Prodrug intended for the treatment of infections by bacteria resistant to antibiotics of the β-lactam family

Abstract

The present invention relates to the field of antibacterial therapy intended to combat antibiotic-resistant infections. More particularly, the present invention relates to prodrugs that enable the local and specific inhibition of bacterial infections caused by bacteria resistant to antibiotics of the β-lactam family. This prodrug comprises an antibacterial component from a new therapeutic class, which is bound to a bait molecule containing a functional group that can be cleaved by β-lactamases as defined in the classification of Ambler (1980) and Bush and Jacoby (2010). The antibacterial component is masked and thus inactive in the prodrug state, and upon cleavage of the prodrug in situ by pathogenic bacteria, it resumes its native structure and antibacterial properties.

Description

Technical Field

[0001] The present invention relates to the field of antibacterial therapy intended to combat antibiotic-resistant infections. More particularly, the present invention relates to prodrugs that enable the local and specific inhibition of bacterial infections caused by bacteria resistant to antibiotics of the β-lactam family. This prodrug contains an antibacterial component from a new therapeutic class, which is bound to a bait molecule containing a functional group that can be cleaved by β-lactamase as defined in the classification of Ambler (1980) and in the classification of Bush and Jacoby (2010). The antibacterial component is derived from trans-cinnamaldehyde and is masked, and thus is inactive in the prodrug state. When the prodrug is cleaved in situ by pathogenic bacteria, its native structure and antibacterial properties are restored.

Background Art

[0002] The fight against bacterial infections is a concerning public health issue when dealing with multi-drug resistant bacteria. In fact, many bacteria have developed resistance mechanisms to conventional antibiotics, particularly those of the β-lactam family. To treat these infections, second-generation antibiotics are administered, but these second-generation antibiotics have side effects. Systemic use (i.e., non-local and non-specific) also leads to the emergence of new resistance to new molecules.

[0003] In particular, strategies for targeting antibacterial molecules at the site of infection by antibiotic-resistant bacteria have been proposed by exploiting the resistance mechanisms deployed by the bacteria that are the target of treatment. Such an approach has been described by Evans et al. (J. Med. Chem 2019, 62, 4411-4425) and consists of prodrugs that can be activated by β-lactamases produced by resistant bacteria. In this way, the conventional antibiotic molecule ciprofloxacin is chemically linked to a β-lactam motif recognized by the bacteria and cleaved by the bacteria to release the antibiotic molecule. However, the specificity of this prodrug can be limited by the fact that the molecular structure of the antibiotic is in its "active" form within the prodrug. That is, the prodrug exhibits antibiotic activity, albeit to a lesser extent, even before being cleaved by β-lactamase. This limits the specificity of the action of the prodrug against multidrug-resistant bacteria, but this aspect is essential to avoid systemic exposure and the opportunity to generate resistance mechanisms in bacteria that were not previously multidrug-resistant. This system provides a localized antibacterial effect at the site of infection but does not solve the problem of antibiotic resistance.

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a genuine need for new treatment strategies for treating infections caused by antibiotic-resistant bacteria. Solutions to address this need must incorporate (1) new treatment targets and (2) specific local action to avoid systemic exposure and the development of resistance.

Means for Solving the Problems

[0005] The present inventors propose a new treatment strategy in the fight against antibiotic-resistant bacteria. This approach is based on the antibacterial effect of small molecules targeting new molecular targets, and the mechanism of action is not countered by conventional defense or resistance systems generated by bacteria, such as specific molecules derived from essential oils. However, since these molecules are unstable and have low bioavailability, an innovative delivery system needs to be associated with them so that the therapeutic solution according to the present invention takes the form of a prodrug. This approach consists of a prodrug that enables local delivery of the active molecule only to the site of interest (the infected site containing the resistant bacteria) due to an enzymatic reaction specific to multidrug-resistant bacteria that can cleave the prodrug. Thereby, harmful systemic effects of the active ingredient are prevented.

[0006] Accordingly, a first object of the present invention is a prodrug intended for use in the treatment of infections of bacteria resistant to antibiotics of the β-lactam family, comprising an antibacterial component linked to a bait molecule containing a functional group cleavable by β-lactamase, of the formula (I):

[0007] [Chemical formula]

[0008] (wherein, X is either absent or a spacer group selected from a phenylene, alkenylene, or alkynylene group. R 1 is a group selected from alkyl, alkylsulfonylethyl, or alkylaminoethyl, for example, methyl, methylsulfonylethyl, or dimethylaminoethyl, R 2 is a group selected from methyl, 2,2,2-trifluoroethyl, R 3 is a masked antibacterial component, and the masked active ingredient corresponds to a structure of trans-cinnamaldehyde lacking an aldehyde functional group or one of the variants of this structure having retained antibacterial activity, R4 is a β-lactam group.) It relates to a prodrug characterized by corresponding to

[0009] The second object of the present invention relates to a pharmaceutical composition comprising the prodrug according to the present invention and at least one pharmaceutically acceptable excipient.

[0010] The third object of the present invention relates to the use of the prodrug according to the present invention in the treatment of infections caused by bacteria resistant to antibiotics of the β-lactam family.

Advantages of the Invention

[0011] The present invention differs from existing solutions by the choice of the antibacterial active ingredient and by the fact that the active ingredient is masked within the prodrug (and thus inactivated in the prodrug form). In fact, the inventors have developed an approach to utilize the antibacterial properties of small molecules, such as those derived from essential oils (EOs), whose instability and low bioavailability have conventionally been obstacles to therapeutic use. The latter are known for their antibacterial activity and novel mechanism of action and are less likely to induce resistance in bacteria. Thus, the object of the present invention is to make available a new class of antibacterial (pro)drugs that are effective and safe (do not induce new resistance) for treating infections caused by β-lactam-resistant bacteria.

[0012] The drug in question is in the form of a prodrug containing an antibacterial component derived from a small molecule having an aldehyde functional group; this functional group is exposed to multiple rapid modification mechanisms by the patient's metabolism, resulting in a decrease in the bioavailability of the small molecule. To ensure access to the site of infection, it needs to be incorporated into a molecular construct with appropriate stability, water solubility, and bioavailability. Thus, the active ingredient is modified by conjugation with a bait molecule. Another advantage of this system is that it masks the activity of the active ingredient but ensures its release in the presence of bacteria resistant to β-lactam family antibiotics. Once released, the molecule regains its active form and antibacterial properties. Thus, delivery of the active ingredient targets the site of infection and avoids the side effects and the risk of development of resistance associated with systemic distribution of the antibacterial agent.

[0013] Release of the active ingredient depends on the action of resistant bacteria. In fact, the prodrug contains a group recognized by β-lactamase secreted by pathogenic bacteria with resistance, and β-lactamase catalyzes the cleavage of the β-lactam unit, which is the bait molecule unit of the prodrug. Disintegration of the unit releases the antibacterial component and delivers the active molecule to the site of infection. Thus, the prodrug acts as a Trojan horse because the bacteria activate a defense system (secretion of β-lactamase-type enzymes) to release antibacterial molecules that destroy and / or inhibit it.

[0014] More specifically, the β group and the active ingredient (R 3Between the (group) and the prodrug, the prodrug contains an N / O-acetal-oxycarbonyl group linked to an X spacer group. It is this N / O-acetal-oxycarbonyl group that ensures the incorporation and masking of the active ingredient, as well as the release of the active ingredient after the disintegration of the prodrug caused by the action of the target enzyme. This is a unique feature of the prodrug structure of the present invention based on the innovative characteristics of the present invention related to similar prodrug molecules in the prior art. That is, the release is efficient, but the prodrug is stable against spontaneous hydrolytic disintegration in the absence of the target enzyme. Furthermore, this property ensures that the prodrug cannot exert its inherent antibiotic effect because the structure of the active ingredient is not restored in the absence of cleavage. These two properties make it possible to provide the clinical use of the prodrug according to the present invention.

[0015] Therefore, the system according to the present invention depends on the local, immediate and specific action of antibacterial molecules from a new therapeutic class and is less likely to induce new resistance. An example of such a molecule is trans-cinnamaldehyde, which is the active ingredient in cinnamon essential oil.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0017] The first object of the present invention is a prodrug intended for use in the treatment of infections of bacteria resistant to antibiotics of the β-lactam family, comprising an antibacterial active ingredient linked to a bait molecule containing a functional group cleavable by β-lactamase, of formula (I):

[0018] [Chem.] (wherein, X is absent or is a spacer group selected from a phenylene, alkenylene, or alkynylene group. R 1 is a group selected from alkyl, alkylsulfonylethyl, or alkylaminoethyl, for example, methyl, methylsulfonylethyl, or dimethylaminoethyl, R 2 is a group selected from methyl, 2,2,2-trifluoroethyl, R 3 is a masked antibacterial component, and the masked active component corresponds to one of the structures of trans-cinnamaldehyde lacking an aldehyde functional group or a variant of a structure having retained antibacterial activity, R 4 is a β-lactam group) relates to a prodrug characterized by corresponding to

[0019] The term "prodrug" refers to a drug precursor. This is an inactive / low-active form of a molecule that is metabolized in vivo into an active metabolite. In the present invention, the prodrug consists of a masked antibacterial component and a bait molecule. Thus, the antibacterial component is a metabolite.

[0020] The active ingredient is a small molecule drug having antibacterial properties. The active ingredient is masked in the prodrug, i.e., in the inactive form. Such active ingredients may be derived from various types of plants including plants or lichens, particularly essential oils, or animals, particularly marine animals.

[0021] In a preferred embodiment of the present invention, the antibacterial active ingredient is derived from one of EOs having known antibacterial properties, trans-cinnamaldehyde shown below, or a variant thereof. "Trans-cinnamaldehyde variant" means a molecule having the same structure as cinnamaldehyde, showing similar, identical or excellent antibacterial activity, and / or imparting high stability to prodrugs. Such variants can be substituted, in particular, in the phenyl unit, for example, H can be substituted with an alkylamino group such as methoxy, ethoxy, dimethylamino, or an acylamino group.

[0022]

Chemical formula

[0023] Within the prodrug, the active ingredient is inactivated by masking its aldehyde functional group. This modification has the following two functions: enabling binding to the bait molecule and masking (temporarily suppressing) the antibacterial activity of the active ingredient while in the prodrug form.

[0024] In the context of the present invention, masking is achieved by converting the aldehyde functional group to an N / O acetal, and the nitrogen atom of the N / O acetal is acylated (more precisely, "oxycarbonylated") to give the acetal greater stability against spontaneous hydrolysis (decay), and when the bait portion of the prodrug is activated by the target β-lactamase, it allows the release of this oxycarbonylated N / O acetal as a carbamate (a good leaving group). Then, "R" 3 represents a phenyl-vinyl unit.

[0025] "Bait molecule" in the meaning of the present invention means a group that can be recognized by bacteria and induce the activation of the bacteria's defense function against β-lactam family antibiotics. These defense functions consist of secreting an enzyme that can cleave the β-lactam nucleus present in antibiotics of this family.

[0026] The bait molecule according to the invention is a R that is recognized by bacteria that are resistant to β-lactams. 4 This R 4 The group is a β-lactam group that mimics the presence of an antibiotic. As explained above, recognition of this group acts as a signal to induce the secretion of β-lactamase by the bacterium, which acts in defense. Furthermore, the bait molecule comprises a central group of formula (I) (N / O-acetal-oxycarbonyl group) and optionally a spacer group X.

[0027] A particularly innovative aspect of the present invention resides in the structure of the cleavable functional group (corresponding to the central N / O-acetal-oxycarbonyl group of formula (I)), which has three functions: (i) the ability to bind an active ingredient to the β-lactam group; (ii) the ability to mask the antimicrobial activity of the active ingredient by incorporation into an N / O-acetal-oxycarbonyl unit; and (iii) Activation of antibacterial activity by cleavage of the β-lactam group following secretion of β-lactamase by bacteria, followed by self-collapse of the structure, resulting in the release of the active ingredient in a restored active form with new class of antibiotic properties. In fact, it is worth noting that the cleavable group has the property that the active ingredient modified to synthesize the prodrug can regain its natural form and antibacterial properties after release. Here, the active ingredient is, as shown in formula (I), R 3 The aldehyde functionality of the active ingredient is reformed in situ. This mechanism of action is shown in Figure 3.

[0028] In a preferred embodiment of the present invention, the β-lactam group (R 4 The group (β-lactamase) is derived from a cephalosporin, penicillin or carbapenem. The group is cleavable by a β-lactamase, which may be a carbapenemase.

[0029] Many R 4The base is described in the literature and can be identified by a person skilled in the art. A specific example is cephalothin.

[0030]

Chem.

[0031] R 4 The group is more generally represented by the following formula (II):

[0032]

Chem.

[0033] (wherein R 7 is selected from alkyl, benzyl, substituted or unsubstituted aryl groups) can be represented.

[0034] Examples of specific R 7 groups are shown below.

[0035]

Chem.

[0036] The spacer group X modulates the properties of the prodrug according to the choice of the X group and the active ingredient associated with the prodrug. Its presence is optional. In the configuration where the X group is absent, the R 4 group is directly bonded to the N / O-acetal-oxycarbonyl group.

[0037] Examples of the prodrugs according to the present invention are the OSTA-1, OSTA-1b, OSTA-5, OSTA-6 and OSTA-7 molecules shown below.

[0038]

Chem.

[0039] The second object of the present invention relates to a pharmaceutical composition comprising the prodrug defined above and at least one pharmaceutically acceptable excipient.

[0040] The third object of the present invention relates to the use of the prodrug defined above in the treatment of infections by bacteria resistant to antibiotics of the β-lactam family.

[0041] Infections by bacteria resistant to β-lactam antibiotics are mainly caused by Gram-negative bacteria capable of producing β-lactamase. However, some Gram-positive bacteria such as MRSA can also produce β-lactamase.

[0042] The prodrug according to the present invention is particularly aimed at the following.

[0043] - Gram-negative bacteria belonging to one of the following families: Moraxellaceae, Legionellaceae, Enterobacteriaceae, Pseudomonadaceae, Alcaligenaceae, Sphingomonadaceae, Pasteurellaceae, Neisseriaceae, Pasteurellaceae, Flavobacteriaceae, Bacteroidaceae, Fusobacteriaceae, Burkholderia cepacea, Cronobacter malonaticus, Cronobacter sakazakii, Helicobacter pylori, Micrococcus luteus, Prevotella, Proteus mirabilis, Proteus vulgaris G, Salmonella enteritidis G-, Salmonella enterica serovar typhi, Salmonella typhimuriu, Salmonella enterica serovar paratyphi A, Vibrio fluvialis (MDR), Vibrio parahaemolyticus, and Acinetobacter baumannii;

[0044] - A Gram-negative bacterium belonging to one of the genera shown below: Klebsiella, Serratia, Citrobacter, Salmonella, Shigella, Proteus, Haemophilus, Campylobacter, Legionella, Sphingomonas, Moraxella, Kingella, Pasteurella, Capnocytophaga, Neisseria, Bacteroides, Enterobacter, Pseudomonas, Fusobacterium, Achromobacter, Escherichia, and Acinetobacter;

[0045] - A Gram-negative bacterium belonging to one of the species shown below: Klebsiella pneumoniae, Klebsiella oxytoca, Acinetobacter baumannii, Acinetobacter calcoaceticus, Serratia marcescens, Citrobacter freundii, Citrobacter koseri, Haemophilus influenzae, Haemophilus parainfluenza, Campylobacter jejuni, Campylobacter coli, Legionella pneumophila, Legionella longbeachae, Legionella bozmanii, Legionella micdadei, Enterobacter cloacae, Escherichia coli, Escherichia hermannii, Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas putida, Pseudomonas stutzeri, Achromobacter xylosoxidans, Achromobacter denitrificans, Sphingomonas paucimobilis, Moraxella catarrhalis, Kingella kingae, Pasteurella multicida, Capnocytophaga canimorsus, Neisseria gonorrhoeae, Neisseria actamica, and Bacteroides fragilis; - In particular, Pseudomonas aeruginosa and Acinetobacter baumannii (especially, Acinetobacter baumannii 5377 or mucoid Acinetobacter baumannii).

[0046] - The following Gram-positive bacteria: Family: Staphylococcaceae, Micrococcaceae, Streptococcaceae, Enterococcaceae, Bacillaceae, Clostridiaceae, Listeriaceae, and Corynebacteriaceae; Genus: Staphylococcus, Micrococcus, Streptococcus, Enterococcus, Bacillus, Clostridium, Listeria, and Corynebacterium; Species (example): Staphylococcus aureus, Staphylococcus epidermitis, Staphylococcus saprophyticus, Micrococcus luteus, Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus pneumoniae, Streptococcus viridans, Enterococcus faecalis, Enterococcus faecium, Bacillus anthracis, Clostridium difficile, Listeria monocytogenes, and Corynebacterium diphteriae.

[0047] - Other non-gram-staining bacteria: Family: Mycobacteriaceae; Genus: Mycobacterium; Species: Mycobacterium tuberculosis, Mycobacterium leprae, Mycobacterium abscessus, and Mycobacterium ulcerans.

[0048] These infections affect, in particular, the digestive tract, urinary tract, pulmonary tract, or skin and mucous membranes and can involve specific organs or be systemic. The prodrugs according to the invention can be used to treat all of these infection forms.

[0049] Examples of infectious diseases (with or without co - morbidities such as genetic factors, immunosuppression) for which the molecules according to the invention are particularly attractive are shown below. Respiratory tract infections (with or without co - morbidities): pneumonia, HAP, VAP, tuberculosis, rhinosinusitis, cystic fibrosis; blood or blood - borne infections: bacteremia, sepsis; urinary tract infections: cystitis, pyelonephritis; skin and soft tissue infections: abscess, swelling, impetigo, non - healing wounds, necrotizing infections; surgical site infections; infections associated with prostheses, medical devices (catheters, tubes, etc.); gastrointestinal infections; sexually transmitted infections; infections of the central or peripheral nervous system, heart, eyes, ears, mouth, bones and joints.

[0050] The present invention will be better understood by reading the following examples, which are provided by way of illustration and are in no way intended to limit the scope of the invention.

Examples

[0051] Example 1: Synthesis of Compound A (OSTA - 1) The synthesis protocol of the OST1 prodrug molecule involves five steps and two auxiliary steps. This is shown in Figure 1.

[0052] Example 2: Functional analysis of the OSTA - 1 molecule A: In vitro cleavage of the OSTA - 1 molecule The cleavage of the OSTA - 1 prodrug was tested in vitro by contacting it with β - lactamase in an aqueous saline medium.

[0053] Experimental conditions: The cleavage test is carried out in a phosphate - buffered saline (PBS) saline buffer at pH 7.0. The OSTA - 1 molecule is added at a concentration of 100 μM together with commercially available β - lactamase at a concentration of 1 unit / mL. Incubation is carried out at 37°C. Then, the appearance of free trans - cinnamaldehyde in the medium is monitored by UV absorption at 285 nm. The results are shown in Figure 2.

[0054] The release of the active ingredient (in this case, trans-cinnamaldehyde) was monitored by UV absorption at 285 nm. The progress of the release of the active ingredient (100 μM) of the prodrug molecule was observed in the presence and absence of β-lactamase. After reacting for 2 hours in the presence of β-lactamase, it was clear that a significant amount of the active ingredient was released. In the absence of β-lactamase, no spontaneous release of the active ingredient was observed.

[0055] Conclusion: The OSTA-1 prodrug molecule functions as expected, is cleavable by β-lactamase, and releases the active ingredient.

[0056] B: Activation of the active ingredient after prodrug disintegration The mode of activation of the active ingredient is shown in Figure 3, which shows the mechanism of the disintegration of the OSTA-1 prodrug and the release of cinnamaldehyde in its active natural form.

Claims

1. A prodrug intended for use in the treatment of infections of bacteria resistant to β-lactam family antibiotics, comprising an antibacterial active ingredient linked to a bait molecule containing a functional group cleavable by β-lactamase, of formula (I): 【Chemical 1】 (wherein, X is either absent or a spacer group selected from a phenylene, alkenylene, or alkynylene group. R １ is a group selected from alkyl, alkylsulfonylethyl, or alkylaminoethyl, for example methyl, dimethyl, methylsulfonylethyl or dimethylaminoethyl, R ２ is a group selected from methyl, 2,2,2-trifluoroethyl, R ３ is a masked antibacterial component, and the masked active ingredient corresponds to a structure of trans-cinnamaldehyde lacking its aldehyde functional group or one of the variants of this structure having retained antibacterial activity. R ４ (which is a β-lactam group derived from cephalosporin, penicillin, or carbapenem) A prodrug characterized by corresponding to.

2. R ４ The prodrug according to claim 1, wherein R is a cephalosporin, penicillin, or carbapenem derivative.

3. The prodrug according to claim 1 or 2, wherein the group X is absent.

4. The prodrug according to any one of claims 1 to 3, selected from OSTA-1 molecule, OSTA-1b molecule, OSTA-5 molecule, OSTA-6 molecule, and OSTA-7 molecule 【Chemical Formula 2】 .

5. A pharmaceutical composition comprising the prodrug according to any one of claims 1 to 4 and at least one acceptable excipient.

6. The prodrug according to any one of claims 1 to 4 for use in the treatment of infections of bacteria resistant to β-lactam antibiotics.

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