Amoxicillin Drug - Medicinal Chemistry & Uses

By: Pharma Tips | Views: 12109 | Date: 20-Oct-2011

Amoxicillin belongs to a class of antibiotics called the Penicillins. The chemical structure of the Penicillin antibiotics contain a highly reactive β-lactam ring. This ring can be opened in neutral or basic solutions which can result in an inactive drug. The ring is also acted on by β-lactamase, which is an enzyme produced by some bacteria that can degrade Penicillin antibiotics.

Introduction to Amoxicillin

    Amoxicillin belongs to a class of antibiotics called the Penicillins.  The chemical structure of the Penicillin antibiotics contain a highly reactive β-lactam ring.  This ring can be opened in neutral or basic solutions which can result in an inactive drug.  The ring is also acted on by β-lactamase, which is an enzyme produced by some bacteria that can degrade Penicillin antibiotics.  Therefore, Penicillin antibiotics need to have chemical structures added to increase their acid stability and their β-lactamase resistance.  Adding an electron withdrawing group onto the 6-position amide group (located on the β-lactam ring) can increase its acid stability by making the amide oxygen less nucleophillic.  This ensures that the amide oxygen will not attack the β-lactam ring's carbonyl group to open it.

    Adding a bulky substituent (like a benzene ring) to this same position, covers the β-lactam ring’s carbonyl group and can increase the drugs β-lactamase resistance.  To increase the spectrum of the penicillin, a polar group can be added to the 6-position amide group.  This allows the drug to be active against gram negative bacteria as well as gram positive.  The polar groups allow the drug to cross the gram negative cell wall through porins.  Amoxicillin has an electron withdrawing group with a polar hydroxyl group added to the 6-position amide.  This increases its spectrum of action and acid stability when comparing it to other Penicillins, like Ampicillin.  However, Amoxicillin's substituent does not cover the β-lactam ring.  This makes it susceptible to β-lactamase and it can be degraded by resistant bacteria.

Amoxicillin Drug

Mechanism of Action

    The Penicillins were one of the first antibiotics discovered and they act on bacteria by preventing the cross linking of peptidoglycan in the bacterial cell wall.  Peptidoglycan is the “backbone” of the bacterial cell that gives the cell its rigidity.  Without the peptidoglycan the cell wall cannot handle the pressure and will rupture and the cell will die.  The Penicillin antibiotics resemble the transition state of the cross linking reaction and the Ala-Ala terminal of the peptidoglycan therefore, they are acted on by the transpeptidase enzyme.

Resistance

    As mentioned before, resistance tends to occur if the bacteria produce and enzyme called β-lactamase.  This enzyme is located between the bacteria’s outer membrane and peptidoglycan in gram negative bacteria.  The enzyme attacks the carbonyl group of the β-lactam ring and degrades the drug.  This can be avoided if a bulky substituent is added to the 6-position to cover the reactive ring.  However, Amoxicillin does not have a bulky group attached, therefore, it can be used in combination with a β-lactamase inhibitor.  Amoxicillin is normally added to Clavulanic Acid, a β-lactamase inhibitor that is acted on by the β-lactamase and is used up allowing the Amoxicillin to kill the bacteria without getting degraded.  Resistance still occurs with Amoxicillin which has limited its use.  There are other medications with less resistance and a broader spectrum available for use.

Clinical Uses of Amoxicillin

    The most common trade names of Amoxicillin are Amoxil, Amoxicot, DisperMox, Moxilin, and Trimox.  It is also used with Clavulanic Acid in Augmentin.  Clavulanic acid is a β-lactamase inhibitor which gets used up and Amoxicillin is not degraded by the bacteria’s β-lactamse.  Amoxicillin can be used for many different indications.  Some of them include:  urinary tract infection, respiratory tract infection, and infections of the skin.  Also, bacterial infections caused by E. coli, streptococci, H. influenzae, and N. gonorrhoeae (Amoxicillin is not the drug of choice for a gonorrhea infection).(7)

Doses and Dosage Forms

    Amoxicillin is available in many dosage forms including: 250 and 500 mg capsules,oral powder for suspension in concentrations 125 mg/5ml, 200mg/5ml, 250mg/5ml, 50mg/ml, and 400mg/5ml; 500 and 875 mg tablets; 125, 200, 250, 400 mg oral chewable tablets; and 200, 400, 600 mg tablets for suspension.  Amoxicllin can be taken with or without food.  The suspension needs to be shaken before the dose is given.  The dose given depends on the type of infection, but  it is normally given every 8 to 12 hours a day.(7)

Adverse Effects

    Amoxicillin should not be taken if the patient is allergic to Penicillin.  They should also be careful if they are sensitive to Cephalosporins.  The most common adverse effects are rash, diarrhea, nausea, and vomiting.  The most serious side effect is an allergic reaction (itching, redness, or inflammation).  If an allergic reaction occurs, Adrenaline should be given.(7)

Drug Interactions

    Some drug interactions that should be known are Methotrexate, Warfarin, Ethinyl Estradiol, and Norgestrel.  The most serious drug interactions are with Methotrexate and Warfarin.  Amoxicillin causes the Methotrexate levels to increase and can cause toxicity.  When Amoxicillin is used with Warfarin there is a greater risk of bleeding.  The patient should have the INR and prothrombin times monitored.  It is important to talk to a doctor before starting Amoxicillin therapy.  The patient should tell the doctor any other medications, herbal therapies, or non-prescription medications that they are taking before taking Amoxicillin.(7)

Other Information

Amoxicillin is a pregnancy category B which means that either animal testing has shown no side effects to the fetus or that there have been some animal studies that have shown some fetal risk, but there have not been any controlled studies in humans.(7)

Future of Amoxicillin

    In the future Amoxicillin will probably not be used very often due to bacterial resistance.  This drug has been used for many years and sometimes used when it is not needed.  This increases the risk of resistance and Amoxicillin is already sensitive to β-lactamase.  There are many new antibiotics that are more resistant to β-lactamase and have broader spectrums against bacteria, therefore the use of Amoxicillin will decrease in the future.
Previous Page Next Page

People Searching On This Page:
  • from medicinal chemistry use of amoxicillin
  • chemistry of amoxicillin
  • medicinal chemistry of amoxa
  • amoxacillin sensevity medicinal chemistry
  • introduction of amoxicillin
  • amoxicillin medicinal chemistry
  • amox med chem
  • .drug chemistry:amoxicillin
  • amoxicillin is produced by attaching a hydroxyl group
  • medicinal chemistry of amoxicillin
  • info porteirinha.mg.gov.br loc:IN
  • info hemominas.mg.gov.br loc:IN
  • info valadares.mg.gov.br loc:IN
  • info amide.com.br loc:IN
  • info fhemig.mg.gov.br loc:IN

Related Pages


B.Pharm/M.Pharm for Drugs Inspector under Directorate of Drugs control

B.Pharm/M.Pharm for Drugs Inspector under Directorate of Drugs control

Jobs | Drug Inspector
Date:
02-Mar-2016  Views: 27545

Online applications are invited from Indian Citizen and such other national as declared eligible by Government of India for recruitment to the 88 post ...
Drug Inspector Jobs Under Food & Drug Administration

Drug Inspector Jobs Under Food & Drug Administration

Jobs | Drug Inspector
Date:
22-Apr-2015  Views: 18108

MPSC invites applications by online method for post of Drug Inspector under Food & Drug Administration, Medical Education and Research Services. For t ...
Career as Drug Inspector at Food & Drug Administration

Career as Drug Inspector at Food & Drug Administration

Jobs | Drug Inspector
Date:
16-Feb-2015  Views: 12578

Online applications are invited from candidates by Food & Drug Administration department Chhattisgarh for given vacancies. ...
Drugs Inspector Job Vacancy  in Drugs Control Department of KPSC

Drugs Inspector Job Vacancy in Drugs Control Department of KPSC

Jobs | Drug Inspector
Date:
05-Jul-2012  Views: 35176

Vacancy for Drugs Inspector in Drugs Control department of KPSC - Freshers may apply ...
Drug Inspector in A.P. Drugs Control Job Vacancy

Drug Inspector in A.P. Drugs Control Job Vacancy

Jobs | Drug Inspector
Date:
18-Feb-2012  Views: 23044

Recruitment applications are invited On-line through the proforma Application to be made available on WEBSITE (apspsc.gov.in) in from 22/02/2012 to 22 ...
Post Your Comments (No Login Require)
Name : (required)
Email : (required)
Website :

Comment : (required)

24  + 3 =     
Comments
People Searched About:
From Medicinal Chemistry Use Of Amoxicillin   |   Chemistry Of Amoxicillin   |   Medicinal Chemistry Of Amoxa   |   Amoxacillin Sensevity Medicinal Chemistry   |   Introduction Of Amoxicillin   |   Amoxicillin Medicinal Chemistry   |   Amox Med Chem   |   Info Porteirinha.Mg.Gov.Br Loc:IN   |   Info Hemominas.Mg.Gov.Br Loc:IN   |   Info Valadares.Mg.Gov.Br Loc:IN   |   Info Amide.Com.Br Loc:IN   |   Info Fhemig.Mg.Gov.Br Loc:IN   |   Augmentin Parentral Dosage   |   Info Jucemg.Mg.Gov.Br Loc:IN   |   Amide.Com.Br Loc:IN   |   Penicillin Pharma Chemistry   |   Amoxicillin 5Ml/500   |   Electron Withdrawing Group Ampicillin   |  
Google : 947 times | Yahoo : 16 times | Bing : 334 times |