Methicillin sodium salt (also known as Meticillin sodium) is a β-lactam antibiotic of the penicillin class. It acts by inhibiting penicillin-binding proteins that are involved in the synthesis of peptidoglycan. Compared to other penicillins that face antimicrobial resistance due to β-lactamase, it is less active, can be administered only parenterally, and has a higher frequency of interstitial nephritis, an otherwise-rare adverse effect of penicillins. However, selection of methicillin depended on the outcome of susceptibility testing of the sampled infection, and since it is no longer produced, it is also not routinely tested for any more. It also served a purpose in the laboratory to determine the antibiotic sensitivity of Staphylococcus aureus to other penicillins facing β-lactam resistance; this role has now been passed on to other penicillins, namely cloxacillin, as well as genetic testing for the presence of mecA gene by PCR.
Physicochemical Properties
| Molecular Formula | C17H19N2O6S-.NA+ |
| Molecular Weight | 402.39736 |
| Exact Mass | 402.086 |
| CAS # | 132-92-3 |
| Related CAS # | Methicillin;61-32-5;Methicillin sodium hydrate;7246-14-2 |
| PubChem CID | 23667627 |
| Appearance | White to off-white solid powder |
| Boiling Point | 640ºC at 760 mmHg |
| Melting Point | 196-197℃ |
| Flash Point | 340.9ºC |
| Vapour Pressure | 2.94E-17mmHg at 25°C |
| Hydrogen Bond Donor Count | 1 |
| Hydrogen Bond Acceptor Count | 7 |
| Rotatable Bond Count | 5 |
| Heavy Atom Count | 27 |
| Complexity | 606 |
| Defined Atom Stereocenter Count | 3 |
| SMILES | CC1([C@@H](N2[C@H](S1)[C@@H](C2=O)NC(=O)C3=C(C=CC=C3OC)OC)C(=O)[O-])C.[Na+] |
| InChi Key | MGFZNWDWOKASQZ-UMLIZJHQSA-M |
| InChi Code | InChI=1S/C17H20N2O6S.Na/c1-17(2)12(16(22)23)19-14(21)11(15(19)26-17)18-13(20)10-8(24-3)6-5-7-9(10)25-4;/h5-7,11-12,15H,1-4H3,(H,18,20)(H,22,23);/q;+1/p-1/t11-,12+,15-;/m1./s1 |
| Chemical Name | sodium;(2S,5R,6R)-6-[(2,6-dimethoxybenzoyl)amino]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate |
| Synonyms | Methicillin sodium salt |
| HS Tariff Code | 2934.99.9001 |
| Storage |
Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment, avoid exposure to moisture. |
| Shipping Condition | Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs) |
Biological Activity
| Targets | β-lactam |
| ln Vitro | Methicillin sodium salt (100 μg/mL; 18 h) incubates intracellularly for 18 hours before killing S. aureus[1]. |
| ln Vivo |
Methicillin sodium salt (42.5 and 85 mg/kg) against enterococcus in leukocytes, administered intramuscularly four times a day for 21 days or until the cells die naturally[1]. Mice infected with methicillin sodium salt (400 mg/kg; intraperitoneally once) fare better than the comparison group[2]. Mice with infection cannot die if methicillin sodium salt (400 mg/kg; i.h. once) is administered[2]. |
| Cell Assay |
Cell Line: Leukocytes Concentration: 100 μg/mL Incubation Time: 18 hours Result: demonstrated superior results in an aerobic environment and successfully eradicated S. aureus at a 3.13 μg/mL bactericidal concentration. |
| Animal Protocol |
Animal Model: White New Zealand rabbits, weighing 2.0 to 3.0 kg[1] Dosage: 42.5 and 85 mg/kg Administration: Intramuscular injection; 42.5 and 85 mg/kg four times daily; for 21 days or till spontaneous death Result: Inhibited enterococcus at 24 hours with a half-live of 1.1 h, but showed no statistical significance to rabbits. |
| References |
[1]. Antimicrob Agents Chemother. 1977 Oct;12(4):484-9. [2]. J Infect Dis. 1972 May;125(5):486-90. [3]. Int J Nanomedicine. 2018 Nov 29;13:8095-8104. |
| Additional Infomation |
Methicillin sodium is an organic sodium salt. It contains a methicillin(1-). Methicillin Sodium is the sodium salt form of methicillin, a semisynthetic beta-lactam penicillin antibiotic with beta-lactamase resistant activity. Methicillin sodium is bactericidal and binds to specific penicillin-binding proteins on the bacterium and inhibits the transpeptidation enzyme, thereby preventing the cross-linking of peptidoglycans. This leads to an interruption of the bacterial cell wall and causes bacterial lysis. Methicillin sodium is active against beta-lactamase producing staphylococci. One of the PENICILLINS which is resistant to PENICILLINASE but susceptible to a penicillin-binding protein. It is inactivated by gastric acid so administered by injection. |
Solubility Data
| Solubility (In Vitro) |
DMSO : ~125 mg/mL (~310.64 mM ) H2O : ~100 mg/mL (~248.51 mM ) |
| Solubility (In Vivo) |
Solubility in Formulation 1: ≥ 2.08 mg/mL (5.17 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.08 mg/mL (5.17 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Solubility in Formulation 3: ≥ 2.08 mg/mL (5.17 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly. Solubility in Formulation 4: 10% DMSO+40% PEG300+5% Tween-80+45% Saline: ≥ 2.08 mg/mL (5.17 mM) Solubility in Formulation 5: 100 mg/mL (248.51 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication. (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 2.4851 mL | 12.4254 mL | 24.8509 mL | |
| 5 mM | 0.4970 mL | 2.4851 mL | 4.9702 mL | |
| 10 mM | 0.2485 mL | 1.2425 mL | 2.4851 mL |