12 Biocompatible Solutions for Peritoneal Dialysis Alberto Ortiz 1 , Beatriz Santamaria 2 and Jesús Montenegro 3 1 IIS-Fundacion Jimenez Diaz and Universidad Autonoma de Madrid, Madrid 2 Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid (CSIC-UAM), Madrid 3 Servicio de Nefrologia, Bilbao Spain 1. Introduction In 1978, a simplified technique for peritoneal dialysis (PD) using plastic bags and glucose as osmotic agent allowed PD to become accepted as a home-based renal replacement therapy. However, PD was marred by complications including peritonitis and loss of function of the peritoneal membrane. Both complications may be favored by the bioincompatibility of PD solutions. The composition of PD solutions has evolved over the years, building on a better understanding of the biocompatibility and of technical advances that enable the commercial viability of certain solutions. The main osmotic agent used to obtain ultrafiltration is glucose. Conventional glucose-containing PD solutions are lactate-buffered, acidic pH solutions presented in single chambered bags. The use of new manufacturing techniques, buffer presentation, and new osmotic alternatives to glucose have resulted in more biocompatible glucose containing PD solutions that have a lower concentration of glucose degradation products (GDP) and a neutral, more physiological pH, as well as in glucose-free solutions. 2. Composition of PD solutions PD solutions are sterile and contain water, electrolytes, a buffer and an osmotic agent (Table 1). Electrolyte concentrations (Na + , Cl - , Ca ++ , Mg ++ ) display little variation between different PD solutions.  Water  Electrolytes: Na + , Cl - , Ca ++ , Mg ++  Buffer: lactate, lactate / bicarbonate or bicarbonate  Osmotic agent glucose, icodextrin or amino acids  Glucose degradation products (GDPs) are not added on purpose, but are generated during heat sterilization, especially in conventional glucose-containing solutions. Table 1. Composition of PD Solutions PD solutions contain an osmotic agent that allows a negative balance of fluids (ultrafiltration). Glucose is the most widely used osmotic agent. The only alternative osmotic agents available are 7.5% icodextrin and a 1.1% amino acid mixture (Frampton, J. E. et al.