Analysis of all-in-one parenteral nutrition admixtures by liquid chromatography and laser diffraction: study of stability

All-in-one parenteral nutrition admixtures are complex lipid emulsions (oil /water) which require absolute sterility. stability and no precipitates. Pa rticle diameter must be in the range 0.4-1 mum in order to mime the size of chylomicra. Added vitamins must not degrade during infusion time (24 h). I n this study, the physicochemical stability of parenteral nutrition admixtu res was tested in the course of time at different storage temperatures. Two liquid chromatographic methods, based on solid phase extraction (SPE), wer e developed for fat-soluble vitamin determination. Stability studies were c arried out on three industrial lipid emulsions and on six compounded all-in -one admixtures. They were stored at three different temperatures: 4 degree sC (storage), 25 degreesC (compounding) and 37 degreesC (infusion); then th ey were analyzed at starting time and at 24, 48 and 72 h after compounding. Particle diameter was determined by means of Laser, Particle Sizer Analyse tte 22, which uses laser diffraction technique (light scattering - reverse Fourier optics). Fat-soluble vitamins (retinol palmitate and alpha-, delta- , gamma -tocophcrol) were determined in admixtures with a branded vitamin c ompound called Idroplurivit(R) Liofilizzato. Samples were extracted by SPE on C-18 cartridges, then they were separated by reversed-phase liquid chrom atography (LC) and detected by ultraviolet detection (retinol palmitate) an d electrochemical detection (tocopherols). Laser diffraction analysis point ed out that particle size did not change in the course of time at the teste d temperatures. LC analysis showed that vitamins interact each other and de grade after compounding at different times and storage temperatures; only r etinol palmitate is stable at 37 degreesC. Retinol palmitate recovery was 9 8%, coefficient of variation (CV) 5.4%, detection limit 25 mug/l, limit of quantitation 75 mug/l and there were not interfering substances. Tocopherol s average recovery was 99%, CV 3.5%, detection limit 15 ng/l and limit of q uantitation 50 ng/l. In conclusion, all-in-one parenteral admixtures were p roved to be physically stable under analysis conditions, but degradation of retinol palmitate and tocopherols requires admixtures with vitamins to be infused within 24 h after compounding. (C) 2001 Elsevier Science B.V. All r ights reserved.