Synthesis, Characterization, Antimicrobial and Anti-Inflammatory Investigations of Acetaminophen Complexes of Cu(Ii), Mg(Ii) and Zn(Ii) Ions
Chapter One
Aim
This research aimed to synthesize, characterize, and investigate the antimicrobial and anti-inflammatory properties of Mg(II), Zn(II), and Cu(II)as the central atoms using acetaminophen as the complexing agent or ligand.
Objectives
The objectives of the study were to:
- prepare of the solid complexes of Mg(II), Zn(II), and Cu(II)ions of acetaminophen;
- characterize the metal-acetaminophen complexes using UV-Vis spectrometer, Infrared Spectroscopy, magnetic susceptibility and molar conductance;
- estimate the crystallite size of the complexes using X-Ray diffractometer;
- determine the antimicrobial activity of the solid complexes of Mg(II), Zn(II), and Cu(II) ions of acetaminophen on bacteria and fungi;
- investigate the acute toxicity of the solid complexes of Mg(II), Zn(II), and Cu(II) ions of acetaminophen;
- investigate the anti-Inflammatory property of the solid complexes of Mg(II), Zn(II), and Cu(II) ions of
CHAPTER TWO
LITERATURE REVIEW
Medications that Contain Acetaminophen as their Active Ingredient
Acetaminophen is the most common drug ingredient in America. There are more than 600 medicines that contain acetaminophen as an active ingredient, including prescription (Rx) and over-the-counter (OTC) medicines such as Tylenol. Acetaminophen is an external analgesic that works as a pain reliever (for mild to moderate pain) and fever reducer (U.S. FDA, 2014).
Acetaminophen is a generic name para-acetyl aminophenol and there are more than six thousand medicines that contain acetaminophen. Medicines that contain acetaminophen are over-the- counter (OTC) brands such as Excedrin, Paracetamol, Midol, Mucinex, Sinus Max, Nyquil, Robitussin, Sudafed, Triaminic, Tylenol and prescription medicines like Endocet, Percocet and Vicodin. Sometimes, acetaminophen is the only active drug ingredient in a medicine. This is a single-ingredient medicine like regular strength Tylenol and extra strength Tylenol. Acetaminophen can also be found in many products with more than one active ingredient (combination medicines), such as Vicks Nyquil Severe Cold or Percocet (Hamilton, 2013; Raymond et al., 2017).
Chemical Properties of Acetaminophen
Acetaminophen (Figure 1.1) consists of a benzene ring core, substituted by one hydroxyl group and the nitrogen atom of an amide group in the Para (1,4) pattern (Bertolini et al., 2006). The amide group is acetamide (ethanamide). It is an extensively conjugated system, as the lone pair of electrons on the hydroxyl oxygen, the benzene pi cloud, the nitrogen lone pair of electrons, the p-orbital on the carbonyl carbon, and the lone pair of electrons on the carbonyl oxygen is all conjugated. The presences of two activating groups also make the benzene ring highly reactive toward electrophilic aromatic substitution. The conjugation greatly reduce the basicity of the oxygen and the nitrogen, while making the hydroxyl group acidic through delocalization of charge developed on the phenoxide anion.
Acetaminophen
Paracetamol (Figure 2.1) is part of the class of drugs known as “aniline analgesics”. It is the only such drug still in use today (Bertolini et al., 2006). It is not considered a Nonsteroidal Anti-Inflammatory Drug (NSAID) because it does not exhibit significant anti-inflammatory activity (Viswanathan et al., 2008). This is despite the evidence that paracetamol and NSAIDs have some similar pharmacological activity (Byrant et al., 2007).
Maximum Daily Limit of Acetaminophen
The amount of acetaminophen in an individual product is included on the medicine label and is measured in milligrams (mg). For some populations, such as people with underlying liver disease or those who drink three or more alcoholic beverages every day, the daily limit, may be less (US FDA, 2014). Most OTC medicines for adults that contain acetaminophen have one of the following three strengths:
- 325 mg per tablet/capsule or liquid dose: “regular strength”
- 500 mg per tablet/capsule or liquid dose: “extra strength”
- 650 mg per tablet/capsule: “extended relief”
For acetaminophen-containing prescription combination medicines such as Percocet and Vicodin, the amount of acetaminophen is now limited to 325 mg per tablet/capsule. Following a request made by the U.S.
Food and Drug Administration (FDA) to manufacturers to lower the dose of acetaminophen in these medicines. Prior to this change, many prescription opioid medicines contained unit doses of acetaminophen of 500 mg or higher. Limiting the amount of acetaminophen per dosage unit of these prescription combination medicines is expected to help reduce the risk of severe liver injury from inadvertent acetaminophen overdose (US FDA, 2014). With different strengths of acetaminophen across many different types of medicine, it is critical to read and follow medicine labels to understand dosage strength and unique dosing directions for each product and to avoid taking multiple acetaminophen-containing medicines at the same time.
Health Effects of Acetaminophen
Taking more acetaminophen than directed and exceeding the maximum daily dose of 4,000 mg is considered an overdose and can lead to severe liver damage (U.S. FDA, 2012). Like many drugs, acetaminophen is metabolized in the liver, which is an essential organ that filters the blood coming from the digestive tract before passing it to the rest of the body. Most acetaminophen is broken down in the liver and converted into harmless substances that are excreted in the urine.
The percent of overall acetaminophen users who exceed the maximum labeled dose when using the medicine is very low, and in the vast majority of instances it does not result in side effects or adverse events such as liver damage. However, acetaminophen overdose is the leading cause of acute liver failure (ALF), and is responsible for nearly half of all ALF cases (Larson et al., 2005). Acute liver failure is rare in the United States, with an estimated 2,000 cases per year. According to the U.S. Liver Failure Study Group (a consortium of investigators and clinical centers that consolidate data), acetaminophen-related ALF results in roughly 450 deaths each year (Fontana and Adams, 2006). It is important to note that the number of deaths is primarily due to intentional overdose of acetaminophen (suicide or attempted self-harm), while accidental or unintentional overdose is linked to an estimated 100-150 deaths each year (Fontana and Adams, 2006).
CHAPTER THREE
MATERIALS AND METHODS
Materials
All chemicals were of analytical grade. Acetaminophen (product of Sigma Aldrich) was obtained from Bristol Scientific Company, Lagos, Nigeria. Zinc Chloride Hexahydrate (ZnCl2.6H2O), Magnesium Chloride Hexahydrate (MgCl2.6H2O) and Copper (II) Chloride dihydrate (CuCl2.2H2O) were obtained from the Department of Chemistry, Ahmadu Bello University, Zaria. The albino rats were housed in standard animal cages in the animal house section of the Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Ahmadu Bello University, Zaria.
Preparation of Solid Complexes
The metal complexes ( Cu(II), Mg(II) and Zn(II)) were prepared according to the method used by Oluwatoosin et al. (2014). Copper (II) complex was prepared by the addition of(0.51 g, 3 mmol) of CuCl2.2H2O in 20mL of distilled water to (0.91 g, 6 mmol) of acetaminophen in 60 mL of distilled water, the mixture was stirred using magnetic stirrer at room temperature until the dissolution of acetaminophen occurred, the mixture was heated in water bath for 6 hours. The solution was allowed to cool down overnight during which brown crystals were obtained. The crystals were filtered off, washed with distilled water and dried in a desiccator for about 48 hours.
CHAPTER FOUR
RESULTS
Physical Measurement
The reactions of Acetaminophen with magnesium chloride and zinc chloride gave white solid complexes while the reaction of Acetaminophen (AC) with copper (II) chloride gave a brown solid complex. The purity of the three complexes was checked by taking the melting points. The solubility of the complexes was carried out by dissolving the complexes in ethanol, water, methanol and Dimethyl sulfoxide (Table 4.1).
The decomposition temperature, molecular formula, percentage yield and molar conductance of acetaminophen (ligand), Zn(II), Mg(II) and Cu(II) complexes prepared are presented in Table 4.2. The complexes were obtained in good yield, the molar conductance value of zinc, magnesium and copper complexes were 0.02, 0.03 and 0.05 (mS/cm) respectively.
The electronic absorption spectral data and magnetic susceptibility of acetaminophen, magnesium, zinc and copper complexes are presented in Table 4.3. The shift in lambda max is and evidence of complexation. The observed magnetic moment in the table falls within the range observed for octahedral geometry (Koushik et al 2007).
The Fourier-transform infrared spectroscopy (FTIR) data 0f acetaminophen, magnesium, zinc, magnesium and copper complexes are presented in Table 4.4. The Infrared spectrum of acetaminophen showed bands at 3321, 3160, 3108 and 1551 cm-1. Magnesium complex showed bands at 3324 and 1547 cm-1, zinc complex showed bands at 3205, 3321 and 1551 cm-1, while copper complex showed bands at 3317 and 1561.
CHAPTER FIVE
DISCUSSION
The reactions of Acetaminophen with the metal (II) chlorides (Zn, and Mg) gave white solid complexes while that of acetaminophen with copper (II) chloride gave a brown solid complex (Table 4.2), according to equations 5.1- 5.1
ZnCl2.6H2O + 2(C8H9NO2) → [Zn(C8H9NO2)2(H2O) Cl] Cl. H2O + 4H2O…….eq
All the complexes were obtained in good yield (Table 4.2). The purity of the complexes was checked by taking the melting points. The sharp melting point of the complexes is an indication of the purity of the complexes (Refat et al., 2013). The solubility of acetaminophen and the metal complexes was determined by dissolving the complexes in ethanol, water, methanol and dimethyl sulfoxide. All the complexes were soluble in ethanol, methanol and dimethyl sulfoxide but were found to be sparingly soluble in water (Table 4.1).The molar conductivity of the complexes was determined in methanol. The molar conductance values (Table 4.2) were in the range of 0.02mS/cm to 0.05 mS/cm. The low molar conductivity of the complexes is an indication of the non-electrolytic or covalent nature of the metal complexes (Refat et al., 2013). Analytical data of the compounds, together with their physical properties are consistent with proposed molecular formula.
CHAPTER SIX
CONCLUSION ANDRECOMMENDATION
Conclusion
Cu(II)-AC, Mg(II)-AC and Zn(II)-AC have been synthesized and characterized by FTIR spectroscopy, electronic spectroscopy, conductivity measurement and XRD. It was proven that the formation of complexes occurred via both C=O and –OH groups from Acetaminophen.
The antibacterial studies showed that all the metal complexes had better antibacterial activity than acetaminophen and their metal chlorides. Based on the observations made, the three complexes were considered to be moderately toxic and slightly toxic according to Hodge and sterner (2005).
There was also a general decrease in the diameter of the edema. Increase in the percentage Anti inflammatory effect was observed at the fourth and fifth hours for the three complexes, and was at its peak was in the third hour. The percentage anti-inflammatory effect of piroxicam at the 3rd hour was 46.5%. Since the percentage anti-inflammatory effects of the complexes are higher than that of the normal saline, we can conclude that the complexes have anti-inflammatory activity.
Recommendations
Based on the findings of this study, the following recommendations are hereby made:
- Analgesic activity of Cu(II)-AC, Mg(II)-AC and Zn(II)-AC complexes should be determined to compare the analgesic activity of Acetaminophen and the synthesized complexes.
- Median effective dose (ED50) of Cu(II)-AC, Mg(II)-AC and Zn(II)-AC should be carried out to determine the dose that will producea therapeutic
- There is need for further research on In-vivo antimicrobial activity of the synthesized complexes.
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