头孢菌素的聚合物分析

摘要：头孢菌素是临床中最重要的一类β-内酰胺抗生素,是当前国内仿制药一致性评价的热点品种。鉴于对头孢菌素聚合 物类杂质的分析是药物杂质谱控制中的最薄弱环节,而头孢菌素的聚合反应与其3位侧链和7位侧链的结构密切相关,在对7-氨 噻肟头孢菌素的聚合物进行了专门讨论的基础上,本文根据头孢菌素7位侧链和3位侧链的特点,回顾近年来对除7-氨噻肟头孢 菌素以外的头孢菌素聚合物分析取得的进展,归纳总结它们的聚合反应特性、聚合物特性等,进而形成对头孢菌素聚合物分析 的完整策略。     

Structure-binding relationship and binding sites of cephalosporins in human serum albumin.

The binding of some cephalosporins to human serum albumin (HSA) was studied by an ultrafiltration technique. Changes in C-3 side chain resulted in marked changes in the binding to HSA, but changes in C-7 side chain did not. Cephalosporins were classified into three groups by C-3 side chain: (i) Cationic side chain with low affinity for HSA; (ii) anionic side chain with high affinity for HSA; (iii) non ionized side chain, in which binding to HSA was dependent on lipophilicity. These findings suggest that electrostatic and hydrophobic forces play a role in the binding affinity of cephalosporins for HSA. The binding of cephalosporins with high HSA affinity was displaced significantly by warfarin but not by phenylbutazone, L-tryptophan, or diazepam. The interaction of the cephalosporins with high affinity for HSA with chemically modified HSA was investigated to clarify the amino acid residues of HSA involved in the cephalosporin binding sites. The binding of the cephalosporins decreased remarkably with the modification of the tyrosine residues. These results suggest that the binding site of cephalosporins is located in the vicinity of warfarin binding site rather than benzodiazepine binding site and that tyrosine residues are involved in the cephalosporin binding site.     

Synthesis and activity of 3-(isoxazolin-5-yl)- and 3-(isoxazol-4-yl)cephalosporins.

The 1,3-dipolar cycloaddition of nitrile oxide with 3-vinylcephalosporin provided diastereomeric isomers of 3-(isoxazolin-5-yl)cephalosporin. Cycloaddition of nitrile oxide with 3-(dimethylamino-vinyl)cephalosporin gave 3-(isoxazol-4-yl)cephalosporin. These semisynthetic cephalosporins with an aminothiazole in the C-7 side chain showed moderate antibacterial activities.     

Correlation between structure and biological properties of cephalosporins: the discovery of ceftriaxone

A research programme on cephalosporins was conducted in the author's laboratory with the aim of creating compounds with improved antibacterial and pharmacokinetic properties. In the first phase of this programme, great attention was paid to the study of how the structure of a 3-heterocyclic-thiomethyl side chain is capable of influencing antibiotic activity within a large series of model compounds possessing the same acyl side chain (2-thienylacetyl) as cephalothin. Several structural and physico-chemical features of the heterocyclic thiols used and the corresponding cephalosporins were correlated with in vitro and in vivo activity. As a result of these studies, the enolic 2-methyl-6-hydroxy-5-oxo-as-triazine-3-thiol was identified as the most interesting substituent, since the corresponding cephalosporin showed a valuable resistance breakthrough against several cephalothin-resistant Proteus strains. Consequently, further studies involving the use of different acyl side chains were performed. The introduction of the basic 2-(2-amino-4-thiazolyl)-2-(Z)-methoxyimino-acetyl side chain finally led to ceftriaxone, which has a very long elimination half-life of 8 hours, high beta-lactamase stability and extremely high chemotherapeutic efficacy against a broad spectrum of Gram-positive and Gram-negative pathogens. Owing to these properties, ceftriaxone is the first beta-lactam antibiotic suitable for once-daily administration.     

Synthesis and activity of potent 3-(isoxazolidin-5-yl)- and 3-(isoxazolidinium-5-yl)cephalosporins.

The syntheses and in vitro antibacterial activities of 3-(isoxazolidin-5-yl)- and 3-(isoxazolidinium-5-yl)cephalosporins are described. 1,3-Dipolar cycloaddition of 3-vinylcephalosporin with nitrone gave diastereomeric isomers of 3-(isoxazolidin-5-yl)cephalosporin. The antibacterial activities of 3'-(S)-isomers were superior to those of 3'-(R)-isomers. The quaternarization of isoxazolidine ring increased the antibacterial activity. Among them, compound 10b with a hydroxyimino group in the C-7 side chain showed potent activities against staphylococci and compound 10f with an N-hydroxypyridone exhibited an excellent antipseudomonal activity.     

Cefazolin tolerance does not predict ceftriaxone hypersensitivity: unique side chains precipitate anaphylaxis

A 48-year-old woman with a questionable history of an unspecified ceftriaxone allergy was treated with cefazolin for surgical antibiotic prophylaxis. After she tolerated cefazolin therapy for 4 days, the medical staff concluded that her allergy history was inaccurate, and she was treated with intravenous ceftriaxone for suspected nosocomial pneumonia. Approximately 10 minutes after the start of the infusion, the patient experienced anaphylaxis. Initial symptoms of oral angioedema and laryngopharyngeal constriction progressed to dyspnea, tachypnea, hypotension, and tachycardia, all of which quickly resolved after immediate treatment with hydrocortisone, diphenhydramine, and epinephrine. Skin testing with cefazolin, cefepime, and ceftriaxone revealed that the likely allergic determinant mediating the patient's hypersensitivity reaction was the unique ceftriaxone R2 side chain and not the beta-lactam ring, which initially was suspected by the physician. Immunoglobulin E-mediated hypersensitivity reactions to cephalosporins may occur due to antibody complexes with the beta-lactam ring or various cephalosporin side chains. Misconceptions regarding the nature of cephalosporin allergies complicate antibiotic selection for patients with questionable allergy histories and may lead to inappropriate drug reexposure and anaphylaxis. Detailed understanding of the antigenic determinants that mediate hypersensitivity reactions is essential for clinicians to avoid type 1 reactions in patients with a suspected allergy to cephalosporins.     

Studies on cephalosporin antibiotics. I. Synthesis, antibacterial activity and oral absorption of new 3-(O-substituted)-7 beta-[D-alpha-amino-alpha-(4-hydroxyphenyl)acetamido]cephalosporins

The synthesis, antibacterial activity and oral absorption of new 7 beta-[D-alpha-amino-alpha-(4-hydroxyphenyl)acetamido]cephalosporins (1) with various O-substituents at the C-3 position of a cephalosporin nucleus are described. Of these, the cephalosporins (1b-1e) having an alkoxycarbonylmethoxy group at the C-3 position showed good oral absorption in rats as well as potent activity against Gram-positive bacteria. The structure-activity relationships of 1 are also presented.     

Hypersensitivity reactions to cephalosporins

At present, cephalosporins represent one of the most prescribed classes of antibiotics. Although allergic reactions have been estimated to be infrequent, the number of reactions to cephalosporins is increasing due to their wide use. Cross-reactivity with penicillins has mainly been evaluated in patients with penicillin allergy. It is higher between first- and second-generation cephalosporins with the same or similar side chain than between cephalosporins with different side chains. Unlike penicillins, cephalosporin haptens or determinants have not been defined, and therefore the diagnosis is complicated. Nevertheless, skin tests with cephalosporins are useful in the evaluation of several allergic reactions. Although more studies are necessary, a negative result in skin testing to penicillin and cephalosporins with different side chains seems to be a good predictor of tolerance, and could be used in select cases.     

In vitro biological activities of 6-isosteric penicillins and 7-isosteric cephalosporins

Antibiotic and penicillinase inhibitor activities of various penicillin and cephalosporin analogs are reported. The compounds include C-6 penicillin and C-7 cephalosporin carbon, oxygen and sulfur analogs obtained by replacing the NH of the amide side chains with CH2, O and S, respectively. In almost all cases, analogs were considerably less active than the standard compounds (benzylpenicillin and cephalothin). However, some of the analogs act as penicillinase inhibitors.     

青霉素过敏患者合理使用头孢菌素研究进展

头孢菌素与青霉素母核的相似性造成了头孢菌素与青霉素以及头孢菌素间的交叉过敏,但α环和侧链的差异使交叉过敏的发生率缺乏足够的指导意义。综合考虑多个因素对青霉素过敏患者使用头孢菌素的影响,可以更有效的避免患者对头孢菌素过敏反应和过敏性休克反应的出现。本文综述了药物过敏的分类、头孢菌素侧链和交叉过敏间的关系,青霉素过敏患者使用头孢菌素指导原则、以及各地区间头孢菌素皮试方法对青霉素过敏患者使用头孢菌素的意义及临床应用价值。     

Studies on monocyclic beta-lactam antibiotics. II. Synthesis and antibacterial activity of 3-acylamino-2-azetidinone-1-oxysulfonic acids

The synthesis and in vitro antibacterial and beta-lactamase inhibitory activity of the 2-azetidinone-1-oxysulfonic acids having a substituent at C-4 position of the beta-lactam ring are described. The influence of C-4 substituents on the antibacterial activity was examined for the compounds having alpha-ureidoacetyl or alpha-oxyiminoacetyl group as acyl side chain at C-3 position. The antibacterial activity is correlated with the C-4 substituents and acyl side chain. Especially, 4(R)-methyl substituted derivatives exhibited excellent activity against Gram-negative bacteria and 4-dimethyl substituted derivatives exhibited strong activity against resistant Gram-negative bacteria except for Pseudomonas aeruginosa. 39 and 40 showed strong inhibitory activity against cephalosporinase of Enterobacter cloacae H-27.     

Benzothiopyranoindazoles, a new class of chromophore modified anthracenedione anticancer agents. Synthesis and activity against murine leukemias

The synthesis of the benzothiopyranoindazoles, a new class of chromophore modified anthracenediones related to mitoxantrone, is described. In this structural class the quinone moiety, which is believed to be responsible for the cardiotoxicity of the anthracyclines, has been designed out. The synthesis of the benzothiopyranoindazoles was carried out by a multistep sequence from requisite 1-chloro-4-nitro-9H-thioxanthen-9-one precursors. Reaction with a monoalkylhydrazine gave a 5-nitrobenzothiopyranoindazole adduct, which was catalytically reduced to a corresponding C-5 anilino intermediate. Alkylation of 7 with a requisite X(CH2)nNR1R2 (X = Cl, Br; R1, R2 = H, alkyl, acyl; n = 2,3) provided target "two-armed" benzothiopyranoindazoles or A-ring methoxy and/or side chain acyl intermediates, which could be converted to 3 by appropriate deprotection methodologies. Alternatively, certain target compounds 3 were synthesized by reaction of 7 with appropriately functionalized glycine precursors under Schotten-Bauman or BOP chloride condensation conditions to provide C-5 acylamino intermediates, followed by Red-Al reduction and deprotection steps. Described also is the synthesis of selected benzothiopyranoindazole congeners with proximal acylamino side chains at C-5 and B-ring sulfone functionality at S-6. Potent activity was demonstrated against murine L1210 leukemia in vitro (IC50 = 10(-7)-10(-9) M) as well as against P388 leukemia in vivo over a wide range of structural variants. In general, activity against the P388 line was maximized by (a) a basic side chain at N-2 and a dibasic side chain at C-5 with primary or secondary distal amine substitution, (b) certain patterns of A-ring hydroxylation with 8-OH and 9-OH most favorable, and (c) sulfide oxidation state at S-6. Besides having curative activity against the P388 line, the more active compounds were curative against murine B-16 melanoma in vivo. On the basis of their exceptional broad-spectrum in vivo anticancer activity, selected compounds in this series have been chosen for development toward clinical trials.     

HIV epitope-peptides in aluminum adjuvant induced high levels of epitope-specific antibodies

Some neutralizing epitopes on HIV-1 envelope proteins were shown to induce antibodies that could effectively inhibit the infection of different HIV-1 strains in vitro. But only very low levels of antibodies to these epitopes were determined in the HIV-1 infected individuals. In this study, the aluminum (alum) adjuvant to increase the immunogenicity of the neutralizing epitopes was used. Three epitope-peptides [C-(ELDKWAG)4, C-(RILAVERYLKD-G)2 and C-(GPGRAFY)2], which contain three epitopes (ELDKWA, RILAVERYLKD, GPGRAFY) from the HIV-1 Env proteins, were synthesized and conjugated to carrier protein keyhole limpet hemocyanin (KLH). The epitope-vaccines C-(ELDKWAG)4-KLH and C-(RILAVERYLKD-G)2-KLH in alum induced high levels of epitope-specific antibodies recognizing the epitopes from epitope-peptides C-(ELDKWAG)4 and C-(RILAVERYLKD-G)2, as well as the gp41 C-domain peptides P2 [C-TSLIHSLIEESQNQQEKNEQELLELDKWA (aa 646-674)] and P1 [LQARILAVERYLKDQQL (aa 583-599)] and the recombinant soluble gp41 (rsgp41) bearing both epitopes (antibody titer in rabbit sera was 1:12800-25,600 dilution). Immunoblotting analysis demonstrated that the antibodies in both antisera bound to rsgp41, indicating that both antibodies recognized the natural epitopes on rsgp41 protein. The epitope-vaccines C-(GPGRAFY)2-KLH induced moderate GPGRAFY epitope-specific antibody response with a titer of 1:6,400. In contrast, as it was demonstrated in previous studies, the immunization with rgp160 induced weak antibody response to these three epitopes (titer of 1:400-1600). This suggests that epitope-peptides conjugated to KLH when infected with alum significantly increases immunogenicity of gp41 neutralizing epitopes providing a hope for the development of an HIV-1 vaccine.     

青霉素单克隆抗体研究——青霉素类抗生素交叉过敏反应及其抗原决定簇

利用酶联免疫吸附试验研究4个青霉素单克隆抗体和5种不同侧链青霉素细胞色素C结合物作用,探讨青霉素交叉过敏反应及其抗原决定簇.实验证明青霉素过敏反应抗原决定簇——青霉噻唑基团,有二个结合位点,一是可被D8单克隆抗体所识别的青霉素侧链,一是可被D44、D7等单抗识别的青霉素β-内酰胺环破裂后与载体上氨基结合形成新位点.我们认为新位点是青霉素类抗生素间的交叉过敏反应的重要位点.头孢噻吩不具有四氢味喃环而其与细胞色素C结合物与单抗D8、D44、D7亲和力仅弱于BPO_4—Cy,又从竞争性抑制酶联免疫吸附试验结果亦表明四氢呋喃环不是一个结合位点,头孢噻吩和青霉素间交叉反应由于有共同新结合位点是重要因素,所以我们推测青霉素及头孢霉素间可能存在着交叉过敏反应.     

Aminothiazolylglycyl derivatives of carbacephem antibiotics. II. Synthesis and antibacterial activity of novel aminothiazolyl cephem compounds with hydroxypyridone moiety

The synthesis and antimicrobial activity of novel carbacephem antibiotics which have amido moiety of (S)-aminothiazolylglycyl side chain are described. Among them, the compound having 5-hydroxy-4-pyridon-2-carboxyl group (KT-4697) showed exceptionally strong activity against Pseudomonas aeruginosa as well as Gram-negative bacteria. A cephalosporin with this acyl group namely KT-4788 with methylpyridiniumthiomethyl group at C-3 was found to be the most active against Gram-positive and Gram-negative strains including P. aeruginosa.     

IgE-mediated hypersensitivity to cephalosporins

Like penicillins, cephalosporins may cause IgE-mediated reactions such as urticaria, angioedema, and anaphylactic shock, which occur because of sensitization to determinants shared with penicillins or to unique cephalosporin haptens. In particular, side-chain structures may be responsible for selective sensitization or cross-reactivity. For this reason, individual free cephalosporins are usually employed in skin testing, in addition to the classic penicillin reagents. Cephalosporin skin tests are sensitive in diagnosing immediate hypersensitivity to these betalactams. As far as in vitro tests are concerned, IgE assays for cephalosporins, specifically sepharose-radioimmunoassays, are a potentially useful tool in evaluating immediate reactions and could be used as complementary tests. In selected cases displaying negative results in both skin tests and IgE assays, a graded challenge with the implicated cephalosporin can be performed. Cephalosporin IgE-mediated hypersensitivity may be a transient condition; therefore, allergologic exams should be repeated in patients with negative initial allergologic work-ups, including challenges. Performing allergologic tests with cephalosporins other than the culprit, as well as with penicillin reagents, allows the identification of cross-reactivity with penicillins, selective responses, or cross-reactivity among cephalosporins. In the latter group, cross-reactivity is more frequently related to R1 than to R2 side-chain recognition. In assessing the selectivity of the response, negative results in skin testing with cephalosporins other than the responsible one appear to be a reliable indicator of tolerability.     

头孢菌素类抗生素结构修饰的研究

细菌的耐药性问题日益严峻,给临床治疗带来极大困难。研发新型抗耐药菌药物成为目前的研究热点。头孢菌素作为重要的抗生素药物,在筛选新抗生素困难重重的情况下,对其进行适当的结构修饰成为创制新药的有效途径。本文简单介绍了头孢菌素类构效关系,并对头孢菌素分子结构中的C-2、C-3、C-7等部位的修饰改造以及相关母核来源进行了综述。     

Orally absorbable cephalosporin antibiotics. 1. Structure-activity relationships of benzothienyl- and naphthylglycine derivatives of 7-aminodeacetoxycephalosporanic acid

A structure-activity relationship study of a number of orally absorbed cephalosporins together with their syntheses is described. These new cephalosporins are benzothienyl- and naphthylglycine derivatives of 7-aminodeacetoxycephalosporanic acid. Several different synthetic methods for the glycine side chains, their protection, and the final acylations are reported. Several of these analogues were more active than cephalexin both in vitro and in vivo against commonly encountered Gram-positive bacteria. (R)-7-(3-Benzothienylglycylamido)-3-methyl-3-cephem-4-carboxylic acid (1R) has emerged as a potent antibacterial agent and is currently undergoing preclinical evaluation.     

Studies on cephalosporin antibiotics. II. Synthesis, antibacterial activity and oral absorption of 3-alkoxycarbonylmethoxy-7 beta-[(Z)-2-(2-aminothiazol-4-yl)-2-(O-substituted oxyimino)-acetamido]cephalosporins

The synthesis, antibacterial activity and oral absorption in rats of 3-alkoxycarbonyl-methoxy-7 beta-[(Z)-2-(2-aminothiazol-4-yl)-2-(O-substituted oxyimino)acetamido]cephalosporins (1) are described. In this cephalosporin series, 7 beta-[(Z)-2-(2-aminothiazol-4-yl)-2-(carboxy-methoxyimino)acetamid o] cephalosporins (1b, 1i and 1j) with a lower alkoxycarbonylmethoxy group at the C-3 position of a cephem nucleus exhibited not only potent activity against Gram-negative bacteria but also good oral absorption in rats. Structure-activity relationships of 1 are also presented.     

New cephalosporins with 7-acyl groups derived from beta-ketoacids. II. Further modifications of 7-(3-oxobutyrylamino)-cephalosporins.

New cephalosporins modified in the acyl part of 7-(3'-oxobutyrylamino)cephalosporins (1), which have been described in the preceding paper, were synthesized by thiolation at the 2'- or the 4'-position, or by transforming the 3'-oxo group into a 3'-imino group. The most active compound in vitro was 3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-7-(4-methylthio-3-oxobutyrylamino)ceph-3-em-4-carboxylic acid (7c), which showed superior in vitro activity against Gram-positive and Gram-negative bacteria compared to the parent cephalosporin (1b) with the same 3-substituent. The ED50 value for 7c, however, was essentially equal to that of 1b in mice infected with Escherichia coli O-111.