Stability of cefazolin in heparinized and nonheparinized peritoneal dialysis solutions

Stability of Drug Additives in Peritoneal Dialysis Solutions in a New Container

Objective

To evaluate the stability of gentamicin, tobramycin, netilmycin, vancomycin, cefazolin, unfractionated heparin, and low molecular weight heparin when added to four different peritoneal dialysis (PD) solutions [Extraneal (Baxter Healthcare, Castlebar, Ireland); Physioneal, Nutrineal, and Dianeal (Baxter Healthcare, Grosotto, Italy)] in new, non-PVC Clear-Flex containers.

Measurements

Gentamicin, tobramycin, netilmycin, vancomycin, cefazolin, unfractionated heparin, and low molecular weight heparin were injected into separate bags of PD solution. Samples were withdrawn at predefined sampling times and the concentration of each drug was analyzed using high-performance liquid chromatography (for gentamicin, tobramycin, vancomycin, and cefazolin), or bioassay (for netilmycin, gentamicin, and tobramycin in Nutrineal), or coagulation methods (heparins).

Results

Netilmycin, vancomycin, cefazolin, and heparin in Physioneal, Nutrineal, Extraneal, and Dianeal were stable for at least 24 hours at 25°C and for an additional 4 hours at 37°C. Gentamicin in Nutrineal, Extraneal, and Dianeal was stable for at least 24 hours at 25°C and for an additional 4 hours at 37°C; gentamicin in Physioneal was stable for less than 24 hours at 25°C. Tobramycin in Nutrineal and Extraneal was stable for at least 24 hours at 25°C and for an additional 4 hours at 37°C; tobramycin in Physioneal and Dianeal was stable for less than 24 hours at 25°C.

Stability of Cefazolin Sodium in Four Heparinized and Non-Heparinized Dialysate Solutions at 38°C

Background

Intraperitoneal administration of antibiotics is often required in the treatment of peritoneal dialysis-associated peritonitis. Extended use and heating may affect drug stability. The objective of our study was to determine the stability of cefazolin sodium (125 mg/L and 500 mg/L) in heparinized and non-heparinized dextrose-containing peritoneal dialysis solution (Dianeal PD-2; Baxter Healthcare, Deerfield, Illinois, USA) containing 1.5%, 2.5%, or 4.25% dextrose, or 7.5% icodextrin, the new colloid formulation (Extraneal; Baxter), at 38°C for 4 days.

Methods

Three poly-vinyl chloride containers of each dialysis fluid were stored at 38°C for 4 days. Samples were taken after the bags were mixed and allowed to stand for 2 minutes. Two 500-μL samples were collected from each bag at hours 0, 12, 24, 36, 48, 60, 72, 84, and 96. Samples were then analyzed by high-performance liquid chromatography (HPLC) in our laboratory. In order to establish the stability-indicating nature of the method, drugs 1.0 mg/mL, vehicles, and their mixtures were subjected to a forced degradation. This is done by acid (2.0 mol/L HCl) and base (2.0 mol/L NaOH) hydrolysis, oxidation (H2O20.3%), and heat at 80°C. Samples were analyzed every 30 minutes until approximately 25% of the drug's peak disappeared. The drug was considered stable if its concentration exceeded 90% of the original.

Results

For all Dianeal PD-2 peritoneal dialysis solution containing 1.5%, 2.5%, and 4.25% dextrose, cefazolin sodium was considered stable at 38°C for 60 hours at low cefazolin concentrations (125 mg/L), both with and without heparin, and for 48 hours at high cefazolin concentrations (500 mg/L). Cefazolin sodium was considered stable at 38°C in icodextrin for 48 hours at low cefazolin concentrations in heparinized and non-heparinized solutions, and at high concentrations only in non-heparinized dialysate, not in heparinized dialysate. Cefazolin sodium was considered stable at 38°C in icodextrin for 60 hours at high concentrations when heparinized.

Conclusion

Cefazolin sodium was stable in all four non-heparinized dialysate fluids for at least 48 hours at 38°C. In heparinized icodextrin dialysate, high concentrations of cefazolin sodium were not stable for extended periods of time. Extended use and heating of dialysate containing cefazolin may adversely affect patient outcome.

Short-Dwell Cycling Intraperitoneal Cefazolin plus Ceftazidime in Peritoneal Dialysis Patients

Background

Current guidelines suggest that intraperitoneal (IP) antibiotics should be administered only in a long peritoneal dialysis (PD) dwell (≥ 6 hours). The long dwell might result in low ultrafiltration and volume overload. We aim to examine plasma and dialysate concentration of cefazolin and ceftazidime after IP administration in a short-dwell (≤ 2 hours) automated cycling exchange.

Methods

Stable PD patients without peritonitis were invited to participate in the present study. Patients underwent 5 2-liter exchanges of PD fluid over 10 hours by the PD cycling machine without last fill or additional dwell. Cefazolin and ceftazidime (20 mg/kg each) were added to the first 5-liter bag of 2.5% dextrose PD fluid that was placed on the warmer of the PD cycling machine. Plasma samples were collected at 12 time-points over 24 hours. Dialysate samples from each exchange were also collected. Antibiotic concentrations in plasma and dialysate were then determined by high-performance liquid chromatography (HPLC).

Results

Six stable PD patients without peritonitis participated in the study. Dialysate cefazolin and ceftazidime were consistently high throughout the PD session in all patients (26 - 360 mg/L). Plasma cefazolin and ceftazidime exceeded the minimal inhibitory concentration (MIC) for susceptible organisms (≤ 8 mg/L) within 2 hours (cefazolin 28.5 ± 8.0 and ceftazidime 12.5 ± 3.4 mg/L), peak at 10 hours (51.1 ± 14.1 and 23.0 ± 5.2 mg/L) and sustained well above the MIC at 24 hours (42.0 ± 9.6 and 17.1 ± 3.1 mg/L).

Conclusions

The short-dwell cycling IP cefazolin and ceftazidime could provide adequate plasma concentration for up to 24 hours. Daily short-dwell cycling IP cefazolin and ceftazidime might be used to treat peritonitis in PD patients already using a PD cycling machine as well as selected continuous ambulatory PD (CAPD) patients who need shorter dwells during peritonitis due to increasing peritoneal solute transport.

Intraperitoneal Administration of Drugs in Peritoneal Dialysis Patients: A Review of Compatibility and Guidance for Clinical Use

Peritoneal dialysis (PD) is an effective home-based therapy for end-stage renal failure. Intraperitoneal administration of drugs to PD patients is particularly important for the treatment of peritonitis. Clinicians need to know that the administered drug is compatible with both the PD solution and its container. A detailed literature search on drug compatibility and stability was performed and results of all published stability studies are presented for all drugs, PD solutions, and containers studied. These data will aid clinicians managing PD patients and provide a resource to demonstrate which drugs have been shown to be stable in various PD solutions and solution containers. This is important information to assist clinicians in applying effective treatments, in particular, for peritonitis.