Parenteral nutrition (PN), or intravenous feeding, is the feeding of nutritional products to a person intravenously, bypassing the usual process of eating and digestion. The products are made by pharmaceutical compounding entities or standard pharmaceutical companies. The person receives a nutritional mix according to a formula including glucose, salts, amino acids, lipids and vitamins and dietary minerals. It is called total parenteral nutrition (TPN) or total nutrient admixture (TNA) when no significant nutrition is obtained by other routes, and partial parenteral nutrition (PPN) when nutrition is also partially enteric. It is called peripheral parenteral nutrition (PPN) when administered through vein access in a limb rather than through a central vein as in central venous nutrition (CVN).