Cefonicid. A review of its antibacterial activity, pharmacological properties and therapeutic use

The Role of Five-Membered Heterocycles in the Molecular Structure of Antibacterial Drugs Used in Therapy

Five-membered heterocycles are essential structural components in various antibacterial drugs; the physicochemical properties of a five-membered heterocycle can play a crucial role in determining the biological activity of an antibacterial drug. These properties can affect the drug's activity spectrum, potency, and pharmacokinetic and toxicological properties. Using scientific databases, we identified and discussed the antibacterials used in therapy, containing five-membered heterocycles in their molecular structure. The identified five-membered heterocycles used in antibacterial design contain one to four heteroatoms (nitrogen, oxygen, and sulfur). Antibacterials containing five-membered heterocycles were discussed, highlighting the biological properties imprinted by the targeted heterocycle. In some antibacterials, heterocycles with five atoms are pharmacophores responsible for their specific antibacterial activity. As pharmacophores, these heterocycles help design new medicinal molecules, improving their potency and selectivity and comprehending the structure-activity relationship of antibiotics. Unfortunately, particular heterocycles can also affect the drug's potential toxicity. The review extensively presents the most successful five-atom heterocycles used to design antibacterial essential medicines. Understanding and optimizing the intrinsic characteristics of a five-membered heterocycle can help the development of antibacterial drugs with improved activity, pharmacokinetic profile, and safety.

Cefonicid Benzathine Salt: A Convenient, Lean, and High-Performance Protocol to Make an Old Cephalosporin Shine

Cefonicid is a second-generation cephalosporin sold under the brand name Sintocef™. It is an injectable drug obtained via a freeze-drying process and is also available for oral preparations. The high-quality standard required is very challenging to satisfy, and current production protocols are characterized by steps that are lengthy and cumbersome, making the product unattractive for the international market. Industrial R&D is constantly working on the process optimization for API synthesis, with the aim of increasing productivity and decreasing production costs and waste. We herein report a new and efficient method for the synthesis of the cefonicid benzathine salt that provides a good yield and high product stability. The double-nucleophilic and lipophilic nature of N',N″-dibenzylethylene diacetate enables the deformylation of the OH-protected group on the mandelic moiety and also enables product crystallization to occur. We demonstrate that the formyl group in the peculiar position has high reactivity, promoting an amidation reaction that deprotects a hydroxy group and generates a new C-N bond in the reaction by-product. Several amines and OH-protected groups have been studied, but none were able to replicate the excellent results of benzathine diacetate.

An Ugi Reaction/Intramolecular Cyclization/Oxidation Cascade towards Tetrazole-Linked Dibenzoxazepines

A series of tetrazole-linked dibenzo[b,f][1,4]oxazepines is synthesized through a short sequence involving an Ugi tetrazole reaction. The intermediate tetrazole undergoes a potassium carbonate mediated SNAr cyclization, followed by oxidation to afford the target tricyclic heterocyclic scaffold. The optimization, scope and limitations of this two-step and efficient methodology are investigated. A 1000-member library of tetrazole-linked dibenzo[b,f][1,4]oxazepines is generated and the physicochemical properties are analyzed. great

Controlling Pd-Catalyzed N-Arylation and Dimroth Rearrangement in the Synthesis of N,1-Diaryl-1H-tetrazol-5-amines

The Pd-catalyzed N-arylation method for the synthesis of eighteen N,1-diaryl-1H-tetrazol-5-amine derivatives is reported. By running the reactions at 35 °C, compounds were isolated as single isomers since the undesired Dimroth rearrangement was completely suppressed. Furthermore, the Dimroth rearrangement of N,1-diaryl-1H-tetrazol-5-amines was rationalized by conducting comprehensive experiments and NMR analysis as well as density functional theory (DFT) calculations of thermodynamic stability of the compounds. It was established that the Dimroth rearrangement is thermodynamically controlled, and the equilibrium of the reaction is determined by the stability of the corresponding isomers. The mechanism was investigated by additional DFT calculations, and the opening of the tetrazole ring was shown to be the rate-determining step. By maneuvering Pd-catalyzed N-arylation and the subsequent Dimroth rearrangement, two more N,1-diaryl-1H-tetrazol-5-amine derivatives were acquired, which otherwise cannot be synthesized by employing the C-N cross-coupling reaction.

Randomized trial comparing ceftriaxone with cefonicid for treatment of spontaneous bacterial peritonitis in cirrhotic patients

We compared cefonicid (2 g every 12 h) and ceftriaxone (2 g every 24 h) for their efficacy and safety in treating spontaneous bacterial peritonitis in cirrhotic patients in an open randomized clinical trial (30 patients in each group). Clinical, laboratory, and bacteriologic characteristics were similar in both groups. Ceftriaxone-susceptible strains were isolated on 44 occasions (94%), and cefonicid-susceptible strains were isolated on 43 occasions (91.5%). The antibiotic concentration in ascitic fluid/MIC ratio for ceftriaxone was > 100 throughout the dose interval (24 h), while it was lower for cefonicid (between 1 and 18). A total of 100% of patients treated with ceftriaxone, and 94% of those treated with cefonicid were cured of their infections (P was not significant). Hospitalization mortality was 37% in the cefonicid group and 30% in the ceftriaxone group (P was not significant). The time that elapsed between the initiation of treatment and the patient's death was shorter in the cefonicid group patients (5.3 +/- 3.90 days) than in the ceftriaxone group patients (11.8 +/- 9.15 days) (P < 0.05). None of the patients presented with superinfections, and only two patients treated with cefonicid and three patients treated with ceftriaxone developed colonizations with Enterococcus faecalis or Candida albicans. Ceftriaxone and cefonicid are safe and useful agents for treating cirrhotic spontaneous bacterial peritonitis, although the pharmacokinetic characteristics of ceftriaxone seem to be more advantageous than those of cefonicid.

Influence of the unbound concentration of cefonicid on its renal elimination in isolated perfused rat kidneys

The effect of variations in plasma protein binding on the renal excretion of cefonicid was assessed by using isolated perfused rat kidneys. Cefonicid exhibits preferential binding ex vivo to human serum albumin (HSA), as opposed to bovine serum albumin (BSA), and is eliminated mainly by tubular secretion, a process that was reported to be dependent on the total drug concentration. This contradicts previous studies with antimicrobial compounds and other drugs of low renal extraction in which the unbound drug concentration was shown to be the driving force for carrier-mediated tubular transport. To clarify this discrepancy, we performed perfusion studies by using 6% BSA at initial concentrations of 200 micrograms/ml (n = 6) and 20 micrograms/ml (n = 9) and in a combination of 4% BSA plus 2% HSA at initial concentrations of 200 micrograms/ml (n = 4). The excretion ratio [ER = CLR/(fu x GFR)] of cefonicid decreased with increasing unbound concentrations, whereas no apparent relationship with the total concentration was evident. At similar total concentrations of cefonicid, the renal clearance remained unchanged; the secretion clearance increased significantly in the 4% BSA-2% HSA experiments, reflecting the reduced unbound fraction and unbound drug concentration of cefonicid. The excretion ratio data were compatible with a model in which Michaelis-Menten kinetics were required to describe active transport and secretion was dependent on the unbound cefonicid concentration. As a result, changes in plasma protein binding as a result of drug interactions or disease states could significantly influence the tubular transport capability of compounds with low renal extraction.

Pharmacological properties of cephalosporins

The cephalosporins differ in the substituents attached at the 3 and/or 7 positions of the molecule. Very schematically, substitution at C3 mainly modifies the overall pharmacokinetic properties whereas substitution at position 7 influences the antibacterial characteristics. When using the more common "generation" system for classification, three generations can be distinguished on the basis of their antibacterial spectrum, potency, and their stability to beta-lactamases. The first generation cephalosporins have similar antibacterial and pharmacokinetic characteristics. C3-esterified cephalosporins (e.g. cephalothin and cephapirin) are significantly metabolized. The so-called second generation cephalosporins exhibit only minor differences with respect to the pharmacokinetic properties in contrast to the third generation cephalosporins. The apparent volumes of distribution of most cephalosporins range between seven and 20 1, indicating that they mainly stay in the extracellular space. Plasma protein binding is variable from compound to compound. Generally, the major route of elimination of most cephalosporins is via the kidney except for cefoperazone and ceftriaxone which are both excreted to a large extent by the biliary route. With the exception of cefonicid, cefotetan and cefriaxone, which have longer elimination half-lives (i.e. 4.5, 3.5 and around eight hours), all other cephalosporins have a half-life ranging from 0.5 to 2.5 hours. The pattern of adverse reactions is comparable for all the cephalosporins although there are slight differences in both the incidence and the type of reactions. The major categories of adverse reactions are gastrointestinal, dermatologic, hypersensitivity, haematologic, hepatic, renal as well as CNS effects. Alcohol intolerance (antabus-like effect) can occur when cephalosporins containing the NMTT moiety are administered concomitantly.(ABSTRACT TRUNCATED AT 250 WORDS)

The beta-lactamases of Citrobacter diversus and their hydrolysis kinetics for some structurally-related cephalosporins

We measured the kinetics of hydrolysis of various cephalosporins by the chromosomally-encoded beta-lactamases of Citrobacter diversus ULA-27. Cefonicid, cefamandole, cefatrizine and cefoperazone were all hydrolyzed but these antibiotics showed a different feature in their kinetic parameters. Moreover, cefoperazone was a non-competitive inhibitor of this type of enzyme. Cefotetan was stable to hydrolysis and behaved like a progressive inactivator. The ability of these enzymes to inactivate the reported antibiotics contributes largely to the resistance of the studied strain. We conclude that hydrolysis is the main mechanism of resistance of this strain to the new cephalosporins.

Evaluation of cefonicid use in a general hospital

Recently marketed drugs have limited experience in clinical use. Follow-up evaluation is therefore needed, particularly when these drugs are "restricted use" medicines, such as the second-generation cephalosporins. We present a follow-up of the first use of cefonicid, which was carried out after its substitution for cefuroxime in our hospital. The indication for use, dosing, therapeutic effects, and possible adverse reactions were recorded in 210 of the first 319 medical-surgical inpatients who received cefonicid. Cefonicid was administered to patients who could have been treated with free-use antibiotics on at least 128 occasions; these were cases of community-acquired pneumonia without any risk factor, urinary tract infections, acute exacerbations in patients with chronic lung disease, surgical prophylaxis, and intraabdominal infections. One fatal case of Stevens-Johnson syndrome was seen. Other recorded adverse events were two skin reactions, one tachyarrhythmia with evidence of low cardiac output, six episodes of phlebitis, and nine superinfections during treatment with cefonicid. The use of cefonicid instead of cefuroxime was associated with 20 percent cost savings; however, this study shows that optimal antibiotic prescribing may produce much greater savings.

Pharmacokinetics of cefonicid in children

The pharmacokinetics of cefonicid was studied in 17 children requiring antibiotic treatment for respiratory or urinary tract infections. After informed consent had been obtained from the parents, a single dose of cefonicid 50 mg/kg/body weight was given by intramuscular injection. The mean peak serum concentration of 212.63 micrograms/ml was reached at 1.00 h, as absorption occurred at a very fast rate with a mean constant of 3.24 h-1. Mean values for half-life, apparent volume of distribution (Vz), total body clearance (CL), and renal clearance (CLR) were 3.24 h, 0.21 l.kg-1, 16.67 ml.min-1 and 13.60 ml.min-1 respectively. There was an inverse relationship between age and Vz, whereas CL and CLR were positively correlated with age. Cefonicid concentrations in urine were many times higher than the MICs of susceptible strains of bacteria. The study demonstrated that i.m. cefonicid 50 mg.kg-1 gave serum concentrations well within the therapeutic range for susceptible bacteria, and that its pharmacokinetic properties allow single daily doses to be used to treat infections in children.

Cephalosporin, carbapenem, and monobactam antibiotics

Cephalosporin and related antibiotics are highly effective bactericidal agents of relatively low toxicity. The spectrum of activity varies with the drug but is usually broad. The first-generation cephalosporins, and especially cefazolin, are most active against sensitive staphylococci and streptococci. Most second-generation (except cefoxitin) and third-generation cephalosporins show substantial activity against Haemophilus influenzae. All cephalosporins (except cefsulodin) are active against Klebsiella, Escherichia coli, and Proteus mirabilis, whereas only the third-generation agents have pronounced activity against the other Enterobacteriaceae. Imipenem (a carbapenem) is active against essentially all pathogenic organisms, but aztreonam (a monobactam) is active against only aerobic gram-negative bacilli. Advantages associated with some of the new cephalosporins are once-daily administration and high cerebrospinal fluid levels. With the development of new cephalosporins, however, new toxicities have become apparent, and superinfections and induction of resistance have become greater problems. The cephalosporins are among the most expensive antibiotics in use today; thus, use of these expensive agents must be justified by lower toxicity, greater efficacy, or both in comparison with drugs of more reasonable cost.