amikacin is a preferred aminoglycoside in the icus and in ventilator patients due to its better activity against acinetobacter baumannii bacteria than tobramycin . in aerosol studies , a nebulizer dose of 400 mg amikacin led to mean sputum concentrations of 11 , 900 μg / ml with a wide variability with median & lt ; 6400 μg / ml . niederman et al , bay 41 - 6551 inhaled amikacin achieves bactericidal tracheal aspirate concentrations in mechanically ventilated patients with gram - negative pneumonia ( intensive care medicine 38 : 263 - 271 , 2012 ) a pharmacokinetic study ats 2010 new orleans , la .). the vibrating plate nebulizer used in this study triggered only on inspiration and delivery time of a 2 . 7 ml formulation averaged 50 minutes . if run continuously , the pari vibrating plate nebulizer has about 15 % delivery efficiency and can deliver a 6 ml dose in 12 minutes . hahn et al in vitro assessment of a novel nebulizer for mechanically ventilated patients based on the eflow ® technology , isam 2009 , monterey calif . in the phase 2 cf fosfomycin / tobramycin study , the nebulizer dose of tobramycin was only 20 mg , with estimated 5 mg delivered to the lung . this illustrates the synergy seen with a combination of fosfomycin and an aminoglycoside . however , relying on synergy is not appropriate in vap patients where the bacteria may be resistant to fosfomycin and is a life threatening condition . the doses of aminoglycosides at first examination may seem excessive ; however , sputum macromolecules bind aminoglycosides , so up to 90 % of aminoglycoside is bound and therefore inactive . therefore , with aerosol aminoglycoside monotherapy , a sputum concentration that is a least tenfold higher than the mic 90 is considered necessary , and higher - fold concentrations , up to 25 - fold may provide increased bacterial killing ( mendelman am rev rispir dis 1985 ; 132 : 761 - 5 ). fosfomycin interferes with the sputum antagonism , ( maccleod , supra ), thus even if the bacteria are fosfomycin - resistant , there may be some clinical benefit to the combination by increasing the bioactive concentrations of the aminoglycoside . the optimally effective dose of fosfomycin is likely at least 15 mg delivered to the lung , with nebulizer doses ranging from 50 to 200 mg depending on nebulizer efficiency . this is based from the successful phase 2 cf trial ( trapnell et al ., supra ), which showed decreased bacterial density of both pseudomonas and staphylococcus aureus in the subset of patients who were co - infected , with approximately 20 mg delivered to the lung . in this trial , an estimated 40 mg delivered dose of fosfomycin was more efficacious in killing staphylococcus than the estimated 20 mg dose , showing that a higher dose may be better . the most soluble fosfomycin salt is the disodium salt and is preferable although other salts are possible — such as calcium and tromethamine . the recent development of vibrating plate nebulizers , particularly one by pari , enables particle sizes less than 5 microns . see wo 2005 / 048982a2 . membranes having a plurality of small apertures therein can produce mean particle sizes less than 5 microns and in the range of 3 . 5 microns . this is accomplished by making the porous holes smaller during the laser drilling process . other vibrating plate membranes by pari have a 4 . 5 micron average size particle as does the vibrating plate nebulizer introduced by aerogen / nektar . similarly , there are small particle jet nebulizers that can produce 2 - 3 micron size particles . current ultrasonic nebulizers produce an average particle size of 5 microns using a 2 . 7 mhz driving frequency . ultrasonic nebulizers can create smaller particles by increasing the frequency of the ultrasonic generator . no high frequency ( 2 . 3 mhz ) nebulizers are currently commercially available in the united states or europe at this time , but would have a 2 - 3 micron particle size . in addition , ultrasonic nebulizers heat the nebulizer solution and this may lead to drug degradation during therapy , for this reason , their use has fallen out of favor . the present invention includes the use of humidification as a technique to improve the tolerability of hypertonic solutions delivered as an aerosol . the creation of an aerosol with a small particle size from a hypertonic solution can produce a composition of small particles that carry a desirable therapeutic dose but are poorly tolerated due to a high osmolality , i . e ., on the order of threefold or greater of normal osmolality , ( e . g ., ≧ 930 mosm / kg ). adding humidification to the aerosol yields an aerosol composition that has a reduced osmolality and is preferably close to isotonic or less than twofold normal osmolality ( e . g ., & lt ; 620 mosm / kg ). the humidification is created by an inline humidifier to decrease the osmolality to a range from greater than threefold to less than twofold normal osmolality and may vary depending on the nature of the original hypertonic solution . the particle size of non - humidified aerosol such as the hygroscopic growth of a 4 micron particle may lead to much more dilution than growth of sub 3 micron particle . in such hypertonic solutions , the permanent ion in solution is preferably greater than 40 mequil / l . the humidification can be applied to aerosols formed from a variety of hypertonic solutions where paired tolerability is desired . examples include any small molecular weight drugs that require high concentrations for efficacy , or compounds that are salts with multiple anions or cations that create a high osmolar load in solution . in the aspect of the invention below , aminoglycoside / fosfomycin combinations are hypertonic on administration but close to isotonic upon delivery by the advantage of increased humidification compared to ambient air . for instance , if the particle size grows on average from 3 . 5 to 4 . 5 microns , the dilution is a function of the cube of the radius or 4 . 91 / 11 . 3 . therefore , the use of small particle aerosol with subsequent hygroscopic growth due to humidification would substantially reduce the osmotic load on the lung . with a larger initial particle size , the effect would be similar . for example , the growth from a 5 to 6 micron particle would lead to a dilution of 15 . 6 / 27 . if particles are allowed to grow much larger than 5 microns , tolerability is not the primary issue , as little will be deposited in the airways due to “ rain out ” in the ventilator and endotracheal tubing . this was shown in the seminal studies by palmer ( supra ) on the deleterious effect of humidification on total drug delivery . these studies mostly utilized jet nebulizers that have an average of 4 - 5 micron particles prior to growth due to humidification . the hygroscopic growth was responsible for rain out and less drug delivered to the airways . for instance , applying the ratio of 4 . 91 / 11 . 3 , if a hypertonic solution is used with a nebulizer that has a 3 . 5 micron average particle , an osmolality of up to 710 would become , on average , isotonic . slightly hypertonic formulations can be tolerated by the lung , and it is likely a formulation with an osmolality of up to 800 would be well tolerated by applying the humidification technique described herein . the pari inline nebulizer designed for ventilator use can be outfitted with a small pore membrane , has a current volume capacity of 10 ml , and has a rate of delivery of 0 . 5 - 0 . 6 ml / minute . although it is currently not configured for triggering on inspiration , a nebulizer may be so configured when operably connected to the control system of the ventilator . particle size would be estimated at 3 . 2 microns . a formulation of 10 ml , with 100 to 300 mg fosfomycin and 300 to 600 mg of amikacin at the 15 % efficiency rate would provide adequate killing for staphylococcus aureus and pseudomonas . an ideal formulation would contain at least 20 meq / l of chloride anion after dilution . the estimated osmolality of a solution of 50 mg / ml amikacin and 20 mg / ml of fosfomycin , with chloride anion , adjusted to a ph between 4 . 5 and 7 . 5 is approximately 750 - 850 osm / l . if diluted by humidification , this would likely be close to the isotonic range when deposited in the airways . to vary the delivered dose , a smaller or larger volume could be used , or alternatively or in combination , trigger delivery on inspiration phase of breathing to increase the deposition amount . a fosfomycin / amikacin solution having a ratio of 2 . 5 - 2 . 6 : 1 may be prepared as follows : fosfomycin disodium ( 12 . 90 g , 10 . 00 g free acid ) was dissolved in 250 ml of water and the ph was adjusted to 7 . 41 by the dropwise addition of 4 . 5 n hcl ( estimated 1 ml ). 25 gm amikacin base was added to the resulting solution . the ph of the solution was adjusted to 7 . 60 by the addition of 4 . 5 n hcl ( total amount of 4 . 5 n hcl was 1 . 7 ml ). the solution was diluted to 500 ml with water and filtered through a 0 . 2 μm nalge nunc 167 - 0020 membrane filter for sterility . the chloride content can be calculated by using 1 . 7 ml of 4 . 5n hcl in 50 l total for a total 306 mg chloride . as 1 meq cl = 35 . 5 mg in 1 l then in 50 ml 1 meq cl = 1 . 775 mg . therefore , 306 mg / 1 . 775 mg = 172 . 4 meq / l . the osmolality of this formulation was measured at 592 mosm / kg , which is above the normal physiologic value of 310 mosm . the 2 : 5 - 2 . 6 : 1 fosfomycin / amikacin solution was prepared as above . using an inline electronic vibrating late nebulizer ( pari , starnberg gr ), the formulation was nebulized in dry ( 4 %) and humid ( 100 %) humidity . the mean particle size , as measured by malvern x laser particle sizer , was 2 . 9 μm under dry conditions , increasing to 3 . 2 μm under 100 % humidity . since the volume of sphere is function of the third power of the radius , the following equation yields the dilution factor : thus , the formulation on average is diluted by a factor of 0 . 75 , indicating the delivered formulation has an osmolality of 592 × 0 . 75 = 444 mosm / kg . randomized , double - blind , placebo - controlled , dose - escalation phase 1b study of aerosolized amikacin and fosfomycin delivered via the pari investigational eflow ® inline nebulizer system in mechanically ventilated patients a dry powder fosfomycin , liquid amikacin solution can be prepared by use of 200 mg neat dry powder disodium fosfomycin filled in a glass vial or two - part dry liquid syringe . in either a separate syringe , blow fill seal container , or a two - part syringe , 500 mg of amikacin base dissolved in 10 ml of sterile water , with the ph adjusted to a range of 4 . 5 to 7 . 5 with hcl . the two components are then mixed together giving a solution with 20 mg / ml fosfomycin , 50 mg / ml amikacin . the osmolality of the solution would be approximately 600 mosm / kg , but could vary up to 10 % depending on the amount of hcl used to adjust the ph of the amikacin solution . also by employing the chlorine counter anion with the amikacin base , the sulfate salt of amikacin is not used . a treatment regimen was designed to control safety , efficiency , tolerability and to further elucidate systemic and tracheal aspirate pharmacokinetics of nebulized amikacin / fosfomycin in patients with a clinical diagnosis of vap following delivery of 2 ml , 4 ml , 6 ml , 8 ml , and 10 ml and doses via the pari investigational eflow ® inline nebulizer system in mechanically ventilated patients . adult patients having a clinical diagnosis of vap , with a gram - positive or gram - negative organism in a tracheal aspirate sample were expected to be on mechanical ventilation for 3 days . each adult patient received 3 escalating doses of a mixture of 50 mg / ml amikacin and 20 mg / ml fosfomycin , with doses separated by 24 ± 2 hours ( table 1 ). on day 3 , patients received 2 blinded , randomized treatments ( amikacin / fosfomycin and volume - matched placebo [ 0 . 9 % normal saline ]), separated by 2 hours . all treatments were administered with a single patient , multi - treatment nebulizer ( investigational eflow ® inline nebulizer system ; pari pharma gmbh , starnberg , germany ), positioned in the inspiratory tubing between the ventilator and the patient . the nebulizer remained inline until all treatments were delivered . as documented herein , the nebulizer has a vibrating perforated membrane and generates an aerosol with small droplets and narrow size distribution , which is optimal for deposition in the lower airways . concentrations of amikacin and fosfomycin were measured in tracheal aspirate and plasma samples obtained during the 24 hours after each dose , and the maximum concentration ( c max ) was determined . adverse events were assessed from the first dose until 24 hours after the last dose was received . in tracheal aspirate samples obtained from each patient after each dose of amikacin / fosfomycin solution for nebulization . each amikacin cmax value was 89 fold higher than the minimum inhibitory concentration for 90 % ( mic 90 ; 32 μg / ml ) of 1477 pseudomonas aeruginosa isolates described in a recently published isolate collection . zhanel et al ., diagn microbiol infect dis 2011 , 69 : 291 . mean amikacin cmax after the 6 ml dose was ≧ 406 - fold higher than the mic 90 for p . aeruginosa ( fig2 ). each fosfomycin cmax value was ≧ 54 - fold higher than the published mic 90 value for 148 isolates of methicillin - resistant staphylococcus aureus ( mrsa ; 32 μg / ml ). mean fosfomycin cmax after the 6 ml dose was 281 - fold higher than the mic 90 for mrsa ( fig3 ). six hours after dosing , all fosfomycin tracheal aspirate concentrations remained ≧ 2 . 2 - fold above the mic 90 for mrsa . plasma concentrations were & gt ; 2000 - fold lower than concentrations in tracheal aspirates : the highest observed amikacin plasma concentration was 1 . 4 μg / ml ; this is less than the recommended peak concentration ( 35 μg / ml ) after a systemic dose . the highest observed fosfomycin plasma concentration was 0 . 8 μg / ml . no adverse event was considered by the clinical investigator related to study - drug treatment . no changes in oxygen saturation or peak airways pressures were noted in response to study drug . all patients were alive 28 days after completing the study . high tracheal aspirate concentrations of amikacin and fosfomycin were achieved in mechanically ventilated patients with vap after aerosolized administration of amikacin / fosfomycin solution for nebulization with an inline nebulizer system . systemic exposures to amikacin and fosfomycin were much lower than tracheal aspirate levels . amikacin / fosfomycin solution for nebulization was well tolerated . the combination antibiotic amikacin / fosfomycin ( 50 mg / ml amikacin and 20 mg / ml fosfomycin ) formulation was delivered via the pari investigational eflow ® inline nebulizer system in mechanically ventilated patients . a placebo : 0 . 9 % normal saline , having a volume matched to the antibiotic dosing schedule was delivered via the pari investigational eflow ® inline nebulizer system in mechanically ventilated patients . the eflow ® inline nebulizer system was positioned in the inspiratory tubing between the puritan bennett 840 ventilator and the patient . once in place , the nebulizer remained inline until all study - drug doses were delivered . humidification continued during the nebulization of the formulation and the delivery of the entire dose . patients are male or female between 18 years and 80 years of age with clinical diagnosis of vap or vat , a gram - positive or gram - negative bacteria on gram stain of the tracheal aspirate and were expected to be on mechanical ventilation for at least three days . these results support further clinical trials of amikacin / fosfomycin solution for nebulization in mechanically ventilated patients with vap or vat . these results demonstrate that high sputum concentrations of amikacin and fosfomycin were achieved in mechanically ventilated patients with vat or vap after aerosolized administration with an inline nebulizer system . a glp ( good laboratory practice ) study was performed using 24 beagle dogs allocated to four dose groups ( three males and three females per group ) and exposed to aerosol generated with the pari investigational eflow ® inline nebulizer system using a closed - faced mask fitted with a mouth tube . the aerosols contained either control ( water for injection ) in group 1 or a combined formulation containing 50 mg / ml amikacin and 20 mg / ml fosfomycin ph adjusted with hcl for groups 2 to 4 . aerosol concentrations were determined on days 1 and 7 . the treatment period was for seven days with termination of the dogs on day 8 . the average daily achieved dose of amikacin / fosfomycin for each group was 32 . 1 : 12 . 4 mg / kg / day ( a 2 . 59 : 1 ratio ) ( group 2 ); 63 . 0 : 24 . 7 mg / kg / day ( 92 . 55 : 1 ratio ) ( group 3 ); and 116 . 8 : 47 . 5 mg / kg / day ( 92 . 46 : 1 ratio ) ( group 4 ). the highest estimated pulmonary dose was 29 . 2 mg / kg / day amikacin and 11 . 9 mg / kg / day fosfomycin . the particle size distribution ( mmad [ mass median diameter ]) based on analytical methods was determined to be respirable averaging 2 . 80 μm ( gsd = 1 . 778 ) for amikacin and 2 . 75 μm ( gsd = 1 . 670 ) for fosfomycin . the aerosol was well tolerated by all dogs . there were no treatment - related adverse effects based on clinical observations , body weights , food consumption , ophthalmoscopy , or electrocardiography . any changes to clinical pathology values observed were attributed to normal animal variation . no treatment - related abnormalities were observed on necropsy . no treatment - related adverse findings were observed upon histologic evaluation of tissues . toxicokinetic parameters were estimated using winnonlin pharmacokinetic software version 5 . 2 . 1 ( pharsight corp .). a non - compartmental approach consistent with the extravascular route of administration was used for parameter estimation . all parameters were generated from individual amikacin and fosfomycin concentrations in plasma from days 1 and 7 . plasma amikacin and fosfomycin concentration vs . time profiles were consistent with the inhalation dose route whereby a post - dose absorption phase was followed by a biphasic bi - phasic decline in plasma concentrations . systemic exposure to both amikacin and fosfomycin was generally comparable between males and females and there was no clear indication of accumulation following repeat dosing . the peak plasma levels ( cmax ) for the high dose level on day 7 ranged from 13 . 2 to 39 . 3 μg / ml for amikacin and 8 . 7 to 28 . 73 μg / ml for fosfomycin . based on the results of the study , significant exposure occurred following aerosol exposure to beagle dogs with no adverse effects observed over the 7 - day treatment period . the noael was considered to be 116 . 8 amikacin and 47 . 5 fosfomycin mg / kg / day delivered as a combination antibiotic aerosol . this is approximately 30 - fold the estimated exposure to humans . synergism of the amikacin and fosfomycin combination against resistant , gram - negative pathogens sixty - two amikacin - resistant strains were selected from a worldwide antimicrobial surveillance collection ( sentry ), which contains 35 , 000 organisms from six continents ( 56 / 62 organisms collected in 2011 ). the 62 isolates of acinetobacter baumannii , pseudomonas aeruginosa , and klebsiella pneumoniae had an amikacin minimum inhibitory concentration ( mic ) of & gt ; 32 μg / ml ( clinical and laboratory standards institute [ clsi ]: intermediate or resistant ; european committee on antimicrobial susceptibility testing [ eucast ]: resistant ). each isolate was tested against amikacin ( 0 . 25 - 1024 μg / ml ), fosfomycin ( 0 . 1 - 409 . 6 μg / ml ), and amikacin / fosfomycin ( 5 : 2 ratio ) using clsi methods ( agar dilution with supplements ). control strains included a range of mic values ( amikacin : 0 . 25 - 1024 μg / ml ; fosfomycin : 0 . 1 - 409 . 6 μg / ml ). for 21 a . baumannii , 21 p . aeruginosa , and 20 k . pneumoniae strains , amikacin ( table 1 ) and fosfomycin ( table 2 ) mic values were reduced with the amikacin / fosfomycin combination . for control stains , 100 % of amikacin and 91 . 7 % of fosfomycin mic values were within published ranges . for a . baumannii strains , the effect was most pronounced for strains with high amikacin resistances ( mic , & gt ; 1024 μg / ml ); for these 5 isolates , amikacin mic values were reduced to & lt ; 256 μg / ml with the amikacin / fosfomycin combination . for 11 of 21 p . aeruginosa strains , amikacin mic values remained stable (± one log 2 dilution step ) with the addition of fosfomycin . for the other 10 strains , amikacin mic values decreased & gt ; fourfold when fosfomycin was added . for 9 of 20 k . pneumoniae strains , amikacin mic values remained stable with the addition of fosfomycin . for the other 11 strains , amikacin mic values decreased more than fourfold when fosfomycin was added ( decrease & gt ; 32 - fold for 6 / 11 strains ). overall , median mic values for amikacin ( table 1 ) and fosfomycin ( table 2 ) each decreased twofold with the amikacin / fosfomycin combination . addition of fosfomycin reduced the amikacin concentration required to inhibit all 62 isolates from & gt ; 1024 to & lt ; 256 μg / ml ( fig4 ). combining amikacin in a 5 : 2 ratio with fosfomycin significantly enhanced the potency of amikacin against 62 gram - negative , amikacin - resistant pathogens . interactions between amikacin and fosfomycin varied by isolate , and ranged from non - detectable to high - level synergy . these results support development of the amikacin / fosfomycin combination for aerosolized administration where high drug levels can be achieved . inhalation solutions are designed to be tolerable when administered , and there is substantial literature identifying a few critical parameters that influence tolerability . the ph of the solution , the osmolality of the solution , and the presence of permeable anions in the solution all determine whether a solution can be acceptably delivered to the lungs without triggering adverse reactions ( cough , bronchospasms , etc ). a two - part formulation of amikacin and fosfomycin ( which is mixed immediately prior to use ) was designed so that the final mixed solution would be as close to neutral in ph as possible , while maximizing the stability of each component . fosfomycin is most stable under basic conditions , which requires the amikacin solution to be lower in ph , so that the resulting mixture is neutral . an acidic , citrate - buffered formulation of amikacin ( based on the commercial injectable formulation ) was compared to an unbuffered formulation at ph 7 . a mixture experiment was performed by mixing each into fosfomycin solutions at increasingly basic ph values ( which enhance the solutions stability of fosfomycin ). results are in table 3 . another formulation uses fosfomycin disodium as a powder mixed with the amikacin solutions . the two amikacin formulations were mixed with the appropriate amount of fosfomycin disodium powder and the resulting solution ph was evaluated . results are in table 4 . the data show that all final solutions fall within a ph range considered tolerable with the lung physiology (˜ 4 . 2 - 8 . 0 ). amikacin at ph 7 when mixed with fosfomycin at ph 8 , 9 , or 10 , produces a final solution ph of 7 . 51 - 7 . 56 . fosfomycin is increasingly stable as the ph becomes more basic . therefore , more basic formulations of fosfomycin can be created if needed . the data also support a powder formulation comprising amikacin solutions mixed with the required amount of fosfomycin disodium powder to yield a resulting solution with an acceptable ph ( 6 . 87 - 7 . 58 ). a two - part liquid formulation with the amikacin component at a neutral ph is also beneficial and would be well tolerated by a patient . the amikacin fosfomycin inhalation system ( afis ) consists of amikacin solution ( ams ) ( 3 ml sterile unit dose ampoule , 100 mg / ml ), fosfomycin solution ( ffs ) ( 3 ml sterile unit dose ampoule , 40 mg / ml ) and the pari investigational eflow ® inline nebulizer system . ams and ffs were dispensed to the nebulizer reservoir to create the amikacin fosfomycin admixture ( afa ). the nebulizer delivered the aerosolized afa directly into the inspiratory arm of a ventilator for patients receiving mechanical ventilation . amikacin base , ep is compendial ( ph eur ) and is manufactured by acs dobfar s . p . a under dmf 13762 . the api is manufactured in bergamo , italy . fosfomycin disodium is compendial ( ph eur ) and is manufactured by ercros , s . a . under dmf 14341 . the api is manufactured in madrid , spain . rather than commercial amikacin sulfate , the amikacin base is the starting material . amikacin base has a ph of approximately 11 , and large amounts of hcl are required to neutralize the ph . in the two - part formulation ( used to combine with equal volumes of 40 mg / ml fosfomycin to generate the final formulation of 50 mg / ml amikacin , 20 mg / ml fosfomycin ), the amikacin 100 mg / ml solution has a final ph of 7 . 5 - 7 . 6 and has an osmolality of approximately 533 mosmol / kg , of which only approximately 170 mosmol / kg is due to the amikacin , the balance is from the chloride anion . this concentration of chloride anion provides the permeant anion that will prevent cough . in contrast , the starting ph of amikacin sulfate is 3 . 5 - 5 . 5 and little or no hcl is needed to neutralize the ph of the solution . note that in the neiderman paper ( supra ) amikacin sulfate was delivered as an aerosol to patients with vap , and bronchospasm was reported in some patients . in contrast , none was seen in the study presented in example 3 . as described above , a final formulation has an amikacin concentration of 50 mg / ml and chloride anion concentration of approximately 265 meq / liter . the low end of an acceptable range would be an amikacin concentration of 25 mg / ml and chloride anion concentration of approximately 130 meq / liter ; however , as low as 30 meq / liter could be used with another anion in addition to chloride . the high end of the amikacin concentration would be 100 mg / ml and a chloride anion concentration of approximately 540 meq / liter . this formulation yields an osmolality of 900 mosmol / l , and any increase would prevent dilution of the formulation with humidity sufficient to make it tolerable . the flow diagram depicting the steps of the manufacturing process of amikacin solution is provided in fig5 . the flow diagram indicates where each raw material enters the manufacturing process . 1 . add the calculated amount of water for injection ( wfi ) to the stainless steel tank . 2 . add the calculated amount of amikacin to the tank and mix until dissolved . 3 . add 90 % of the calculated amount of hcl and mix for 5 - 10 minutes . 4 . titrate the amikacin - hcl solution with remaining hcl until solution reaches ph 7 . 0 ± 0 . 3 . 5 . bring the solution to final mass with wfi and mix for 10 - 15 minutes . 6 . filter the solution through a 0 . 22 micron filter into a holding tank . 7 . filter the solution through two 0 . 22 micro filters in series . 8 . use blow / fill / seal equipment to form the ldpe ampoule , fill to a target weight and then seal the ampoule . 9 . perform 100 % visual inspection and integrity testing on ldpe ampoule . 10 . foil overwrap ampoules individually . 11 . perform 100 % leak detection on foil overwrapped ampoules . the flow diagram depicting the steps of the manufacturing process of fosfomycin solution is provided in fig6 . the flow diagram indicates where each raw material enters the manufacturing process . 1 . add the calculated amount of wfi to the stainless steel tank . 2 . add the calculated amount of fosfomycin to the tank and mix until dissolved . 3 . add 90 % of the calculated amount of hcl and mix for 5 - 10 minutes . 4 . titrate the solution with remaining hcl until solution reaches ph 8 . 0 ± 0 . 3 . 5 . bring the solution to final mass with wfi and mix for 10 - 15 minutes . 6 . filter the solution through a 0 . 22 micron filter into a holding tank . 7 . filter the solution through two 0 . 22 micro filters in series . 8 . use blow / fill / seal equipment to form the ldpe ampoule ; fill to a target weight ; and then seal the ampoule . 9 . perform 100 % visual inspection and integrity testing on ldpe ampoule . 10 . foil overwrap ampoules individually . 11 . perform 100 % leak detection on foil overwrapped ampoules . in a scaled - up commercial the manufacturing process may be transferred to other contract manufacturing sites that specialize in blow / fill / seal technology . such that both solutions will be contained in one overwrapped ampoule having dual chambers and a single opening . in use , both solutions will be dispensed into the nebulizer at the same time .