DNA gyrase; topoisomerase IV; Quinolone antibiotic

Nalidixic acid has the ability to combat a wide range of microorganisms, including Shigella spp., Brucella spp., Escherichia coli, Pasteurella spp., Klebsiella pneuiioniae, Aerobacter aeroyenes, Proteus spp., Salmonella spp., and Brucella spp. The MIC values of these microorganisms are as follows: 5.0-12.5 μg/ml, 0.5-2.5 μg/ml, 0.8-25.0 μg/ml, 1.25-30.0 μg/ml, 8-3.2 μg/ml, and 7.5-10.0 μg/ml, respectively[1].

Gram-negative bacteria are the target of nalidixic acid's greatest in vivo action, whilst Gram-positive species are typically more resilient. Maximum efficacy against E-caused systemic infections is noted. Coli, A. The ED50 values for Shigella fkxneri, Proteus mirabilis, and Aerobacter are, respectively, 25 mg/kg, 60 mg/kg, 50 mg/kg, and 62 mg/kg[1]. After being administered orally and parenterally to mice, the acute toxicity (LD50) of nalidixic acid is 3300 mg/kg orally, 176 mg/kg intravenously, and 500 mg/kg subcutaneously[1].

Fluoroquinolones are an important class of wide-spectrum antibacterial agents. The first quinolone described was nalidixic acid, which showed a narrow spectrum of activity. The evolution of quinolones to more potent molecules was based on changes at positions 1, 6, 7 and 8 of the chemical structure of nalidixic acid. Quinolones inhibit DNA gyrase and topoisomerase IV activities, two enzymes essential for bacteria viability. The acquisition of quinolone resistance is frequently related to (i) chromosomal mutations such as those in the genes encoding the A and B subunits of the protein targets (gyrA, gyrB, parC and parE), or mutations causing reduced drug accumulation, either by a decreased uptake or by an increased efflux, and (ii) quinolone resistance genes associated with plasmids have been also described, i.e. the qnr gene that encodes a pentapeptide, which blocks the action of quinolones on the DNA gyrase and topoisomerase IV; the aac(6')-Ib-cr gene that encodes an acetylase that modifies the amino group of the piperazin ring of the fluoroquinolones and efflux pump encoded by the qepA gene that decreases intracellular drug levels. These plasmid-mediated mechanisms of resistance confer low levels of resistance but provide a favourable background in which selection of additional chromosomally encoded quinolone resistance mechanisms can occur.[2]

Effects of nalidixic acid and its derivatives were investigated on mouse cells transformed by methylcholanthrene or an activated c-Ha-ras oncogene. Our findings were as follows. Nalidixic acid preferentially suppressed growth in soft agar of transformed Balb/3T3 mouse cells induced by methylcholanthrene. The suppressive effect of nalidixic acid on growth in soft agar was reversible. Nalidixic acid reversibly reduced saturation density of these transformed cells. Oxolinic acid and pipemidic acid, which are derivatives of nalidixic acid, were less effective than nalidixic acid in suppressing growth in soft agar. Nalidixic acid suppressed growth in soft agar of NIH/3T3 mouse cells transformed by an activated c-Ha-ras, without affecting the amount of ras p21 proteins as detected by an immunoblotting analysis using a monoclonal antibody. These results show that nalidixic acid reversibly suppressed the expression of transformed phenotypes that were already being expressed.https://pubmed.ncbi.nlm.nih.gov/2690912/

Absorption
Following oral administration, nalidixic acid is rapidly absorbed from the gastrointestinal tract. Bioavailability is approximately 96%. Absorption may be delayed if taken with antacids.

Route of Elimination
Following oral administration, NegGram is rapidly absorbed from the gastrointestinal tract, partially metabolized in the liver, and rapidly excreted through the kidneys. Approximately four percent of NegGram is excreted in the feces.

ABSORPTION & ELIMINATION RATES OF NALIDIXIC ACID WERE SHOWN TO BE LOW IN NEWBORN CHILDREN COMPARED WITH ADULTS, & ADULT VALUES WERE NOT OBTAINED UNTIL ABOUT THIRD YR OF LIFE. RELATIVE DISTRIBUTION VOL, HOWEVER, WERE SIMILAR IN BOTH AGE GROUPS.

IN RATS & MICE ORAL DOSES ARE RAPIDLY ABSORBED WITH PEAK BLOOD CONCN ABOUT 1 HR LATER. ...ELIMINATION IS VIA KIDNEYS, PEAKING @ ABOUT 6TH HR. 80% OF ADMIN DOSE IS ELIMINATED IN 1ST 8 HR. IN DOGS HIGHLY EFFECTIVE CONCN APPEAR IN URINE WITHIN 2-3 HR AFTER ORAL ADMIN.

ABSORPTION EFFICIENCY & RATE OF ELIMINATION OF...NALIDIXIC ACID...DECR IN PT WITH SHIGELLOSIS. POOR ABSORPTION WAS GENERALLY OBSERVED IN YOUNGER PT WITH MARKED DIARRHEA BUT THERE WAS NO READY EXPLANATION FOR DELAYED EXCRETION.

Rapidly and almost completely absorbed from the gastrointestinal tract; bioavailability is approximately 96%. Absorption may be delayed if taken with antacids.

---

Metabolism / Metabolites
Hepatic. 30% of administered dose is metabolized to the active metabolite, hydroxynalidixic acid. Rapid conjugation of parent drug and active metabolite to inactive metabolites. Metabolism may vary widely among individuals. In the urine, hydroxynalidixic acid represents 80 to 85% of the antibacterial activity.

WHEN NALIDIXIC ACID...IS INGESTED BY MAN, IT IS PARTLY EXCRETED AS FREE... /ACID/ BUT MUCH BIGGER PROPORTION IS EXCRETED AS MONOGLUCURONIDE...& CONSIDERABLE FRACTION AS 7-HYDROXYMETHYL METABOLITE...TOGETHER WITH SMALLER AMT OF LATTER IN CONJUGATED FORM. 3,7-DICARBOXYLIC ACID...IS MINOR METABOLITE.

Nalidixic acid is partially metabolized in the liver to hydroxynalidixic acid and the glucuronic acid conjugates of nalidixic acid and hydroxynalidixic acid. The drug is also partially metabolized to the dicarboxylic acid derivative; there is some evidence suggesting that this metabolite is formed in the kidney.

---

Biological Half-Life
1.1 to 2.5 hours in healthy adult patients, and up to 21 hours in patients with impaired renal function.

APPROX 96% OF ORALLY ADMIN...IS ABSORBED. PLASMA CONCN OF 20-50 UG/ML MAY BE ACHIEVED, BUT ACID IS 93-97% BOUND TO PLASMA PROTEINS. IN BODY SOME... CONVERTED TO ACTIVE HYDROXYNALIDIXIC ACID, & BOTH ARE EXCRETED INTO URINE. MOST...IS CONJUGATED IN LIVER. PLASMA T/2 IS...8 HR...MAY BE...21 HR IN...RENAL FAILURE.

Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
Limited information indicates that maternal doses of nalidixic acid up to 2 grams daily produce low levels in milk and would usually not be expected to cause any adverse effects in breastfed infants with monitoring of the infant for possible effects on the gastrointestinal flora, such as diarrhea or candidiasis (thrush, diaper rash). Nalidixic acid should be avoided while breastfeeding a glucose-6-phosphate dehydrogenase (G6PD) deficient infant. Other agents are preferred, especially while nursing a newborn or preterm infant.

◉ Effects in Breastfed Infants
Decreased weight gain, pallor, jaundice occurred in a 16-day-old infant probably caused by hemolytic anemia induced by maternal use of nalidixic acid orally 1 gram four times daily and amobarbital 65 mg orally three times daily. The infant developed jaundice, hyperbilirubinemia, reticulocytosis, eosinophilia, Heinz bodies and other signs of hemolysis 7 days after its mother was started on nalidixic acid. No G-6-PD deficiency or hemoglobin Zurich could be demonstrated.

◉ Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.

---

Interactions
...AT PHYSIOLOGICAL CONCN...NALIDIXIC ACID...DISPLACED SUBSTANTIAL AMT OF WARFARIN FROM HUMAN ALBUMIN BY NON-COMPETITIVE MECHANISM.

SYSTEMIC & URINARY ALKALINIZERS REDUCE ITS EFFECTIVENESS BY INCR ITS EXCRETION RATE. SYSTEMIC EFFECTIVENESS INCR IF URINE IS ACID.

METABOLIC ACIDOSIS WAS INDUCED IN AN 18-YEAR-OLD MALE BY AN OVERDOSE OF NALIDIXIC ACID. SIMULTANEOUS INGESTION OF PROBENECID MAY HAVE ACCENTUATED EFFECT OF INGESTED NALIDIXIC ACID BY PROLONGING ITS SERUM T/2.

Coumarin- or indandione-derivative anticoagulants, especially warfarin and dicumarol, may be displaced from protein-binding sites by nalidixic acid, resulting in increased anticoagulant effect; dosage adjustments may be necessary during and after nalidixic acid therapy.

---

View More

Antidote and Emergency Treatment
Recommended treatment consists of the following: To decrease absorption - Performing gastric lavage if overdose is noted early. Specific treatment - Administering anticonvulsants if needed for seizures. Supportive care - Administering fluids and supportive measures such as oxygen and artificial respiration if absorption has occurred. Patients in whom intentional overdose is known or suspected should be referred for psychiatric consultation.

---

Human Toxicity Excerpts
Acute toxicity from nalidixic acid may be manifested by toxic psychoses, convulsions, increased intracranial pressure, or metabolic acidosis. Vomiting, nausea, and lethargy may also occur. Because of the rapid excretion of nalidixic acid, such reactions are usually short-lived, persisting only 2-3 hours.

Human systemic effects: convulsions, hyperglycemia, sweating, and blood changes in children.

---

Non-Human Toxicity Excerpts
Nalidixic acid causes lameness in immature dogs due to permanent damage of the cartilage of weight-bearing joints.

...prolonged use of the drug /in dogs and cats/ has caused retinal degeneration leading to blindness in some cases.

---

Non-Human Toxicity Values
LD50 MOUSE ORAL 3.3 G/KG

LD50 MOUSE SUBCUTANEOUS 0.5 G/KG

LD50 MOUSE INTRAVENOUS 0.176 G/KG

LD50 Rat oral 1160 mg/kg

---

Protein Binding
Nalidixic acid is 93% bound to protein in the blood, and the active metabolite, hydroxynalidixic acid is 63% bound.

[1]. 1,8-NAPHTHYRIDINE DERIVATIVES. A NEW CLASS OF CHEMOTHERAPEUTIC AGENTS. J Med Pharm Chem. 1962 Sep:5:1063-5.

[2]. Mechanism of Action of and Resistance to Quinolones. Microb Biotechnol.2009 Jan;2(1):40-61.

A synthetic 1,8-naphthyridine antimicrobial agent with a limited bacteriocidal spectrum. It is an inhibitor of the A subunit of bacterial DNA GYRASE.

C12H11N2NAO3

254.22

254.067

C, 56.70; H, 4.36; N, 11.02; Na, 9.04; O, 18.88

3374-05-8

Nalidixic acid;389-08-2

3864541

White to off-white solid powder

1.331g/cm3

413.1ºC at 760mmHg

229-230ºC

203.6ºC

0.088

0

5

2

18

384

0

ROKRAUFZFDQWLE-UHFFFAOYSA-M

InChI=1S/C12H12N2O3.Na/c1-3-14-6-9(12(16)17)10(15)8-5-4-7(2)13-11(8)14;/h4-6H,3H2,1-2H3,(H,16,17);/q;+1/p-1

sodium;1-ethyl-7-methyl-4-oxo-1,8-naphthyridine-3-carboxylate

Nalidixic acid sodium salt; 3374-05-8; Nalidixic acid sodium; Baktogram; Sodium nalidixate; Nalidixate sodium anhydrous; NALIDIXATE SODIUM; Nalidixate (sodium);

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

---

Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

View More

Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

---

Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

View More

Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

---

Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

---

 (Please use freshly prepared in vivo formulations for optimal results.)