ABSTRACT
Total parenteral nutrition [TPN] replaces and maintains essential nutrients in patients in whom oral or tube feedings are contraindicated or inadequate. A nutritional assessment must be carried out before initiating TPN in order to determine nutritional needs and any metabolic changes due to the patient's underlying condition, medications or concurrent therapies. In addition to carbohydrates, proteins and fats, certain amounts of micronutirents are also added to TPN solutions. These micronutrients include electrolytes, vitamins, and trace minerals. This review highlights some basic concepts regarding the use and formulation of TPNs along with their advantages and disadvantages and the importance of water soluble vitamins B[2] and B[12] in human nutrition
ABSTRACT
Formylmethylflavin [FMF] is a major intermediate product in the aerobic and anaerobic photolysis of riboflavin [RF] and is highly sensitive to light and hydrolysis. It is more sensitive to light as compared to RF. FMF is further degraded into lumichrome [LC], carboxymethylflavin [CMF] in acidic medium, and LC, CMF and lumiflavin [LF] in alkaline medium. When FMF is exposed to light it is degraded in to LC and LF via a photoreduction and CMF through photooxidation pathways. In aerobic and anaerobic conditions, RF when exposed to light is excited to singlet state [1RF] and from singlet to triplet state [3RF]. This is followed by the conversion of 3RF into a semiquinone radical [RFH] and this radical further disproportionate to form an oxidized RF and a cyclic intermediate, which is further oxidized to FMF and degradation products [LC, LF, CMF]