title: Ultrafiltration characteristics of glucose polymers with low polydispersity.
abstract: BACKGROUND
  Icodextrin, a glucose polymer with a polydispersity [ratio of weight-average molecular weight (Mw) to number-average molecular weight] of approximately 2.6, has been shown, compared with glucose, to provide superior ultrafiltration (UF) efficiency [ratio of UF to carbohydrate (CHO) absorbed] when used as an osmotic agent during a long-dwell peritoneal dialysis exchange. In an experimental rabbit model, we evaluated the effect of Mw on the UF and UF efficiency of glucose polymers with low polydispersity.
  
  
  METHODS
  A crossover trial in female New Zealand White rabbits (2.20 - 2.65 kg) with surgically implanted peritoneal catheters evaluated two glucose polymers at nominal concentrations of 7.5 g/dL: a 6K polymer (Mw: 6.4 kDa; polydispersity: 2.3) and a 19K polymer (Mw: 18.8 kDa; polydispersity: 2.0). Rabbits were randomized to receive either the 6K (n = 11) or the 19K (n = 12) solution during the first exchange (40 mL/kg body weight). The alternative solution was evaluated in a second exchange 3 days later. During each 4-hour dwell, the UF and total glucose polymer CHO absorbed were determined.
  
  
  RESULTS
  The UF was higher for the 6K (p < 0.0001) than for the 19K polymer (mean ± standard deviation: 73.6 ± 30.8 mL vs. 43.0 ± 20.2 mL), as was the amount of CHO absorbed (42.5% ± 9.8% vs. 35.7% ± 11.0%, p = 0.021). In spite of higher CHO absorption, an approximately 50% higher (p = 0.029) UF efficiency was achieved with the 6K polymer (28.3 ± 18.8 mL/g) than with the 19K polymer (19.0 ± 11.3 mL/g). The results were independent of the order of the experimental exchanges.
  
  
  CONCLUSIONS
  Glucose polymers with low polydispersity are effective osmotic agents in a rabbit model. The low-Mw polymer was more effective at generating UF and had a higher UF efficiency, but those results came at the expense of the polymer being more readily absorbed from the peritoneal cavity.
authors.affiliation: Medical Products (Renal), Baxter Healthcare Corporation, McGaw Park, Illinois, USA. ken_leypoldt@baxter.com
authors.forename: John K
authors.initials: JK
authors.lastname: Leypoldt
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Hoff
authors.forename: Dean
authors.initials: D
authors.lastname: Piscopo
authors.forename: Seraya N
authors.initials: SN
authors.lastname: Carr
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Svatek
authors.forename: Clifford J
authors.initials: CJ
authors.lastname: Holmes
mesh_terms: D000042:Absorption; D000818:Animals; D015314:Dialysis Solutions / Q000493:pharmacokinetics*; D004195:Disease Models, Animal; D005260:Female; D005936:Glucans / Q000493:pharmacokinetics*; D005947:Glucose / Q000493:pharmacokinetics*; D000077607:Icodextrin; D008970:Molecular Weight; D009995:Osmosis / Q000187:drug effects; D010530:Peritoneal Dialysis; D011817:Rabbits; D051437:Renal Insufficiency / Q000378:metabolism* / Q000628:therapy; D014462:Ultrafiltration
chemical_list: D015314:Dialysis Solutions; D005936:Glucans; D000077607:Icodextrin; D005947:Glucose