - term consistency of the concentration of the starting compound after it is brought into solution . the stability investigations of ready - to - use solutions containing gemcitabine , which are described in greater detail in the following , led to the surprising result that gemcitabine , when dissolved in an aqueous solution and filled into a tightly closed container of glass , has a pharmaceutically suitable stability if the container is characterized by a ratio of surface area ( a ) wetted by gemcitabine solution , to volume ( v ) filled with gemcitabine solution , which is less than about 3 . 4 ( cm 2 / cm 3 ). as can be inferred from fig1 - 5 , vessels with such an a / v ratio permit ready - to - use gemcitabine solutions and solution concentrates to be prepared which are stable over a long period , the ph of these solutions being able to vary over a wide range from 5 to 10 . the stability investigations furthermore led to the surprising result that gemcitabine dissolved in an aqueous solution and filled into a tightly closed container of glass , has a pharmaceutically suitable stability if the container is characterized by a ratio of the surface area of the glass container to the full - to - the - edge capacity of less than about 4 . 6 ( cm 2 / cm 3 , at / rv ). as can be inferred from fig7 - 10 , vessels with such an at / rv ratio permit ready - to - use gemcitabine solutions and solution concentrates to be prepared which are stable over a long period , the ph of these solutions being able to vary over a wide range from 8 to 10 . as can be seen from fig6 , sufficient stability is attained even at a ph of 5 when the at / vr ratio is below 3 . 3 ( cm 2 / cm 3 ). there is no prior indication in the state of the art for this completely surprising phenomenon , which has been observed as an expression of a dependency of the stability of aqueous , dissolved gemcitabine on a geometric parameter of the container . the inventive solutions range in concentration from 0 . 05 to 16 . 0 mg of gemcitabine per milliliter of solvent . preferably , the concentration of the gemcitabine is 10 mg / ml . moreover , the solutions may contain free gemcitabine base or a physiologically acceptable acid addition salt thereof . preferably , the free gemcitabine base , and especially the acid addition salt of the gemcitabine base with an inorganic acid , particularly gemcitabine hydrochloride , is used for the preparation of the inventive solutions . the inventive solution concentrates comprise from 16 . 0 mg to 110 . 0 mg of gemcitabine per milliliter of solvent . preferably , the concentration of gemcitabine is 50 mg / ml or 80 mg / ml . suitable solvents for inventive solutions and solution concentrates are , for example , water , ethanol , glycerin , 1 , 2 - propylene glycol , polyethylene glycol 200 to 600 , benzyl alcohol , trimethylene glycol , 1 , 3 - butylene glycol , 2 , 3 - butylene glycol , ethyl acetate , ethyl lactate , glycofurol ( tetraglycol ), solketal and urea . preferably water , ethanol , polyethylene glycol 200 to 600 or 1 , 2 - propylene glycol , and especially water , is used as the solvent . the ph of the inventive solutions and solution concentrates is adjusted by mixing a suitable ratio of the gemcitabine base with a physiologically acceptable acid addition salt thereof , preferably with gemcitabine hydrochloride . however , pursuant to the invention , it is also possible to adjust the ph with at least one physiologically acceptable acidifying and / or alkalizing agent . for example , inorganic acids and bases are suitable for this purpose , such as hydrochloric acid , sulfuric acid , sulfurous acid , nitric acid , nitrous acid , phosphoric acid , phosphorous acid , carbonic acid , sodium hydroxide , potassium hydroxide , calcium hydroxide and magnesium hydroxide ; alkali salts and alkaline earth salts , as well as alkali hydrogen salts and alkaline earth hydrogen salts of inorganic oxo acids of phosphorus , sulfur , carbon and nitrogen , such as sodium phosphate and its hydrate , sodium hydrogen phosphate and its hydrate , disodium hydrogen phosphate and its hydrate , disodium sulfate , sodium hydrogen sulfate , sodium sulfite , calcium sulfite , magnesium sulfite , calcium hydrogen carbonate , sodium carbonate , sodium hydrogen carbonate , sodium nitrate , sodium nitrite , calcium nitrite , magnesium nitrate and magnesium nitrite ; salts of chlorine , such as sodium chloride , calcium chloride and magnesium chloride , organic bases and acids such as formic acid , acetic acid , propionic acid , lactic acid , oxalic acid , malonic acid , maleic acid , tartaric acid , citric acid , pyruvic acid , benzoic acid , methanesulfonic acid , ethanesulfonic acid , p - toluenesulfonic acid , salicylic acid , ascorbic acid , tris ( hydroxymethyl -) aminomethane ( 2 - amino - 2 -( hydroxymethyl )- 1 , 3 - propane diol ( trometamol ; tris ), 1 - desoxy -( methylamino )- d - glucitol ( n - methylglucamine ; meglumin ); alkali salts and alkaline earth salts of organic bases and acids such as sodium acetate ; as well as mixtures thereof . preferably , the ph of the inventive solutions and solution concentrates is adjusted with hydrochloric acid , phosphoric acid , sulfuric acid , sodium hydroxide , sodium phosphate and its hydrates , sodium hydrogen phosphate and its hydrates , disodium hydrogen phosphate and its hydrates , acetic acid , lactic acid , citric acid , methanesulfonic acid , methanesulfonic acid , ethanesulfonic acid , tris ( hydroxymethyl -) aminomethane ( trometamol ; tris ) or 1 - desoxy -( methylamino )- d - glucitol ( n - methylglucamine ; meglumin ), especially with sodium hydroxide , hydrochloric acid , tris ( hydroxymethyl -) aminomethane ( trometamol ; tris ) or 1 - desoxy -( methylamino )- d - glucitol ( n - methylglucamine ; meglumin ). the ph can also be adjusted and / or stabilized by a buffer formed from physiologically acceptable acidifying and / or alkalizing agents . especially preferred buffers for adjusting the ph of the inventive solutions are sodium acetate , tris ( hydroxymethyl -) aminomethane ( trometamol ; tris ), 1 - desoxy -( methylamino )- d - glucitol ( n - methylglucamine ; meglumin ) and disodium hydrogen phosphate or mixtures thereof . the inventive solutions and solution concentrates optionally additionally comprise at least one tonicizing and / or at least one preservative material . as a tonicizing agent for the inventive solutions and solution concentrates , physiologically acceptable inorganic alkali or alkaline earth salts such as sodium chloride , calcium chloride , magnesium chloride , sodium sulfate , sodium carbonate and calcium hydrogen carbonate ; physiologically acceptable organic salts such as sodium lactate ; physiologically acceptable carbohydrates , such as glucose , fructose , sorbitol , mannitol , galactose , inositol , maltitol , lactose , trehalose , maltose , sucrose , dextran 1 , dextran 10 , dextran 40 , dextran 70 , starch and hydroxyethyl starch ; physiologically acceptable amino acids , peptides or proteins such as glycine , albumin and gelatins ; as well as mixtures thereof may , for example , be used . preferred tonicizing agents are sodium chloride , calcium chloride , glucose , mannitol and lactose ; sodium chloride , glucose and mannitol being particularly preferred . as preservatives for the inventive solutions and solution concentrates , chlorocresol , benzyl alcohol , esters of p - hydroxybenzoic acid , such as ethyl paraben and methyl paraben , may , for example , be used . preferred preservatives are benzyl alcohol , ethyl paraben and methyl paraben , benzyl alcohol being particularly preferred . test sample batches with a gemcitabine concentration of 10 mg / ml , produced for the stability investigations , were prepared in the following manner . to prepare the solutions , 80 % of the required water for injection purposes was taken and the gemcitabine hydrochloride was added and dissolved until a clear solution was obtained . the ph was adjusted to the desired value by adding the required amount of 1n sodium hydroxide solution or 1n hydrochloric acid ( maximum deviation ± 0 . 2 ph units ). the ph was determined potentiometrically . the formulation was diluted with water for injection purposes to the desired volume and the ph , if necessary , was adjusted once again with the necessary amounts of 1n sodium hydroxide solution or 1n hydrochloric acid ( maximum deviation ± 0 . 2 ph units ). the test solutions were sterilized by filtration and filtered under aseptic conditions into glass containers up to their nominal volume , and the glass containers were sealed with septums , flanged airtight and subsequently protected from light for 12 months at 25 ° c . and , “ under accelerated conditions ”, at 40 ° c . the ph , as a parameter of stability , was determined potentiometrically and the “ content ”, as another measure of stability , was determined by hplc at the test cycles mentioned . the results of the investigations carried out are summarized in the following table 3 . the analyses of the stability test samples gave the following results , which are summarized in table 3 . gemcitabine ( 10 mg , corresponding to 11 . 39 mg of gemcitabine hydrochloride ) dissolved in a solvent ( water for injection purposes ) and diluted to 1 . 0 ml ; the ph of the solution was adjusted with 1n sodium hydroxide / 1n hydrochloric acid ( both for injection purposes ) to values of 5 . 0 (± 0 . 2 ) and 8 . 0 (± 0 . 2 ) or 10 . 0 (± 0 . 2 ). to prepare the solutions in table 4 , water for injection purposes was added in 90 % of the required amount , followed by absolute ethanol as a further solvent also in 90 % of the required amount . the formulation was heated , 95 % of the required amount of the appropriate ph - adjusting material ( such as 5n sodium hydroxide solution / 5n hydrochloric acid ) was added and the formulation was heated once again . the gemcitabine hydrochloride was added in an amount corresponding to 100 % of that required and stirred until a clear solution was obtained , the ph being determined potentiometrically and adjusted with the required amount of the appropriate alkalizing agent ( such as 5n sodium hydroxide solution / 5n hydrochloric acid ) to the desired ph . the formulation was made up to volume with the required amount of water for injection purposes and with the further solvent ( absolute ethanol ). the heated formulation was stirred until a clear solution was obtained . the ph was checked once again and , if necessary , adjusted to the desired value with sodium hydroxide solution or hydrochloric acid . the formulation was cooled to room temperature and filtered sterile into a sterile container . the solution concentrate obtained was filled under aseptic conditions into glass containers up to their nominal volume . the flasks , sealed with a septum , were protected against light and kept at 25 ° c . and , “ under accelerated conditions ” at 40 ° c . samples for analysis were analyzed for purity ( by means of hplc ) and ph ( potentiometrically ) at the appropriate times . the analysis of the stability test samples gave the results summarized in the following table 4 . gemcitabine ( 50 mg , corresponding to 56 . 95 mg of gemcitabine hydrochloride ) dissolved in solvent ( 0 . 500 ml anhydrous ethanol , 0 . 500 ml water for injection purposes ) and diluted to 1 . 0 ml ; the ph of the solution was adjusted with 1n sodium hydroxide / 1n hydrochloric acid ( both for injection purposes ) to values of 5 . 0 (± 0 . 2 ) and 8 . 0 (± 0 . 2 ) or 10 . 0 (± 0 . 2 ). the solutions remained clear , colorless and free of visible particles and crystalline formations for a period of 12 month when kept at a temperature of 25 ° c . or 40 ° c . example 1 example 2 example 3 strength 500 mg 1000 mg 2000 mg ( 50 ml ) ( 100 mg ) ( 200 mg ) glass containers 50 h 1 ) 100 h 2 ) 250 h 3 ) gemcitabine hcl 10 mg / ml 10 mg / ml 10 mg / ml ph 5 . 5 (+/− 0 . 2 ) 8 . 0 (+/− 0 . 2 ) 9 . 5 (+/− 0 . 2 ) 1n sodium hydroxide up to ph 5 . 5 up to ph 8 . 0 up to ph 9 . 5 (+/− 0 . 2 ) (+/− 0 . 2 ) (+/− 0 . 2 ) 1n hydrochloric acid up to ph 5 . 5 up to ph 8 . 0 up to ph 9 . 5 (+/− 0 . 2 ) (+/− 0 . 2 ) (+/− 0 . 2 ) trometamol — — 0 . 20 mg / ml sodium acetate 0 . 20 mg / ml — — sodium chloride 6 . 5 mg / ml 6 . 5 mg / ml 6 . 5 mg / ml water for injection to 1 ml to 1 ml to 1 ml purposes 1 ) en iso 8362 - 1 ; glass vial of tubular glass type i 2 ) en iso 8362 - 1 ; glass vial from glass blanks type i 3 ) en iso 58363 - 5 infusion bottles from glass blanks type i example 4 example 5 example 6 strength 500 mg 1000 mg 2000 mg ( 10 ml ) ( 20 mg ) ( 40 mg ) glass containers 10 r 1 ) 20 r 1 ) 50 h 3 ) gemcitabine hcl 50 mg / ml 50 mg / ml 50 mg / ml ph 7 . 0 (+/− 0 . 2 ) 7 . 5 (+/− 0 . 2 ) 9 . 0 (+/− 0 . 2 ) 5n sodium hydroxide up to ph 7 . 0 up to ph 7 . 5 up to ph 9 . 0 (+/− 0 . 2 ) (+/− 0 . 2 ) (+/− 0 . 2 ) 5n hydrochloric acid up to ph 7 . 0 up to ph 7 . 5 up to ph 9 . 0 (+/− 0 . 2 ) (+/− 0 . 2 ) (+/− 0 . 2 ) sodium acetate 0 . 40 mg / ml — — 15 % ethanol in to 1 ml to 1 ml to 1 ml water for injection purposes 1 ) en iso 8362 - 1 ; glass vial of tubular glass type i 2 ) en iso 8362 - 1 ; glass vial from glass blanks type i 3 ) en iso 58363 - 5 infusion bottles from glass blanks type i
pharmaceutical compositions in the form of ready - to - use preparations of gemcitabine in aqueous solutions in a glass containers having specified dimensional relationships demonstrate long shelf life over a wide range of solution ph values . the ratio of the surface area of the container wetted by the solution to the volume of the solution , expressed in cm 2 to cm 3 , is less than 3 . 4 .