Ampicillin IP

Does anyone have any experience with IP ampicillin? We are treating a patient with an enterococcus peritonitis sensitive to ampicillin and gentamicin. According to the ISPD guidelines, the ampicillin dose is 125 mg/L. However, I can only find stability data for 50 mg/L in Dianeal - 2 days (NPA Peritoneal Dialysis handbook). What do other centres do? My patient will be adding the antibiotics to their Dianeal at home for overnight dialysis.

Thanks!
Maryanne McDonald
Nephrology Clinic Pharmacist
Alberta Children's Hospital