Invanz Sandbox: Difference between revisions

Invanz (Ertapenem) is a 1-beta-methyl carbapenem antibiotic that is designed to treat multi drug resistant bacterial infections such as intra-abdominal infections, skin and skin suture infections, community-acquired pneumonia, complicated urinary tract infections including pyelonephritis, acute pelvic infections, and can be used as a prophylactic measure prior to colorectal surgery. Invanz is an injectable antibiotic that can be administered intramuscularly, and is generally known to be an antibiotic to treat mostly life-threatening infections and is used sparingly <ref>Merck, Sharp, and Dohme Corporation. Highlight of Prescribing Information: Invanz. http://www.merck.com/product/usa/pi_circulars/i/invanz/invanz_pi.pdf (accessed November, 12 2016)</ref><ref name="merck">...</ref>.  

Invanz is used to treat a range of bacterial infections caused by Gram positive and Gram negative bacteria as well as a range of both aerobic and anaerobic bacteria. Invanz works by inhibiting cell wall synthesis via binding to penicillin binding proteins (PBPs). Invanz is stable against hydrolysis from many beta-lactamases including penicillinases and cephalosporinases, but is unstable against metallo-beta-lactamases <ref name="merck" />. Beta-lactamases are secreted by bacteria to provide resistance to antibiotics; however, Invanz is relatively unaffected by these beta-lactamases and thus is an effective treatment for various bacterial infections <ref>PMID: 25561890</ref>. The unique structural features of Invanz equip this drug with some of the widest spectrum and most potent antimicrobial activity of carbapenem antibiotics today <ref>PMID: 12951340</ref>.  

<scene name='74/746003/Invanz_ball_and_stick/1'>Invanz</scene> is a carbapenem which is a beta-lactam antibiotic (contains a beta lactam ring) that has antimicrobial action via inhibition of cell wall synthesis. This class of antibiotics is known for its broad spectrum of activity, and its structure allows it to bind penicillin binding proteins (PBPs) to inhibit bacterial cell wall synthesis in a variety of bacterial types <ref>PMID: 17488146</ref><ref name="Invanz1">...</ref>. Antibiotic resistance to carbapenems largely results from ability of the bacterial species to secrete beta-lactamase enzymes that prevent the antimicrobial from accomplishing its job. Beta-lactamases work by attacking and cleaving the beta-lactam ring of antibiotics before the antibiotic reaches its target such as the penicilling binding proteins <ref>PMID: 25485972</ref>. Invanz has resistance to many beta-lactamases since it has a trans-1-hydroxyethyl group that confers resistance of the antibiotic to degradation by most beta-lactamases <ref>PMID: 15150178 </ref> <ref name="hammond">...</ref>. The beta lactam ring is a four-membered, nitrogen-containing ring that binds to PBPs, thus making them unable to continue bacterial cell wall synthesis. PBPs are enzymes found in the cell membrane that aid in cross-linking of peptidoglycan during cell wall synthesis <ref>PMID: 18266856</ref>. By inactivating PBPs and inhibiting cell wall synthesis, bacterial cell death will occur since the bacterial cells will lyse due to osmotic pressure <ref>Page, M.L. The mechanisms of reactions of beta lactam antibiotics. Accounts of Chemical Research, 1984, 17(4), 144-151 DOI: 10.1021/ar00100a005</ref>. There are various crystal structures of Invanz that help to elucidate its mechanism of action and effectiveness against some species of bacteria that are able to resist inhibition by other classes of antibiotics. The <scene name='74/746003/4qu3/1'>GES-2 Ertapenem Acyl-Enzyme Complex</scene> is a crystallized structure of Invanz bound to the GES-2 beta-lactamase in ''Pseudomonas aeruginosa''. GES-1, GES-2, and GES-3 are the Guina Extended Spectrum beta-lactamases that help some bacteria resist attack of antibiotics <ref>PMID: 15225858</ref>. This crystal structure complex is important for illustrating the acylation event between the GES-2 enzyme and the Ertapenem. Acylation of the enzyme leads to inactivation of the GES-2 beta-lactamase, thus making the Ertapenem and effective treatment against the bacteria <ref>PMID: 18922024</ref> The <scene name='74/746003/3zgp/1'>NMR structure of the catalytic domain from Enterococcus faecium l,d-transpeptidase acylated by ertapenem</scene> shows that Invanz is an effective treatment against bacteria such as ''E. faecium'' and ''Mycobacterium tuberculosis''. PBPs vital for peptidoglycan synthesis are replaced by l,d-transpeptidases (ltds) in an ampicillin-resistant strain of ''E. faecium'' and in ''M. tuberculosis''. This structure shows that bacterial strains such as ''E. faecium'' and ''M. tuberculosis'' are successfully inhibited by ertepenem through acylation of the ltd <ref>PMID: 23574509</ref> The <scene name='74/746003/3m6b/1'>crystal structure of the pre-isomerized ertapenem covalent adduct with the M. tuberculosis beta-lactamase </scene>  and the <scene name='74/746003/3m6h/1'>crystal structure of the post-isomerized ertapenem covalent adduct with the M. tuberculosis beta-lactamase </scene> are structures from a publication that determined carbapenems such as Invanz can inhibit a bacterium such as ''M. tuberculosis'' by acetylating and slowly de-acetylating the acyl-enzyme complex in order to inhibit the beta-lactamase and effectively inhibit bacterial cell wall synthesis <ref>PMID: 23574509</ref>.  

There are various structural features of Invanz that make make administration of the drug easy. Older carbapenems required patients to take a dehydropeptidase-1 (DHP-1) inhibitor since the DHAP enzyme found in the human renal system could interfere with the action of the carbapenem by degrading the antibiotic  <ref name="Invanz1" />. Invanz is a unique antibiotic because it has a 1-beta-methyl substituent that shields the beta-lactam carbonyl from DHP-1 degradation <ref name="hammond">...</ref>. The meta-substituted benzoic acid substituent increases the molecular weight and makes the drug more soluble in nonpolar solvents. Additionally, the carboxylic acid substituent becomes ionized at physiological pH, so the ertapenem has a net negative charge. Increased solubility in non polar solvents and the net negative charge allows the drug to bind human plasma proteins with an extended half-life in the blood stream, and thus the drug only has to be administered once daily <ref name="hammond" />. Invanz largely travels in the bloodstream bound to the human plasma protein albumin <ref name="merck" />.