Compound amino acids are formulated from amino acids, sugar, electrolytes, trace elements, vitamins and pH adjusters.
I. Classification of amino acids
1.Amino acids are divided into two categories according to whether they can be synthesized in the body: essential amino acids and non-essential amino acids.
Essential amino acids (EAA): amino acids that are essential to the human body (or other vertebrates) and cannot be synthesized in the body and must be supplemented by food are called essential amino acids. For adults, there are eight of these amino acids, including lysine, methionine, leucine, isoleucine, threonine, valine, tryptophan and phenylalanine. For infants, histidine is also an essential amino acid.
Nonessential amino acids (NEAA) are amino acids that can be synthesized in animals and do not require external supplementation as a source of nutrition. Generally, the amino acids that are essential in plants and microorganisms are synthesized by themselves, and these are not called non-essential amino acids. For humans the non-essential amino acids are glycine, alanine, serine, aspartic acid, glutamic acid (and its amines), proline, arginine, histidine, tyrosine, and cystine. These amino acids are synthesized from the metabolites of carbohydrates or from the carbon chains of essential amino acids, which are further introduced by amino transfer reactions to produce amino acids.
Some non-essential amino acids such as cystine and tyrosine can also save the need for methionine and phenylalanine among the essential amino acids if they are adequately supplied.
2.According to their structures, amino acids are divided into: aromatic amino acids, heterocyclic amino acids and aliphatic amino acids.
The branched chain amino acids include L-leucine, L-isoleucine and L-valine. Aromatic amino acids: phenylalanine, tryptophan, tyrosine.
The route of amino acids
The route of amino acids includes the following three aspects: first, the synthesis of various tissue proteins and enzymes and hormones, etc.; second, the conversion of deamidation to form nitrogenous and non-nitrogenous parts, the nitrogenous part eventually forms urea in the liver, the non-nitrogenous part of the oxidation and decomposition to form the final metabolic products of carbon dioxide and water and release energy, and the other part of the synthesis of sugars and fats; third, all can be transamino action The formation of new amino acids. Third, the classification of compound amino acids and the difference between compound amino acid injection (18AA)
Different diseases have different needs for amino acids, for example, the need for glutamine increases significantly in traumatic states, branched-chain amino acids should be increased in liver diseases, and essential amino acids should be provided mainly in renal dysfunction. Compound amino acid injection is divided into nutritional and therapeutic according to its function and use. Therapeutic compound amino acid is further divided into amino acid for liver disease, amino acid for kidney disease and amino acid preparation for trauma according to its special new formula and clinical use.
The difference of compound amino acids is divided into: 1, concentration; 2, nitrogen content; 3, amino acid type; 4, the ratio of essential amino acids to non-essential amino acids (EAA/NEAA), branched chain amino acids (BCAA content); 5, whether it contains glucose and xylitol; 6, inorganic salt type content, compound amino acid injection (18AA) means that it contains 18 essential and Non-essential amino acids, which can maintain the positive nitrogen balance of malnourished patients.
Third, the balanced type of supplementary nutrition
These amino acid preparations contain essential and non-essential amino acids required for human protein, and are used as the main component of parenteral nutrition drugs for patients with malnutrition caused by insufficient protein intake before and after surgery, trauma, burns, fractures and hypoproteinemia, anorexia, food refusal or food restriction.
D. Amino acid preparations for diseases
1.Amino acid preparation for kidney disease
In chronic renal failure, the plasma concentration of most essential amino acids in the body decreases, while the plasma concentration of non-essential amino acids is normal or increases. These amino acid preparations are used for parenteral nutrition support of acute and chronic renal insufficiency or renal failure caused by surgery and trauma.
2.Amino acid preparations for liver disease
The concentration of aromatic amino acids (phenylalanine, tyrosine, tryptophan) in the plasma of patients with hepatic insufficiency or hepatic coma is significantly increased, while the concentration of branched-chain amino acids (leucine, isoleucine, valine) is generally decreased, resulting in impaired synthesis of catecholamines and formation of pseudo-neurotransmitters in the brain, thus interfering with the normal function of nerve cells and causing hepatic coma. These amino acid preparations contain leucine, isoleucine and valine, these three branched chain amino acids can promote protein synthesis and inhibit protein decomposition, regulate the hepatic encephalopathy caused by amino acid metabolic disorders and pseudoneurotransmitters caused by the imbalance of the ratio of branched chain amino acids to aromatic amino acids in patients with liver disease, and are suitable for patients with acute and chronic hepatitis, liver cirrhosis and hepatic encephalopathy.
3.Amino acid preparations for trauma (stress)
These amino acid preparations correct the negative nitrogen balance, replenish protein and promote normal protein metabolism in human body, and are suitable for nutritional support of patients with large burns, trauma and severe infection and other stressful conditions such as muscle catabolism hypermetabolism, digestive system dysfunction, nutritional deterioration and immune function decline, as well as for improving the nutritional status of patients after surgery.
V. Amino acid preparations for pediatric use
Amino acids have different metabolic effects in infants and adults. The activity of phenylalanine hydroxylase and cystathionase in infants is low, which makes them prone to hyperphenylalaninemia and hypomethioninemia, and the synthesis of histidine is slow, which makes them prone to hypohistidinemia. Increase the dosage of cysteine and histidine to meet the nutritional needs of children. The amino acid injection for pediatric use (1 8AA-II) contains taurine and appropriate amounts of glutamic acid and mennitine. Infants and children with incomplete liver enzyme systems are prone to taurine deficiency, and taurine has the functions of protecting cell membranes, promoting brain development, maintaining normal retinal function, preventing cholestasis and strengthening cardiac muscle cells. These two commonly used amino acid preparations for pediatric use are used for pediatric digestive system diseases that cannot take in food from the stomach and intestines, pediatric severe trauma, burns, sepsis and other imbalances of nitrogen balance in the body, and pediatric hypoproteinemia caused by various diseases. Amino acid injection for pediatric use (18AA-I), amino acid injection for pediatric use (1 8AA-II).
VI. Notes on the use of amino acids
1, according to the patient’s condition needs to choose the compound amino acid preparation balance type, disease applicable type and pediatric use of amino acids have indications and contraindications, can not be mixed.
2. Pay attention to the drip rate of compound amino acid injection. Too fast drip rate may cause nausea, vomiting, palpitation, chest tightness, headache, etc. Usually, the balanced amino acid for nutrition is controlled at 40 drops per minute; the amino acid for liver disease does not exceed 40 drops per minute; the amino acid for kidney disease is 15 drops per minute.
3.Prevent the occurrence of phlebitis when infusing high concentration amino acids, it is better to use 5% or 10% glucose injection, where glucose injection can also reduce the osmotic pressure while providing energy needs.
4.Adjust the order of infusion of fluids, first infuse other isotonic or low concentration fluids, then infuse compound amino acids, or infuse between other fluids.
5. Pay attention to the temperature of compound amino acid injection can precipitate crystals when it is cold, when the room temperature is too low, warm up the product to close to body temperature and then use it.
6.Explain the therapeutic effect of the drug to the patient before administration. Tell the patient the reason for the fast or slow drip rate and instruct the patient not to adjust the drip rate without permission.
7.Patients using amino acids should be asked whether they are allergic to heterogeneous proteins before using amino acids, and if there is protein allergy and allergic body should be listed as contraindicated.
8, long-term infusion should have a plan to use the vein, avoid the original eye of the needle from the bottom up gradually move and alternate the rotation of use.
9, aseptic management compounded amino acid preparations are prone to multiply microorganisms, if the appearance is found to be abnormal before use, it cannot be applied, and the remaining solution after injection cannot be stored and reused.
10, total parenteral nutrition (TPN) application of all-in-one mixture of drug delivery, the actual operation of the mixing order must be strictly in accordance with the following procedures: trace elements and cationic electrolytes added to amino acids, phosphate added to glucose, the above two solutions mixed in a three-chamber bag. Water-soluble and fat-soluble vitamins are mixed and added to lipid milk. The mixture is then added to the three-chamber bag, vented and lightly shaken.