Introduction to Thiamine

Contents 1 Pinyin 2 English reference 3 Overview 4 Discovery of thiamine 5 Source of thiamine 6 Physiological functions of thiamine 7 Diseases caused by thiamine deficiency 8 Thiamine poisoning 8.1 Clinical manifestations 8.2 Treatment 9 Medical examination of thiamine 9.1 Name of examination 9.2 Classification 9.3 Material collection 9.4 Determination principle of vitamin B1 9.5 Reagents 9.6 Operation method 9.7 Normal value 9.8 Clinical significance of test results 9.9 Notes 9.10 Related diseases 10 Vitamin B1 pharmacopoeia standard 10.1 Product name 10.1.1 Chinese name 10.1.2 Chinese Pinyin 10.1.3 English name 10.2 Structural formula 10.3 Molecular formula and molecular weight 10.4 Source (name), content (potency) 10.5 Properties 10.5.1 Absorption coefficient 10.6 Identification 10.7 Inspection 10.7.1 Acidity 10.7.2 Clarification of solution Degree and color 10.7.3 Sulfate 10.7.4 Nitrate 10.7.5 Related substances 10.7.6 Loss on drying 10.7.7 Residue on ignition 10.7.8 Iron salt 10.7.9 Heavy metal 10.7.10 Total chlorine 10.8 Content determination 10.9 Category 10.10 Storage 10.11 Preparation 10.12 Version 11 Drug instructions 11.1 Alias ??of thiamine 11.2 Foreign name 11.3 Indications 11.4 Dosage and usage 11.5 Precautions 11.6 Specifications 12 Reference 1 Pinyin

liú àn sù 2 English reference

aneurine

thiamine

thiamin

vitamine b2

b12 vitamin b2 3 Overview

Vitamin B1 (vitamin? B1), also known as thiamine (thiamine) and anti-neuritis (aneurin), is one of the B vitamins [1]. In the body, coenzymes constituting pyruvate dehydrogenase, pyruvate decarboxylase, transketolase, alpha-ketoglutarate dehydrogenase, etc. function [1].

The English abbreviation of vitamin VB1. Also known as "thiamine", "anti-inflammatory factor", and "anti-beriberi vitamin". One of the B vitamins. VB1 mainly exists in the seed coat and germ. Yeast, lean pork, rice bran, wheat bran, soybeans, etc. are rich in VB1. Vitamin B1 is resistant to oxidation, heat, and acid, but is not resistant to alkanes and can be destroyed by alkaloids at room temperature.

Catalyzed by specific enzymes in the body, VB1 can react with ATP to generate thiamine pyrophosphate (TPP). TPP is an important coenzyme for glycolysis. Therefore, when VB1 is lacking, glucose metabolism is blocked, which on the one hand leads to insufficient energy supply for nervous tissue. On the other hand, pyruvate and lactic acid produced during glucose metabolism accumulate in the blood, urine and tissues, thus causing polyneuropathy. inflammation, and affects the metabolism and function of myocardium. Patients have irritability, forgetfulness, loss of appetite, numbness of hands and feet, rough skin, muscle pain and atrophy. In severe cases, hand, foot and wrist droop, lower limb edema and heart failure can occur, which is clinically called beriberi. At the same time, VB1 can also inhibit the activity of bile esterase, so that the important neurotransmitter acetylcholine is not destroyed, thereby maintaining the normal level of nerve excitation. When VB1 is deficient, it will lead to symptoms such as slow gastrointestinal motility, insufficient secretion of digestive juices, and indigestion. VB1 deficiency is often caused by unreasonable diet (such as mainly polished rice and excessive washing), improper cooking (such as discarding rice soup when making rice, adding salt when cooking porridge, etc.), which reduces the intake of VB1 and leads to long-term fever or illness. Wasting diseases can also lead to VB1 deficiency. As early as the Sui and Tang Dynasties, my country had been using "grain peel" rich in VB1 to treat beriberi. Most of the VB1 currently used as medicine is chemically synthesized thiamine hydrochloride. In addition to treating VB1 deficiency, it is also used as an auxiliary treatment for many diseases.

There are about 25 to 30 mg of thiamine in the adult body, with higher levels in the heart, liver, kidneys and brain, but 50% of the total amount is found in muscles. The role of thiamine in the body is to participate in carbohydrate metabolism in the form of carboxylase and coenzyme of the transhydroxyaldehyde enzyme system. It is a critical material basis in material metabolism and energy metabolism. Vitamin B1 also participates in oxidative decarboxylation in the body and is necessary for branched-chain amino acid metabolism.

In addition, vitamin B1 also plays an important role in promoting appetite, normal peristalsis of the gastrointestinal tract, and secretion of digestive juices. 4 The discovery of thiamine

Beriberi was one of the two major diseases in Japan from the late 19th century to the early 20th century, along with tuberculosis. It used to be called "Edo disease". Because people were so immature, beriberi spread quickly. During the Russo-Japanese War, many people suffered from beriberi. In the past, there were two theories about the cause of beriberi: infection and poisoning. No one knew the real cause. Umetaro Suzuki studied in Germany from 1901 to 1906. After returning home, he participated in the "Provisional Investigation Meeting on Beriberi" and believed that the cause of the disease was finely milled rice. He advocated using experiments to prove that polished rice lacks a certain inorganic component, but this component is found in high amounts in rice bran.

In 1910, Umetaro Suzuki used a degreasing agent to remove the fat content of rice bran, and then used phosphoric acid added with alcohol to precipitate the main ingredients. He named the resulting substance thiamine and patented it the following year.

The question is how effective is this thiamine in treating beriberi? Doctors without any authority refused to try it. Umetaro Suzuki had no choice but to ask a doctor from a private clinic to try it. The effect was indeed good. It is said that even the seriously ill patients recovered quickly after taking it. But the doctor also said in a letter to Umetaro Suzuki that because the recovered patients also received other treatments, it is difficult to say that it was the effect of thiocolon.

For a while, it was difficult for people to accept Suzuki Umetaro's conclusion. There is such a typical example. Umetaro Suzuki later recalled: I disclosed the news that thiamine can treat beriberi at the Tokyo Chemical Society. I heard that this incident reached the ears of Dr. X, an important person in the medical field at that time. He actually said: "Suzuki thinks that rice bran can cure athlete's foot, which is boring. It's because sincerity is effective. If rice bran can cure athlete's foot, it's boring." Beriberi can also be cured by drinking urine."

A few years later, people's suspicions and prejudices were finally overcome in front of the facts. Soon thereafter, it became clear that thiamine discovered by Umetaro Suzuki and extracted from rice bran was actually vitamin B1. 5 Sources of Thiamine

Vitamin B1 mainly exists in the outer skin and germ of seeds. Yeast, lean pork, rice bran, wheat bran, soybeans, etc. are rich in vitamin B1.

Foods rich in vitamin B1 include cereals, beans, yeast, dried fruits, hard fruits, animal hearts, liver, brain, kidney, lean pork, and eggs [2].

There are about 125 to 30 mg of vitamin B in the adult body, which is mainly distributed in the heart, brain, liver, kidney, muscle tissue, etc. 50% of the total amount exists in muscles, but it cannot be stored in large quantities in the body. Excessive The ingested portion is excreted in urine [2]. 6 Physiological functions of thiamine

The main physiological function of vitamin B1 is to constitute a coenzyme of decarboxylase and participate in the metabolism of carbohydrates. Deficiency can cause beriberi. It is best not to eat polished rice and noodles for a long time to avoid vitamin B1 deficiency. [2]

Vitamin B1 is catalyzed by specific enzymes in the body. VB1 can react with ATP to generate thiamine pyrophosphate (TPP). TPP is an important coenzyme for glycolysis. Therefore, when VB1 is lacking, glucose metabolism is blocked, which on the one hand leads to insufficient energy supply for nervous tissue. On the other hand, pyruvate and lactic acid produced during glucose metabolism accumulate in the blood, urine and tissues, thus causing polyneuropathy. inflammation, and affects the metabolism and function of myocardium. Patients have irritability, forgetfulness, loss of appetite, numbness of hands and feet, rough skin, muscle pain and atrophy. In severe cases, hand, foot and wrist droop, lower limb edema and heart failure can occur, which is clinically called beriberi. At the same time, VB1 can also inhibit the activity of bile esterase, so that the important neurotransmitter acetylcholine is not destroyed, thereby maintaining the normal level of nerve excitation. When VB1 is deficient, it will lead to symptoms such as slow gastrointestinal motility, insufficient secretion of digestive juices, and indigestion. VB1 deficiency is often caused by unreasonable diet (such as mainly polished rice and excessive washing), improper cooking (such as discarding rice soup when making rice, adding salt when cooking porridge, etc.), which reduces the intake of VB1 and leads to long-term fever or illness. Wasting diseases can also lead to VB1 deficiency. As early as the Sui and Tang Dynasties, my country had been using "grain peel" rich in VB1 to treat beriberi. Most of the VB1 currently used as medicine is chemically synthesized thiamine hydrochloride. In addition to treating VB1 deficiency, it is also used as an auxiliary treatment for many diseases. 8 Thiamine poisoning

Vitamin B1 (thiamine) is a component of the flavoenzyme prosthetic group in the body. When lacking, it will affect the body's biological oxidation and cause metabolic disorders. It is used for the prevention, treatment and auxiliary treatment of vitamin B1 deficiency diseases, such as angular stomatitis, cheilitis, glossitis, conjunctivitis and scrotumitis.

It is generally taken orally, and the amount of absorption does not increase when the oral dose is increased. Injection is rarely used. [3] 8.1 Clinical manifestations

[3]

1. Occasionally, allergic reactions may occur after injection, and anaphylactic shock may occur in some cases.

2. Nausea, vomiting, abdominal pain, diarrhea, slow heartbeat, chest tightness, and even respiratory failure may occur during poisoning. Intravenous injection may cause muscle weakness and even paralysis. There may be a transient drop in blood pressure. 8.2 Treatment

The key points of treatment for vitamin B1 poisoning are [3]:

1. Antihistamines or glucocorticoids can be used for allergic patients.

2. Giving vitamin B2 or vitamin A can produce antagonistic effects.

3. People with shock can use vasopressors.

4. Symptomatic and supportive treatment. 9 Medical examination of thiamine 9.1 Examination name

Vitamin B1 9.2 Classification

Blood biochemical examination> Serum vitamin determination 9.3 Materials taken

Blood 9.4 Determination of vitamin B1 Principle

Erythrocyte transketolase (ETK) requires thiamine pyrophosphate (TPP) as a coenzyme to be active. TPP is generated by phosphorylation of thiamine in the body. Therefore, when thiamine is lacking, ETK activity decreases. If TPP is added to such red blood cells, the apo-ETK can become active ETK again and restore its function. active.

Add red blood cell hemolysate to a buffer with or without TPP, add a sufficient amount of substrate, and after a certain period of enzymatic reaction, measure the remaining amount of substrate or the amount of product produced. , calculate the enzyme activity. The percentage increase in enzyme activity caused by the addition of TPP is the TPP reaction. The TPP effect increases when the body lacks vitamin B1. According to this principle, the thiamine status of the body can be evaluated.

This method uses orcinol reagent to react with ribose, determines the enzyme activity by measuring the amount of substrate utilized, and calculates the TPP effect %.

Ribose is heated in a concentrated hydrochloric acid solution, and is dehydrated within the molecule to form furfural, which is then condensed with orcinol to form a green substance. The depth of green is proportional to the content of ribose. 9.5 Reagents

(1) Buffer (pH7.4): Dissolve 0.28g NaCl (AR), 9.25gKCl (AR), 0.299g MgSO4 (AR) and 2.73gK2HPO4 (AR) in deionized solution In water, dilute to 1000ml, adjust to pH 7.4 with 1mol/L HCl, and store at 4°C for later use.

(2) TPP stock solution: Dissolve 25mg of TPP in 25ml of the above buffer and store in the refrigerator for later use.

(3) TPP application solution: Take 1 part of the stock solution and add 8 parts of the buffer solution and mix it for immediate use.

(4) Ribose 5-phosphate sodium salt solution: Take 3.24g of ribose 5-phosphate barium salt, put it into a 100ml beaker, and add 8.5ml of 1mol/LHCl solution. Stir to dissolve, add 45ml of distilled water, mix well, pour into a centrifuge tube, wash the beaker with distilled water several times and put it into the centrifuge tube. Add 8 ml of Na2SO4 saturated aqueous solution, stir thoroughly, put it in the cold room of the refrigerator to precipitate for 15 minutes, and then centrifuge for 15 minutes (3000r/min). Pour the supernatant into a 250ml Erlenmeyer flask, and wash the residue with 20ml of distilled water each time, 3 times. After each washing and centrifugation, the supernatant was put into an Erlenmeyer flask, and the pH was adjusted to about 7.0 with 5 mol/L KOH solution, and then adjusted to 7.4 with a pH meter. If turbidity appears, filter. The total volume of liquid at this time is approximately 120ml. Accurately measure the volume of the solution, analyze the ribose content in the solution using the orcinol method, and adjust the volume so that the ribose content per milliliter is 7.0 mg. Divide this solution into several vials and store in the refrigerator.

Application solution: Dilute the above solution 20 times with buffer so that it contains 350μg ribose per ml.

(5) 75g/L trichloroacetic acid (CP).

(6) Pentose standard solution: Weigh 10 mg of D-ribose, dissolve it in 10 ml of water (1 mg/ml) as a stock solution, and store it in the refrigerator. Application solution: Take 1 ml of the stock solution and dilute it with water to 100 ml (10 μg/ml)

(7) Orcinol reagent: First weigh 1.670 g of FeCl3·6H2O, dissolve it in water, add water to 200 ml, and refrigerate for later use. Then add 30% HCl (3 parts by volume of concentrated HCl plus 1 part by volume of distilled water). Weigh 2g of orcinol, add 30ml of water, dissolve it and transfer it to a 1L volumetric flask, add the above FeCl3, 20ml of aqueous solution, and dilute to the mark with 30% HCl.

(8) 8.5g/L NaCl solution. 9.6 Operation method

Operate according to Table 1.

9.7 Normal value

0～15% Normal

15.1%～25% Biochemical deficiency of vitamin B1

>25% Severe deficiency of vitamin B1 9.8 Clinical significance of laboratory results

Elevated vitamin B1 content: overdose of oral or non-oral B1 preparations. Reduced levels: Beriberi, Wernicke's encephalopathy (cerebral beriberi syndrome), potential B1 deficiency. 9.9 Notes

(1) Before blood drawing, it is not advisable to take too many vitamin B1 medications or eat foods rich in vitamin B1, such as animal offal (liver, heart, kidney), meat, beans, Peanuts etc.

(2) Vitamin B1 urine reference value 0.17~1.70μmol/d 9.10 Related diseases

Dehydration 10 Vitamin B1 Pharmacopoeia Standard 10.1 Product name 10.1.1 Chinese name

< p> Vitamin B1 10.1.2 Chinese Pinyin

Weishengsu B1 10.1.3 English name

Vitamin B1 10.2 Structural formula 10.3 Molecular formula and molecular weight

C12H17ClN4OS·HCl ?337.27 10.4 Source (name), content (potency)

This product is 4methyl 3[(2methyl4amino5pyrimidinyl)methyl]5(2hydroxyethyl)thiazole chloride Onium hydrochloride[4]. Calculated as dry product, the content of C12H17ClN4OS·HCl shall not be less than 99.0%. 10.5 Properties

This product is white crystal or crystalline powder; it has a weak special odor and a bitter taste; the dried product quickly absorbs about 4% of moisture in the air.

This product is easily soluble in water, slightly soluble in ethanol, and insoluble in ether. 10.5.1 Absorption coefficient

Take this product, weigh it accurately, add hydrochloric acid solution (9→1000) to dissolve and quantitatively dilute it to make a solution containing about 12.5 μg per 1 ml, and measure it with UV-visible spectrophotometry (2010 edition of Pharmacopoeia, Part II, Appendix IV A), the absorbance is measured at a wavelength of 246 nm, and the absorption coefficient () is 406 to 436. 10.6 Identification

(1) Take about 5 mg of this product, add 2.5 ml of sodium hydroxide test solution to dissolve, add 0.5 ml of potassium ferricyanide test solution and 5 ml of n-butanol, and shake vigorously for 2 minutes. Leave it to separate into layers, and the alcohol layer above will show strong blue fluorescence; add acid to make it acidic, and the fluorescence will disappear; add potassium to make it alkalescent, and the fluorescence will appear again.

(2) Take an appropriate amount of this product, add water to dissolve it, evaporate it to dryness in a water bath, and dry it at 105°C for 2 hours for measurement. The infrared light absorption spectrum of this product should be consistent with the control spectrum (Figure 1205 of "Drug Infrared Spectrum Collection").

(3) Identification reaction of the aqueous solution of this product showing chloride (Appendix III of Part II of the 2010 edition of the Pharmacopoeia). 10.7 Inspection 10.7.1 Acidity

Take 0.50g of this product, add 20ml of water to dissolve it, and measure according to the law (2010 edition of Pharmacopoeia, Part II, Appendix VI H). The pH value should be 2.8 to 3.3. 10.7.2 Clarity and color of the solution

Take 1.0g of this product and add 10ml of water to dissolve it. The solution should be clear and colorless; if it develops color, compare it with the control solution (take potassium dichromate solution for colorimetry) 0.1ml, add appropriate amount of water to make it 10ml), it should not be deeper. 10.7.3 Sulfate

Take 2.0g of this product and check it according to the law (2010 edition of Pharmacopoeia, Part II, Appendix VIII B). Compared with the control solution made of 2.0ml of standard potassium sulfate solution, it should not be more concentrated (0.01 %). 10.7.4 Nitrate

Take 1.0g of this product, dissolve it in water and dilute it to 100ml. Take 1.0ml, add 4.0ml of water and 0.5ml of 10% sodium chloride solution, shake well, and add dilute indigo rouge precisely. Test solution [Take the indigo carmine test solution and dilute it with an equal amount of water. Before use, measure 1.0ml of this solution, dilute it with water to 50ml, and measure it at the wavelength of 610nm using UV-visible spectrophotometry (Appendix IV A of Part II of the 2010 edition of the Pharmacopoeia). The absorbance should be 0.3 to 0.4]1ml. Shake well, slowly add 5.0ml of sulfuric acid along the tube wall, shake immediately and slowly for 1 minute, leave it for 10 minutes, and mix with the standard potassium nitrate solution (accurately weigh 81.5mg of potassium nitrate dried to constant weight at 105°C, and place in 50ml bottle, add water to dissolve and dilute to the mark, shake well, accurately measure 5ml, put it in a 100ml measuring bottle, dilute with water to the mark, shake well. Compare with 0.50ml of the control solution prepared in the same way. , no lighter (0.25%).

10.7.5 Related substances

Take this product, weigh it accurately, dissolve it with mobile phase and dilute it to make a solution containing about 1mg per 1ml, which is used as the test solution; accurately measure 1ml and place it in 100ml In a measuring flask, dilute to the mark with mobile phase, shake well, and use it as a control solution. According to the test of high performance liquid chromatography (2010 edition of Pharmacopoeia Part 2, Appendix V D), octadecylsilane bonded silica gel was used as the filler, and methanol-acetonitrile-0.02mol/L sodium heptanesulfonate solution (containing 1% Triethylamine, adjust the pH value to 5.5 with phosphoric acid) (9:9:82) is the mobile phase, the detection wavelength is 254nm, the number of theoretical plates is not less than 2000 based on the vitamin B1 peak, and the separation between the vitamin B1 peak and the front and rear peaks All should meet the requirements. Take 20 μl of the control solution and inject it into the liquid chromatograph, and adjust the detection sensitivity so that the peak height of the main component chromatographic peak is approximately 20% of the full scale. Then accurately measure 20 μl each of the test solution and the control solution, inject them into the liquid chromatograph respectively, and record the chromatogram to 3 times the retention time of the main peak. If there are impurity peaks in the chromatogram of the test solution, the sum of the areas of each impurity peak shall not be greater than 0.5 times (0.5%) the area of ??the main peak of the control solution. 10.7.6 Weight loss on drying

Take this product and dry it to constant weight at 105℃. The weight loss shall not exceed 5.0% (2010 edition of Pharmacopoeia, Part II, Appendix VIII L). 10.7.7 Ignition residue

shall not exceed 0.1% (2010 edition of Pharmacopoeia, Part II, Appendix VIII N). 10.7.8 Iron salt

Take 1.0g of this product, add 25ml of water to dissolve it, and check according to the law (Appendix VIII G of the second part of the 2010 edition of the Pharmacopoeia). Compare it with the control solution made of 2.0ml of standard iron solution. Deeper (0.002%). 10.7.9 Heavy metals

Take 1.0g of this product, add 25ml of water to dissolve, and check according to law (2010 edition of Pharmacopoeia, Appendix VIII H, Method 1). The heavy metal content should not exceed 10 parts per million. 10.7.10 Total chlorine content

Take about 0.2g of this product, weigh it accurately, add 20ml of water to dissolve, add 2ml of dilute acetic acid and 8 to 10 drops of bromophenol blue indicator solution, and titrate with silver nitrate ( 0.1mol/L) titrate until it appears blue-purple. Each 1ml of silver nitrate titrant (0.1mol/L) is equivalent to 3.54mg of chlorine (Cl). Calculated on a dry basis, the total chlorine content should be 20.6% to 21.2%. 10.8 Content determination

Take about 0.12g of this product, weigh it accurately, add 20ml of glacial acetic acid to dissolve it with slight heat, let it cool, add 30ml of acetic anhydride, and follow the potentiometric titration method (2010 edition of Pharmacopoeia, Part II Appendix VII A), titrate with perchloric acid titrant (0.1mol/L), and correct the titration results with a blank test. Each 1ml of perchloric acid titrant (0.1mol/L) is equivalent to 16.86mg of C12H17ClN4OS·HCl. 10.9 Categories

Vitamins. 10.10 Storage

Protect from light and seal. 10.11 Preparations

(1) Vitamin B1 tablets? (2) Vitamin B1 injection 10.12 version

"Chinese Pharmacopoeia" 2010 Edition 11 Drug Instructions 11.1 Thiamine Alias ??of vitamins

Anti-beriberi vitamins; anti-neuroinflammatory vitamins; thiamine; thiamine; vitamin B1; thiamine hydrochloride; thiamine hydrochloride; vitamin B1, vitamin B1 11.2 Foreign names

Vitamin B1, Thiamine, Betalin 11.3 Indications

Used for the prevention and treatment of beriberi and auxiliary treatment of various diseases (such as systemic infection, high fever, diabetes, hyperthyroidism and pregnancy, etc.) . 11.4 Dosage and Usage

The minimum necessary daily dose for adults is 1 mg. Pregnant women and children need more due to development. Oral administration: When treating beriberi and indigestion, 10 to 30 mg can be taken once, 3 times a day, depending on the condition. Either intramuscularly or subcutaneously, 50 to 100 mg each time, once a day. This product is not suitable for intravenous injection. Human body surface area calculator BMI index calculation and evaluation Female safe period calculator Pregnancy date calculator Normal weight gain during pregnancy Safety classification of medication during pregnancy (FDA) Five elements and eight characters Adult blood pressure evaluation Body temperature level evaluation Diabetes diet recommendations Common clinical biochemistry units Conversion to basal metabolic rate Calculate sodium supplementation calculator Iron supplementation calculator Commonly used Latin abbreviations for prescription Quick check Common symbols for pharmacokinetics Quick check Effective plasma osmolarity calculator Ethanol intake calculator

Medical encyclopedia, calculate now! 11.5 Precautions

Occasionally, allergic reactions may occur during injections, and anaphylactic shock may even occur in some individuals. Therefore, injections are rarely used except in cases of urgent need for supplementation. When increasing the oral dose, there is no increase in absorption.

People with allergies need to do a skin test before use: take 0.1ml and dilute it to 1ml, then take 0.1ml for subcutaneous injection and check the reaction results 20 minutes later.

11.6 Specifications