Parenteral nutrition lipid system

Injectable lipid emulsions are used to provide parenteral nutrition and their use can be traced back to the 1920s. However, because they are particulate systems by their very nature, administration of emulsions into the blood system must be viewed with care, requiring precautions and special requirements. Indeed, until the 1950s it was not realized that one essential requirement for injectable emulsions was that the droplet diameter must be below 1 pm in diameter. Otherwise there is always a finite risk of blocking the smaller blood vessels. 

Two children developed neurological complications of fat emulsion therapy, including focal and generalized seizures, weakness, and altered mental status, before any systemic findings were in evidence (15). Biopsy and autopsy findings included cerebral endothehal and intravascular lipid deposition. These complications are potentially reversible with alteration of the parenteral nutrition content, highlighting the importance of their early recognition. 

Therefore, micelle-forming surfactant molecules (e.g., SDS) will be present in three different forms, namely, on the lipid surface, as micelles, and as monomeric surfactant molecules in solution. Lecithin will form liposomes, which have also been detected in nanoemulsions for parenteral nutrition [77], Mixed micelles have to be considered in glycocholate/lecithin-stabilized and -related systems. Micelles, mixed micelles, and liposomes are known to solubilize drugs, and are therefore attractive alternative drug-incorporation sites (especially with respect to the low incorporation capacity of lipid crystals). 

Standard AIO admixtures are used in most adults patients. However, the patients requirements regarding calories and electrolytes may vary. Dialysis patients require restricted administration of electrolytes, however patients with severe diarrhoea need a higher amount of electrolytes. Standard parenteral nutrition admixtures cannot be used in severely ill paediatric patients, neonates and premature newborns. These patients need individualised admixtures. In premature infants and newborns the all-in-two system is preferred [53]. The lipid emulsion is mixed with the vitamin combination in a separate container and either administered with the amino acid/glucose/electrolyte admixture in parallel (Y-site) or via a separate venous access. 

It is expected that intensive research will be carried out to explore original and unexpected toxicity antidote applications of fat nanoemulsions traditionally used as components of parenteral nutrition therapy. Recently, these authors reviewed the potential role of fat nanoemulsions in treatment of toxicity due to local anesthetics and other lipid-soluble drugs. Litz and coworkers [2008] reported in a 91-yr-patient the reversal of central nervous system and cardiac toxicity after local... 

Several pharmaceutical products are formulated as emulsions (1) Parenteral emulsion systems, e.g. parenteral nutritional emulsions, lipid emulsions as drug carriers (2) Perfluorochemical emulsions as artificial blood substitute (3) Emulsions as vehicles for vaccines (4) topical formulations, e.g. for treatment of some skin diseases (dermatitis). 

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