Composition of acetaminophen and phenacetin and application thereof

Abstract

The invention discloses a composition of acetaminophen and phenacetin and application thereof, and belongs to the technical field of medicines. In the composition of the acetaminophen and the phenacetin, the weight ratio of the acetaminophen to the phenacetin is 1: (0.1-2.5); the phenacetin can be used for inhibiting liver injury caused by acetaminophen. When the composition is used, even if the dosage of the acetaminophen is increased to a poisoning dosage or a lethal dosage, acute liver injury cannot be caused; compared with the single use of acetaminophen or phenacetin with the same dosage, the antipyretic and analgesic effects of acetaminophen or phenacetin are enhanced. The composition and opioid central analgesic form a compound preparation, and the analgesic effect of the compound preparation can be obviously enhanced. The composition and a plurality of Chinese herbal medicine effective components with the effects of clearing heat, detoxifying and resisting inflammation form a compound preparation, so that the hepatotoxicity of acetaminophen can be effectively prevented, and the antipyretic, analgesic and anti-inflammatory effects of acetaminophen can be enhanced.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical technology, specifically relating to the composition of acetaminophen and phenacetin and its application. Background Technology

[0002] Acetaminophen (Formula I), also known as paracetamol, is one of the best-selling antipyretic analgesics. It is typically formulated alone or in combination with other drugs, such as opioid centrally acting analgesics, into various oral or injectable formulations for the treatment of various acute and chronic pain. However, high doses of acetaminophen can cause severe liver damage, even leading to acute liver failure and death; this adverse reaction often has serious consequences. Previous studies have found that the hepatotoxicity of acetaminophen originates from its metabolite N-acetyl-p-benzo-quinoneimine (NAPQI), a reaction primarily catalyzed by hepatic cytochrome P450 2E1.

[0003]

[0004] Acute hepatotoxicity caused by acetaminophen is a major concern for both medicinal chemists and clinical medical professionals. Currently, only acetylcysteine ​​is approved for clinical treatment of acute hepatotoxicity caused by acetaminophen; its efficacy is limited within the window period. There are two types of drug administration strategies under development. One is the pretreatment strategy. For example, the applicant's previous research found that many traditional Chinese medicines with "heat-clearing, detoxifying, and anti-inflammatory" effects can effectively prevent and treat hepatotoxicity caused by acetaminophen when administered before the onset of liver damage. In particular, the combined use of matrine and glycyrrhizic acid can significantly protect the liver from damage caused by high doses of acetaminophen (CN1286464C; Chem Biol Interact. 2009;181(1): 15-19). Another approach is post-treatment. For example, in 2020, the journal *SciTransl Med.* (2020; 12(535): eaav8075) reported that heparan sulfate was effective in treating acute acetaminophen-induced liver injury in mice. Another example is the applicant's team's research, which showed significant efficacy in treating acetaminophen-induced liver injury in mice with 18-β-glycyrrhizin, the main active ingredient in licorice (Exper Biol Med. 2020 Dec 20;1535370220977823. doi: 10.1177 / 1535370220977823.). Unfortunately, both of these current prevention and treatment strategies still have significant limitations. Pre-treatment strategies involve preventative treatment before acetaminophen-induced liver toxicity occurs, which has limited clinical value because it is impossible to know in advance who will develop acetaminophen-induced liver toxicity, making targeted preventative treatment impossible. The current post-treatment strategy involves treating acetaminophen-induced hepatotoxicity, but this approach is costly, has limited efficacy, and suffers from a persistently high mortality rate and poor prognosis. Therefore, an effective method to prevent acetaminophen-induced hepatotoxicity is needed.

[0005] Phenacetin (Formula II) has been withdrawn from the market as a single antipyretic and analgesic because daily doses exceeding one gram for more than three years may cause kidney damage and an increased incidence of urinary tract cancers (Hinson, Environmental Health Perspectives, 1983;49:71-79). Furthermore, high doses of phenacetin can lead to methemoglobinemia. However, in some regions, phenacetin remains an effective ingredient in various compound preparations for antipyretic and analgesic purposes. For example, compound aspirin tablets consist of aspirin, phenacetin, and caffeine (Chen Xinqian et al., New Pharmacology (18th Edition), 2018, p. 245). Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the present invention aims to provide a composition of acetaminophen and phenacetin and its application thereto, so as to solve the technical problem that existing treatment methods cannot effectively prevent the occurrence of acetaminophen liver toxicity.

[0007] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides a composition of acetaminophen and phenacetin, comprising acetaminophen and phenacetin; said phenacetin is capable of inhibiting liver damage induced by acetaminophen.

[0008] Preferably, the weight ratio of acetaminophen to phenacetin is 1:(0.1~2.5).

[0009] Preferably, the dosage form of the composition is an oral formulation or an injectable formulation.

[0010] A second aspect of the invention provides the use of a composition of acetaminophen and phenacetin in the preparation of an antipyretic and analgesic drugs.

[0011] A third aspect of the invention provides the use of a composition of acetaminophen and phenacetin in the preparation of a nonspecific anti-inflammatory drug.

[0012] A fourth aspect of the invention provides the use of a composition of acetaminophen and phenacetin in the preparation of a centrally acting analgesic.

[0013] A fifth aspect of the invention provides an anti-inflammatory composition comprising a triterpenoid saponin compound and the above-described composition of acetaminophen and phenacetin.

[0014] Preferably, the triterpenoid saponin compound is glycyrrhizin.

[0015] A sixth aspect of the invention provides an analgesic composition comprising an opioid analgesic and the above-described composition of acetaminophen and phenacetin.

[0016] Preferably, the opioid analgesic is oxycodone.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The acetaminophen and phenacetin combination provided by this invention can effectively prevent hepatotoxicity caused by acetaminophen. Experiments have shown that when using the acetaminophen and phenacetin combination, even when the dose of acetaminophen is increased to a toxic or lethal dose, it will not cause acute liver damage. Moreover, compared with the use of the same dose of acetaminophen or phenacetin alone, it has enhanced the antipyretic and analgesic effects of acetaminophen or phenacetin. Specifically: (1) When a large dose of acetaminophen (900 mg / kg) is used alone, all mice develop severe hepatotoxicity, and the mortality rate is 100% within 24 hours; while when the combination of acetaminophen and phenacetin (acetaminophen is also 900 mg / kg) is given, none of the mice develop hepatotoxicity, and none die within 24 hours. At the same time, when acetaminophen 900 mg + phenacetin 300 mg (acetaminophen: phenacetin = 3:1), phenacetin can completely block the hepatotoxicity of acetaminophen. In clinical practice, the daily dose of acetaminophen for adults should not exceed 3 g. If acetaminophen and phenacetin are combined to prepare a clinical treatment drug, the daily dose of phenacetin will not exceed 1 g. This result indicates that the combination of acetaminophen and phenacetin has good clinical application value. (2) When acetaminophen and phenacetin are mixed at a subthreshold dose, a very obvious antipyretic and analgesic effect is observed. (3) When the combination of acetaminophen and phenacetin is combined with opioid central analgesics to form a compound preparation, its analgesic effect can be significantly enhanced. (4) When the combination of acetaminophen and phenacetin is combined with many Chinese herbal medicines with the effects of "clearing heat, detoxifying, and anti-inflammatory" to form a compound preparation, it can not only effectively prevent the occurrence of acetaminophen hepatotoxicity, but also enhance its antipyretic, analgesic, and anti-inflammatory effects. Attached Figure Description

[0018] Figure 1 The image shows the results of histopathological examination of mouse liver tissue (HE staining, 100x magnification) according to the present invention. Detailed Implementation

[0019] To enable those skilled in the art to understand the features and effects of the present invention, the following descriptions and definitions are only general descriptions of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in the event of any conflict, the definitions in this specification shall prevail.

[0020] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0021] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0022] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0023] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0024] Through repeated and extensive experimental research, the applicant team discovered that when phenacetin, a prodrug of acetaminophen, undergoes deethylation at the oxygen site to generate acetaminophen under the mediation of hepatic cytochrome P450 1A2 enzyme, it can inhibit the activity of P450 reductase, the chaperone molecule of P450 2E1 enzyme, thereby blocking the formation of NAPQI, the oxidized metabolite of acetaminophen.

[0025] Based on the above research, the present invention provides a composition of acetaminophen and phenacetin, comprising acetaminophen and phenacetin in a weight ratio of 1:(0.1~2.5), wherein the phenacetin is capable of inhibiting liver damage caused by acetaminophen.

[0026] The present invention also provides the use of a composition of acetaminophen and phenacetin in the preparation of antipyretic analgesics, nonspecific anti-inflammatory drugs or centrally acting analgesics.

[0027] Unless otherwise specified, the term "composition" is used interchangeably with "pharmaceutical composition" which contains an effective amount of acetaminophen, phenacetin, and optionally a pharmaceutically acceptable carrier or excipient.

[0028] Unless otherwise specified, the term "subject" may also refer to "patient," "user" of the acetaminophen and phenacetin combination, etc., and may refer to animals, especially mammals, such as humans, dogs, monkeys, cattle, horses, etc., that receive the acetaminophen and phenacetin combination of the present invention to prevent and / or treat the diseases of the present invention.

[0029] Unless otherwise specified, the term "dosage form" is also referred to as "formulation," "pharmaceutical," or "pharmaceutical preparation." According to the present invention, the term "unit-dose formulation" is also referred to as "unit-dose form," for example, referring to a single tablet, a single capsule, etc., which provides, for example, 1 / 3, 1 / 2, 1, or 2 daily doses. For example, for tablets, it is preferred that one tablet contains a daily dose; furthermore, one tablet may contain a daily dose for two days, for example, by making a notch in the middle of the tablet to allow the user to divide it in half. For heavier individuals or those who tolerate the drug, one tablet can be used daily, while for users for whom half a tablet is effective, half a tablet can be used daily.

[0030] This invention provides a composition comprising acetaminophen and phenacetin formulated with one or more non-toxic, pharmaceutically acceptable carriers. The pharmaceutical composition may be specifically formulated for oral or rectal administration in solid or liquid form, or for injection. For example, the acetaminophen and phenacetin composition may be formulated with at least one inert pharmaceutically acceptable excipient or carrier into tablets, capsules, pills, powders, granules, or other oral formulations; the acetaminophen and phenacetin composition may be formulated with other drugs, adding at least one inert pharmaceutically acceptable excipient or carrier, into a compound oral formulation with antipyretic and analgesic effects; the acetaminophen and phenacetin composition may be formulated with opioid centrally acting analgesics or other analgesics, adding at least one inert pharmaceutically acceptable excipient or carrier, into a compound oral formulation with analgesic effects; the pharmaceutically acceptable excipient or carrier may be such as sodium citrate or dihydrogen phosphate. Calcium and / or mixtures of the following substances: a) fillers or extenders such as starch, lactose, sucrose, glucose, mannitol, and silica; b) binders such as carboxymethyl cellulose, alginate, gelatin, polyvinylpyrrolidone, sucrose, and gum arabic; c) humectants such as glycerin; d) disintegrants such as agar, calcium carbonate, potato or cassava starch, alginate, certain silicates, and sodium carbonate; e) solution blockers such as paraffin; f) absorption accelerators such as quaternary ammonium compounds; g) humectants such as cetyl alcohol and glyceryl monostearate; h) adsorbents such as kaolin and bentonite; i) lubricants such as talc, calcium stearate, magnesium stearate, solid polyethylene glycol, sodium dodecyl sulfate, and mixtures thereof. For example, a combination of acetaminophen and phenacetin can be prepared with at least one inert pharmaceutically acceptable excipient or carrier to form an injectable preparation with antipyretic and analgesic effects; a combination of acetaminophen and phenacetin can be prepared with other drugs to form a compound injectable preparation with antipyretic and analgesic effects; a combination of acetaminophen and phenacetin can be prepared with opioid centrally acting analgesics or other analgesics to form a compound injectable preparation with analgesic effects. In addition to the active compound, the injectable preparation may also contain inert diluents commonly used in the art, such as water or other solvents, solubilizers and emulsifiers such as ethanol, isopropanol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butanediol, dimethylformamide, oils (especially cottonseed oil, peanut oil, corn oil, germ oil, olive oil, castor oil, and sesame oil), glycerin, tetrahydrofuranol, polyethylene glycol, and fatty acid esters of sorbitol, and mixtures thereof.

[0031] In this article, "room temperature" is usually 20℃~33℃, for example, it can be 25℃~30℃, specifically 20℃, 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, 28℃, 29℃, 30℃, 31℃, 32℃ or 33℃.

[0032] In this article, the word “including” is used to mean “including but not limited to”.

[0033] Unless otherwise specified, "%" in this article refers to weight percentage.

[0034] Unless otherwise specified, the term "effective dose" refers to the target dose that can achieve the prevention and / or treatment of the disease described in this invention in a subject.

[0035] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are merely examples of using the composition of acetaminophen and phenacetin to prepare antipyretic analgesics, preparing compound preparations with antipyretic, analgesic, and anti-inflammatory effects from traditional Chinese medicine active ingredients with "heat-clearing, detoxifying, and anti-inflammatory" effects, and preparing compound analgesics with centrally acting analgesics such as opioids, and are not intended to limit the scope of protection of the claims. Furthermore, it should be understood that after reading the description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0036] The following examples use conventional instruments and equipment in the art. The acetaminophen used is acetaminophen powder purchased from Sigma-Aldrich, catalog number Cat. # A5000; The phenacetin powder used was purchased from Sigma-Aldrich, catalog number Cat. # 77440; All other raw materials and reagents used, unless otherwise specified, are conventional commercially available products of standard specifications in the art, or can be prepared or formulated by known methods or reagent instructions. Experimental methods in the following examples, unless otherwise specified, are generally performed under standard conditions or as recommended by the manufacturer.

[0037] Example 1: Study on the hepatotoxicity and dose-effect relationship of the combination of acetaminophen and phenacetin I. Background / Purpose Phenacetin is a prodrug of acetaminophen. After administration, 60%–80% is metabolized into acetaminophen, which exerts antipyretic and analgesic effects. Numerous experimental studies have shown that in mice, ≥200 mg / kg of acetaminophen can cause severe liver damage, manifested as elevated blood alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, and necrosis of central lobe hepatocytes; its lethal dose is 700–900 mg / kg. This example studies the hepatotoxicity of a combination of acetaminophen and phenacetin and its dose-effect relationship.

[0038] II. Methods 1. Hepatotoxicity and its dose-effect relationship test 1) Preparation of a 1% acetaminophen solution: Accurately weigh 1 g of acetaminophen powder and place it in an Erlenmeyer flask containing a mixed solution of 40 mL PEG-400, 5 mL Tween-80, and 40 mL 0.9% NaCl (before adding acetaminophen, place it in a 40°C constant temperature water bath and stir thoroughly to ensure uniform mixing). While stirring continuously, slowly add acetaminophen to the mixture, then transfer the mixed solution to a 100 mL volumetric flask and dilute to 100 mL with 0.9% NaCl to obtain a 1% (w / v) acetaminophen solution.

[0039] 2) Preparation of a combination solution of acetaminophen and phenacetin: Accurately weigh 1 g of acetaminophen powder and 0.1 g of phenacetin powder, and place them in an Erlenmeyer flask containing a mixed solution of 40 mL of PEG-400, 5 mL of Tween-80, and 40 mL of 0.9% NaCl (before adding acetaminophen and phenacetin, keep the mixture in a constant temperature water bath at 40°C and stir thoroughly to ensure homogeneity). While stirring continuously, slowly add acetaminophen and phenacetin to the mixture, and then transfer the mixed solution to a 100 mL volumetric flask and make up to 100 mL with 0.9% NaCl to obtain a combination solution of 1% (w / v) acetaminophen and 0.1% (w / v) phenacetin. In the same way, prepare a combination solution of 1% (w / v) acetaminophen and 0.5% (w / v) phenacetin and a combination solution of 1% (w / v) acetaminophen and 2.5% (w / v) phenacetin, respectively.

[0040] 3) Kunming mice (male, 23-28 g, 4-6 weeks old) were randomly divided into groups A-E, fed in a standardized manner, and fasted for 12 hours before the experiment.

[0041] Group A: Normal control (n = 8), intraperitoneal injection of an equal volume of mixed solution (40 mL PEG-400 and 5 mL Tween-80 diluted to 100 mL with 0.9% NaCl); Group B: Acetaminophen 200 mg / kg, intraperitoneal injection of a 1% (w / v) acetaminophen mixed solution (n = 10). Group C: Acetaminophen 200 mg / kg + Phenacetin 20 mg / kg, intraperitoneal injection of a mixture of 1% (w / v) acetaminophen and 0.1% (w / v) phenacetin (n = 10). Group D: Acetaminophen 200 mg / kg + phenacetin 100 mg / kg, intraperitoneal injection of a mixture of 1% (w / v) acetaminophen and 0.5% (w / v) phenacetin (n = 10). Group E: Acetaminophen 200 mg / kg + Phenacetin 500 mg / kg, intraperitoneal injection of a mixture of 1% (w / v) acetaminophen and 2.5% (w / v) phenacetin (n = 10). Mice were injected intraperitoneally with the corresponding drugs according to the above groupings. Blood samples were collected 24 hours later, and serum ALT and AST levels were measured in each group using a Hitachi automated biochemical analyzer. The livers were then dissected, and left lobe liver tissue was taken for histopathological examination (H&E staining). The pathological changes in the liver tissue were evaluated using a two-person blind method.

[0042] 2. Survival rate trial 1) Preparation of 4.5% acetaminophen solution: Accurately weigh 4.5 g of acetaminophen powder and place it in an Erlenmeyer flask containing a mixed solution of 40 mL PEG-400, 5 mL Tween-80 and 40 mL 0.9% NaCl. Under constant temperature water bath and continuous stirring, slowly add acetaminophen to the mixture. Then transfer the mixed solution to a 100 mL volumetric flask and make up to 100 mL with 0.9% NaCl to obtain a 4.5% (w / v) acetaminophen mixed solution.

[0043] 2) Preparation of a combination solution of acetaminophen and phenacetin: Accurately weigh 4.5 g of acetaminophen powder and 1.5 g of phenacetin, and place them in an Erlenmeyer flask containing a mixed solution of 40 mL of PEG-400, 5 mL of Tween-80 and 40 mL of 0.9% NaCl. Under constant temperature water bath and continuous stirring, slowly add acetaminophen and phenacetin to the mixture. Then transfer the mixed solution to a 100 mL volumetric flask and make up to 100 mL with 0.9% NaCl to obtain a combination solution of acetaminophen (4.5% (w / v)) and phenacetin (1.5% (w / v)).

[0044] 3) Twenty-four Kunming mice (male, 23-28 g, 4-6 weeks old) were randomly divided into three groups and fed in a standardized manner. They were fasted for 12 hours before the experiment.

[0045] Group I: Normal control (n = 4), intraperitoneal injection of an equal volume of mixed solution (40 mL PEG-400 and 5 mL Tween-80 diluted to 100 mL with 0.9% NaCl); Group II: Acetaminophen 900 mg / kg, intraperitoneal injection of acetaminophen (4.5% (w / v)) mixed solution (n=10); Group III: Acetaminophen 900 mg / kg + phenacetin 300 mg / kg, intraperitoneal injection of a mixed solution of acetaminophen (4.5% (w / v)) and phenacetin (1.5% (w / v)) (n = 10); Mice were injected intraperitoneally with the corresponding drugs according to the above grouping, and the survival rate of mice in each group was observed at 24 h.

[0046] III. Results 1. The results of the hepatotoxicity and dose-effect relationship test of the combination of acetaminophen and phenacetin are shown in Table 1. The histopathological examination results of the liver tissue of mice in each group are as follows: Figure 1 As shown, when the dose of acetaminophen is 200 mg / kg and the weight ratio of acetaminophen to phenacetin is 1:(0.1~2.5), phenacetin can significantly inhibit the hepatotoxicity induced by acetaminophen, and this effect is dose-dependent.

[0047] Table 1. The inhibitory effect of phenacetin on the hepatotoxicity of acetaminophen and its dose-effect relationship ( ±SD)

[0048] Compared with Group B, P Less than 0.05, **compared to group B, P Less than 0.01; # Compared with Group A, P Greater than 0.05.

[0049] 2. The 24-hour survival rate test results in mice showed that all mice injected intraperitoneally with acetaminophen 900 mg / kg + phenacetin 300 mg / kg (acetaminophen:phenacetin = 1:0.33) survived within 24 hours, with no deaths. However, all mice in the acetaminophen 900 mg / kg group died within 24 hours. This result indicates that the addition of phenacetin can prevent acetaminophen-induced liver toxicity when used at high doses.

[0050] Example 2: Study on the analgesic effect of a combination of acetaminophen and phenacetin I. Background / Purpose After discovering that phenacetin can significantly inhibit the hepatotoxicity of acetaminophen, we investigated whether there was a synergistic effect between phenacetin and acetaminophen in their analgesic effects.

[0051] II. Methods 1. Prepare a 0.5% acetaminophen solution: Add 20 mL of ethanol to a 50 mL beaker, then add 0.5 g of weighed acetaminophen, and place it in an ultrasonic cleaner for 5-10 min to sonicate it completely. Transfer the solution to a 100 mL volumetric flask and dilute to 100 mL with 0.9% NaCl.

[0052] 2. Preparation of a 0.59% phenacetin solution: Pour 20 mL of ethanol into a 50 mL beaker, add 0.59 g of accurately weighed phenacetin powder, and place the beaker in an ultrasonic cleaner and sonicate for 5-10 min to completely dissolve the phenacetin. Then transfer the solution to a 100 mL volumetric flask, add 0.9% sodium chloride solution and bring the volume to 100 mL to obtain a 0.59% (w / v) phenacetin solution.

[0053] 3. Preparation of a solution of acetaminophen and phenacetin: Following the methods described in "1 and 2" above, prepare a solution of a 0.5% (w / v) acetaminophen and 0.59% (w / v) phenacetin composition (0.9% NaCl containing 20% ​​(v / v) ethanol).

[0054] 4. Kunming mice (male, 23-28 g, 4-6 weeks old) were randomly divided into groups, acclimatized to the environment for 7 days, given free access to water, and under standard lighting. They were fasted for 12 hours before the experiment.

[0055] Group A: Normal control (n = 4), administered an equal volume of solution (0.9% NaCl containing 20% ​​(v / v) ethanol) by gavage. Group B: Negative control (n = 10), administered an equal volume of solution (0.9% NaCl containing 20% ​​(v / v) ethanol) by gavage. Group C: Phenacetin 118 mg / kg was administered via gavage in a 0.59% (w / v) phenacetin solution (n = 10). Group D: 100 mg / kg of acetaminophen was administered by gavage with a 0.5% acetaminophen solution (n = 10). Group E: Acetaminophen 100 mg / kg + phenacetin 118 mg / kg were administered by gavage with a combination solution of 0.5% (w / v) acetaminophen and 0.59% (w / v) phenacetin (n = 10).

[0056] Thirty minutes after administering the above-mentioned drugs to mice in each group, mice in groups B, C, D, and E were intraperitoneally injected with 0.6% glacial acetic acid (10 mL / kg). Five minutes later, the mice in each group were placed in glass dishes, and the number of abdominal muscle contractions, writhing movements, and hind limb extensions were recorded for each group from 5 to 20 minutes. The inhibition rate was calculated using the following formula: Inhibition rate (%) = [(Number of writhing movements in negative control group mice - Number of writhing movements in treatment group mice) / Number of writhing movements in negative control group mice] × 100%.

[0057] III. Results Table 2. Experimental results of the synergistic analgesic effect of phenacetin and acetaminophen ( ±SD)

[0058] Rank-sum test, compared with group B, * P Less than 0.05, ** P Less than 0.01.

[0059] The results of the analgesic effect experiment are shown in Table 2. The results showed that in a mouse model of nociceptive pain induced by intraperitoneal injection of 0.6% glacial acetic acid, treatment with phenacetin 118 mg / kg via gavage resulted in an average pain inhibition rate of 21.5%, but this was not statistically significant. Treatment with acetaminophen 100 mg / kg via gavage resulted in an average pain inhibition rate of 39.4%, which was statistically significant. However, treatment with acetaminophen 100 mg / kg + phenacetin 118 mg / kg via gavage resulted in a pain inhibition rate as high as 55.6%, which was highly statistically significant. This result indicates that acetaminophen and phenacetin can synergistically inhibit nociceptive pain induced by 0.6% glacial acetic acid in mice, suggesting that the oral combination of acetaminophen and phenacetin enhances the analgesic effect of either acetaminophen or phenacetin alone.

[0060] Example 3: Study on the antipyretic effect of the combination of acetaminophen and phenacetin I. Background / Purpose Phenacetin, as a prodrug of acetaminophen, can inhibit the hepatotoxicity of acetaminophen. Mice orally administered a combination of acetaminophen and phenacetin showed significantly better inhibition of acetic acid-induced nociceptive pain compared to mice orally administered acetaminophen alone. The purpose of this example is to investigate whether phenacetin can enhance the antipyretic effect of acetaminophen.

[0061] II. Methods Fifty-eight male Wistar rats (weighing 180–220 g) were acclimatized to their environment for one week, with free access to water and standard lighting. Before the experiment, body temperature was measured daily from 9:00 to 11:00 AM (sensor probe inserted 2 cm into the anus) for three consecutive days. Fifty rats with a body temperature ranging from 36.6–38.0℃ and a temperature variation not exceeding 0.3℃ were selected and randomly divided into groups of 10.

[0062] Group A: Normal control group, administered an equal volume of solution (0.9% NaCl containing 20% ​​(v / v) ethanol) by gavage. Group B: Negative control, administered an equal volume of solution (0.9% NaCl containing 20% ​​(v / v) ethanol) by gavage. Group C: Phenacetin 59 mg / kg was administered via gavage in a 0.59% (w / v) phenacetin solution; Group D: Administered acetaminophen 50 mg / kg by gavage with a 0.5% acetaminophen solution; Group E: Acetaminophen 50 mg / kg + phenacetin 59 mg / kg were administered by gavage with a combination solution of 0.5% (w / v) acetaminophen and 0.59% (w / v) phenacetin.

[0063] One hour after each group of rats was administered the corresponding drug via gavage, rats in groups B, C, D, and E were subcutaneously injected with 20% yeast suspension (10 mL / kg) in the back to induce fever. Two hours after fever induction, rectal temperature was measured again for statistical analysis and intergroup comparisons.

[0064] III. Results Table 3. Experimental results of the synergistic antipyretic effect of phenacetin and acetaminophen ( ±SD)

[0065] Compared to Group B, * P Less than 0.05.

[0066] The results of the antipyretic effect are shown in Table 3. The results indicated that in a rat fever model induced by 20% yeast suspension (10 mL / kg), treatment with acetaminophen 50 mg / kg or an equimolar concentration of phenacetin (59 mg / kg) via gavage did not show statistically significant differences in antipyretic effect compared to the negative control group. However, treatment with acetaminophen 50 mg / kg + phenacetin 59 mg / kg via gavage resulted in a statistically significant difference in body temperature change compared to the negative control group. This result indicates that acetaminophen and phenacetin can synergistically inhibit yeast suspension-induced fever in rats, suggesting that oral administration of the combination of acetaminophen and phenacetin significantly enhances the antipyretic effect of either acetaminophen or phenacetin alone.

[0067] Example 4: Study on the enhancement of the anti-inflammatory effect of glycyrrhizin by the combination of acetaminophen and phenacetin I. Background / Purpose Unlike aspirin and ibuprofen, phenacetin and acetaminophen have relatively weak anti-inflammatory effects among nonsteroidal antipyretics (NSAIDs). This undoubtedly greatly limits the use of combinations of acetaminophen and phenacetin. Clinically, many traditional Chinese medicines with heat-clearing, detoxifying, and anti-inflammatory effects not only have slow onset of action but also unsatisfactory anti-inflammatory effects. Glycyrrhizin is the main active ingredient of the traditional Chinese medicine licorice. Chemically, it belongs to the triterpenoid class of compounds and has certain non-specific anti-inflammatory effects. This example uses mouse ear swelling experiments and mouse peritoneal capillary permeability experiments to study whether the combination of acetaminophen and phenacetin can enhance the anti-inflammatory effect of the active ingredient glycyrrhizin in traditional Chinese medicine.

[0068] II. Methods Mouse ear swelling test and mouse peritoneal capillary permeability test are commonly used methods to study the non-specific anti-inflammatory effects of chemical drugs and active ingredients of traditional Chinese medicine. In particular, the combination of the two can better reflect the effect of drugs on changes in the permeability of surface and deep capillaries.

[0069] 1. Mouse ear swelling experiment 1) Preparation of a mixed aqueous solution of acetaminophen, phenacetin and glycyrrhizin: Accurately weigh 0.5 g of acetaminophen powder, 0.59 g of phenacetin powder and 0.4 g of glycyrrhizin powder. Pour 20 mL of ethanol into a 50 mL beaker. First, add the weighed 0.5 g of acetaminophen and place it in an ultrasonic cleaner and sonicate for 5-10 min to completely dissolve it. Then add 0.59 g of phenacetin and sonicate for 5-10 min to completely dissolve it. Transfer the solution to a 100 mL volumetric flask. 0.4 g glycyrrhizin was placed in a 25 mL beaker and dissolved in 10 mL of 0.9% NaCl. The solution was then transferred to the volumetric flask containing 0.5 g acetaminophen and 0.59 g phenacetin and diluted to 100 mL with 0.9% NaCl to obtain a mixed solution of acetaminophen (0.5% (w / v)), phenacetin (0.59% (w / v)) and glycyrrhizin (0.4% (w / v)).

[0070] 2) Kunming mice (male, 23-28 g, 4-6 weeks old), acclimatized to the environment for 7 days, with free access to water, standard lighting, and fasted for 12 hours before the experiment. Randomized into groups of 10 mice each.

[0071] Group A: Negative control, administered by gavage an equal volume of a mixed solution (0.9% NaCl containing 20% ​​(v / v) ethanol). Group B: Acetaminophen 100 mg / kg + phenacetin 118 mg / kg was administered by gavage with a combination solution of 0.5% (w / v) acetaminophen and 0.59% (w / v) phenacetin. Group C: Positive control I, administered 80 mg / kg of glycyrrhizin solution by gavage; Group D: Acetaminophen 100 mg / kg + phenacetin 118 mg / kg + glycyrrhizin 80 mg / kg were administered by gavage in a mixed solution of acetaminophen (0.5% (w / v)), phenacetin (0.59% (w / v)) and glycyrrhizin (0.4% (w / v)). Group E: Positive control II, administered 30 mg / kg prednisone acetate by gavage.

[0072] The mice were administered the corresponding drugs via gavage according to the above groups, once a day for four consecutive days. Thirty minutes after the fourth administration of the corresponding drug, 25 μL of xylene was evenly applied to both sides of the right ear of each group to induce inflammation. The animals were sacrificed 0.5 h later, and ear patches were punched out at the same location on both ears using an 8 mm diameter punch. The patches were weighed using an electronic balance, and the degree of swelling and the swelling inhibition rate were calculated according to the following formula.

[0073] Swelling degree = Right earpiece mass Left earpiece quality; Swelling inhibition rate (%) = [(mean ear swelling degree of negative control group)] [Mean ear swelling in the treatment group / Mean ear swelling in the negative control group] × 100%.

[0074] 2. Mouse capillary permeability test Kunming mice (male, 23-28 g, 4-6 weeks old) were acclimatized to the environment for 7 days, given free access to water, and under standard lighting conditions. They were fasted for 12 hours before the experiment. They were randomly divided into groups of 10 mice each.

[0075] Group A: This group served as the control group and was given an equal volume of solution by gavage. Group B: Acetaminophen 100 mg / kg + phenacetin 118 mg / kg were administered by gavage; Group C: Glycyrrhizin 80 mg / kg was administered by gavage; Group D: The patient was given a mixed solution of acetaminophen (0.5% (w / v)), phenacetin (0.59% (w / v)) and glycyrrhizin (0.4% (w / v)) by gavage. The dosage was acetaminophen 100 mg / kg + phenacetin 118 mg / kg + glycyrrhizin 80 mg / kg. Group E: Positive control, administered an equal volume of prednisolone acetate by gavage at a dose of 30 mg / kg.

[0076] Mice in each group were administered the corresponding drugs via gavage once daily for four consecutive days. Thirty minutes after the fourth gavage administration, 0.5% Evans blue solution (10 mL / kg) was injected via the tail vein, and simultaneously, 0.6% glacial acetic acid (10 mL / kg) was injected intraperitoneally. Twenty minutes later, the mice were sacrificed, and 5 mL of 0.9% NaCl was injected intraperitoneally. The abdomen was gently massaged for 1 minute, the peritoneal cavity was opened, and the fluid was aspirated. The solution was centrifuged at 3000 r / min for 15 minutes, and the supernatant was collected. The absorbance (A) of the supernatant was measured at 590 nm using a UV spectrophotometer.

[0077] III. Results Table 4 Results of mouse ear swelling test ( ±SD)

[0078] Compared with the control group, ** P Less than 0.01.

[0079] Table 5 Effects on peritoneal capillary permeability in mice ( ±SD)

[0080] Compared with the control group, * PLess than 0.05.

[0081] The results of the mouse ear swelling experiment are shown in Table 4, and the results of the mouse peritoneal capillary permeability experiment are shown in Table 5. The results indicate that although glycyrrhizin, an effective extract of licorice, has certain non-specific anti-inflammatory effects, its efficacy is limited with low-dose, short-term use. However, the combined administration of glycyrrhizin with a combination of acetaminophen and phenacetin significantly enhanced the anti-inflammatory effect of glycyrrhizin, suggesting that combining the combination of acetaminophen and phenacetin with triterpenoid active ingredients from traditional Chinese medicine can achieve satisfactory anti-inflammatory effects.

[0082] Example 5: Effect of the combination of acetaminophen and phenacetin on the analgesic effect of the centrally acting analgesic oxycodone I. Background / Purpose Having demonstrated that the combination of acetaminophen and phenacetin possesses antipyretic and analgesic effects, as well as enhances the nonspecific anti-inflammatory effects of traditional Chinese medicine for clearing heat and detoxifying, we further investigated the effect of the acetaminophen and phenacetin combination on the analgesic effect of the centrally acting analgesic oxycodone. This example uses a rat model of neuropathic pain to study whether the combination of acetaminophen and phenacetin can enhance the analgesic effect of the centrally acting analgesic oxycodone.

[0083] II. Methods The rat neuropathic pain model is a classic method for studying centrally acting analgesics. This embodiment uses this model to study the effect of the combination of acetaminophen and phenacetin on the analgesic effect of the centrally acting analgesic oxycodone, using the rats' responses to mechanical and thermal pain as indicators.

[0084] 1. Preparation of a mixed aqueous solution of acetaminophen, phenacetin, and oxycodone: Accurately weigh 0.5 g of acetaminophen powder, 0.59 g of phenacetin powder, and 0.4 g of oxycodone powder. Pour 20 mL of ethanol into a 50 mL beaker. First, add the weighed 0.5 g of acetaminophen and sonicate in an ultrasonic cleaner for 5-10 min until completely dissolved. Then add 0.59 g of phenacetin and sonicate for 5-10 min until completely dissolved. Transfer the solution to a 100 mL volumetric flask. 0.4 g of oxycodone was placed in a 25 mL beaker and dissolved in 10 mL of 0.9% NaCl. The solution was then transferred to the volumetric flask containing 0.5 g of acetaminophen and 0.59 g of phenacetin. The volume was adjusted to 100 mL with 0.9% NaCl to obtain a mixed solution of acetaminophen (0.5% (w / v)), phenacetin (0.59% (w / v)) and oxycodone (0.4% (w / v)).

[0085] 2. Fifty male SD rats (weighing 200-220 g) were acclimatized to the environment for one week, with free access to water and standard lighting. They were then randomly divided into groups of 10 rats each.

[0086] Group A: Normal control (sham surgery group), administered an equal volume of mixed solution (0.9% NaCl containing 20% ​​(v / v) ethanol) by gavage. Group B: Negative control, administered by gavage with an equal volume of a mixed solution (0.9% NaCl containing 20% ​​(v / v) ethanol). Group C: Positive control, administered an equal volume of oxycodone by gavage at a dose of 4 mg / kg; Group D: 0.5% (w / v) acetaminophen and 0.59% (w / v) phenacetin were administered by gavage at a dose of 50 mg / kg acetaminophen + 59 mg / kg phenacetin. Group E: A mixed aqueous solution of acetaminophen (0.5% (w / v)), phenacetin (0.59% (w / v)) and oxycodone (0.4% (w / v)) was administered by gavage at a dose of acetaminophen 50 mg / kg + phenacetin 59 mg / kg + oxycodone 4 mg / kg.

[0087] For groups B, C, D, and E, a rat model of neuropathic pain was established using partial sciatic nerve ligation (PSNL). Specifically, after an intraperitoneal injection of sodium pentobarbital (50 mg / kg), the rats were placed prone on an operating table, their right hind leg was shaved, and disinfected with povidone-iodine. The skin was incised, the subcutaneous tissue was separated, and the sciatic nerve was exposed. The main trunk of the sciatic nerve was freed, and four circular ligations were made every 1 mm using 3-0 chromium catgut, with consistent tension. Slight twitching of the limb was observed at this point. The subcutaneous tissue and skin were then sutured.

[0088] For Group A, after exposing the right sciatic nerve trunk, only four ligatures were placed around the nerve trunk, without ligation.

[0089] On the second day after surgery, rats in each group were administered the corresponding drug via gavage once daily for 5 consecutive days. Sixty minutes after the fifth gavage administration, a mechanical pain sensitivity test was performed: rats were placed in a specialized experimental chamber and allowed to acclimatize for 15 minutes. The skin on the right paw of the rat was stimulated using an electronic pain meter, with the intensity of stimulation gradually increased. The intensity of stimulation at which paw withdrawal occurred was recorded. Each rat was tested 5 times, with 5-minute intervals between each test, and the average value was taken as the mechanical pain withdrawal reflex threshold. A thermal pain sensitivity test was performed: rats were placed on a hot plate of a hot plate apparatus at a temperature of 55±0.5℃. The reaction time of the rat's paw withdrawing from the thermal stimulus was measured. Each rat was tested 3 times, with 10-minute intervals between each test, and the average value was taken as the latency period of the thermal paw withdrawal response.

[0090] III. Results Table 6 Comparison of mechanical withdrawal response thresholds in rats of different groups ( ±SE)

[0091] Compared to Group B, * P Less than 0.05 ** P Less than 0.01; compared with group C, ## P Less than 0.01.

[0092] Table 7 Comparison of latency of heat-induced paw retraction response in rats of different groups ( ±SE)

[0093] Compared to Group B, * P Less than 0.05 ** P Less than 0.01; compared with group C, # P Less than 0.05.

[0094] The experimental results on enhancing the analgesic effect of the centrally acting analgesic oxycodone are shown in Tables 6 and 7. The results indicate that in a rat model of neuropathic pain, although oxycodone has a significant analgesic effect, its intensity is increased by more than 20% when combined with the low-dose combination of acetaminophen and phenacetin of this invention. Statistical analysis showed that the difference was statistically significant or highly significant. This result demonstrates that the combination of oxycodone and the acetaminophen and phenacetin of this invention, when used in a compound preparation, can significantly enhance the analgesic effect of the centrally acting analgesic, and this compound preparation has clinical application value.

[0095] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A composition of acetaminophen and phenacetin, characterized in that, Including acetaminophen and phenacetin; said phenacetin can inhibit liver damage caused by acetaminophen.

2. The composition of acetaminophen and phenacetin according to claim 1, characterized in that, The weight ratio of acetaminophen to phenacetin is 1:(0.1~2.5).

3. The composition of acetaminophen and phenacetin according to claim 1 or 2, characterized in that, The composition is in the form of an oral or injectable formulation.

4. The use of the composition of acetaminophen and phenacetin according to any one of claims 1 to 3 in the preparation of antipyretic and analgesic drugs.

5. The use of the composition of acetaminophen and phenacetin according to any one of claims 1 to 3 in the preparation of a nonspecific anti-inflammatory drug.

6. The use of the composition of acetaminophen and phenacetin according to any one of claims 1 to 3 in the preparation of a centrally acting analgesic.

7. An anti-inflammatory composition, characterized in that, It includes triterpenoid saponins and the composition of acetaminophen and phenacetin as described in any one of claims 1 to 3.

8. The anti-inflammatory composition according to claim 7, characterized in that, The triterpenoid saponin compound is glycyrrhizin.

9. An analgesic composition, characterized in that, Includes opioid analgesics and the combination of acetaminophen and phenacetin as described in any one of claims 1 to 3.

10. The analgesic composition according to claim 9, characterized in that, The opioid analgesic mentioned is oxycodone.

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