EP-4741439-A1 - BLOCK COPOLYMER CONTAINING REPEATING UNIT OF POLY([R, S]BETA-HYDROXYBUTYRATE), NANOPARTICLES FORMED FROM SAID COPOLYMER, AND PRODUCTION AND USE OF THOSE

Abstract

The present description discloses: a (ω-terminal modified) poly(ethylene glycol)-b-poly([R,S]-β-hydroxybutyrate) (PEG-b-PBHB) copolymer, nano-sized polymeric micelles or nanoparticles, which are formed from the copolymer and are capable of controlled release or sustained release of a low molecular weight β-hydroxybutyric acid in vivo; and production or preparation methods of these product, and a pharmaceutical use of the nanoparticles. Since the nanoparticles are capable of controlled release or sustained release of β-hydroxybutyric acid in vivo, physiological activity originally possessed by β-hydroxybutyric acid can be exhibited in vivo.

Inventors

• NAGASAKI, YUKIO
• DUC TRI, Bui

Assignees

• University of Tsukuba

Dates

Publication Date

20260513

Application Date

20240528

Claims (8)

1. A block copolymer represented by Formula I: wherein A represents a hydrogen atom, unsubstituted or substituted C 1 -C 12 alkyl, unsubstituted or substituted C 1 -C 12 alkoxy, or unsubstituted or substituted aryl, a substituent in a case of being substituted represents a C 1 -C 4 alkyl, C 1 -C 4 alkoxy, aryl, formyl, phenylamino, phenethylamino, or a group represented by Formula R 1 R 2 CH- (wherein R 1 and R 2 are independently C 1 -C 4 alkoxy or R 1 and R 2 together represent -OCH 2 CH 2 O-, -O(CH 2 ) 3 O-, or -O(CH 2 ) 4 O-), R represents unsubstituted or substituted C 1-6 alkyl, C 1-4 alkylenecarbonyloxy-unsubstituted or substituted C 1-21 alkyl, C 1-4 alkylenecarbonyloxy-unsubstituted or substituted C 3-7 cycloalkyl, C 1-4 alkylenecarbonyloxy-unsubstituted or substituted aryl, C 1-4 alkylenecarbonyloxy-unsubstituted or substituted adamantyl, C 1-4 alkylene-unsubstituted or substituted aryl, C 1-4 alkylene-unsubstituted or substituted adamantyl, or C 1-4 alkylene-unsubstituted or substituted cholesterol residue, where a substituent in the case of being substituted represents C 1-4 alkyl, C 1-4 alkyloxy, or aryl, m represents an integer of from 20 to 200, n represents an integer of from 3 to 300, p represents an integer of from 1 to 6, and a hydrogen atom of an alkylene with p attached is optionally substituted by one C 1-4 alkyl, and in each β-hydroxylbutyrate unit in a repeating unit with m attached, equivalent amounts of an [R] type enantiomer and an [S] type enantiomer are present randomly from each other.
2. A nano-sized polymeric micelle or nanoparticle comprising the block copolymer according to claim 1.
3. A method for producing a block copolymer represented by Formula I according to Reaction Scheme 1, the production method comprising: preparing a macroinitiator represented by Formula (2) by bringing a dissolved compound represented by Formula (1) into contact with an anionic polymerization catalyst that generates a metal cation represented by M + in an organic solvent that does not adversely affect a reaction; and reacting a [R,S]-β-lactone represented by Formula (3) with a reaction mixture obtained in the preparation, then stopping a polymerization reaction using a halogen substituent represented by Formula (4) and modifying an ω-end of a copolymer to produce a block copolymer represented by Formula I, and obtaining the produced block copolymer: in abbreviations of a variable group or a variable part in each formula in the reaction scheme, A, R, m, n, and p having the same meaning as defined for the copolymer represented by Formula I according to claim 1, and X representing halogen.
4. A method for preparing nano-sized polymeric micelles or nanoparticles of a block copolymer represented by Formula I, the method comprising: forming nano-sized polymeric micelles or nanoparticles by dialysis of a mixture, prepared by adding water dropwise to a solution of the block copolymer represented by Formula I according to claim 1 and dissolved in a water-miscible organic solvent under stirring, against water through a dialysis membrane to prepare an aqueous solution comprising the nanoparticles; and removing an aggregate from the aqueous solution.
5. A pharmaceutical formulation comprising the copolymer represented by Formula I according to claim 1 or the nano-sized polymeric micelle or nanoparticle according to claim 2 as an active ingredient.
6. The pharmaceutical formulation according to claim 5, for use in a treatment of one or more diseases of acute kidney disease, inflammatory disease, brain disease, and cancer.
7. A method for preventing or treating one or more diseases of acute kidney disease, inflammatory disease, and brain disease, the method comprising administering an effective amount of the copolymer represented by Formula I according to claim 1 or the nano-sized polymeric micelle according to claim 2 to a subject or patient in need of treatment.
8. A block copolymer represented by Formula II or an alkali metal salt thereof: wherein A, R, m, n, and p have the same meaning as defined for the copolymer represented by Formula I according to claim 1, R represents a hydrogen atom, and in each β-hydroxylbutyrate unit in a repeating unit with m attached, equivalent amounts of an [R] type enantiomer and an [S] type enantiomer are present randomly from each other.

Description

Technical Field The present invention relates to a block copolymer comprising a repeating unit of poly([R,S]β-hydroxybutyrate), and more particularly, to a poly(ethylene glycol)-b-poly([R,S]β-hydroxybutyrate) (PEG-b-PBHB) copolymer, and a production method and use thereof. Background Art Since β-hydroxybutyric acid (BHB) which is one of body ketone bodies is involved in various signal transduction pathways (for example, energy metabolism, inflammatory response), its supplements provide benefits for treatment of many diseases. For example, Tajima T. et. al., Kidney international, 2019, 95 (5), 1120-1137 (hereinafter, it may be referred to as Non-Patent Document 1) report that injection of BHB reduces renal ischemia reperfusion injury if it has an effect on continuous delivery of BHB. However, BHB is a low molecular weight compound that is easily eliminated from the body after administration. Thus, it would be more advantageous to utilize physiological activity of BHB in therapeutic applications if it is possible to provide a controlled release (or sustained release) formulation of BHB. One of strategies related to a current controlled release formulation is to produce an amphiphilic copolymer by PEGylation and then prepare nanoparticles from the copolymer for the purpose of increasing a molecular weight of a low molecular weight compound capable of releasing the low molecular weight compound via disintegration of nanoparticles and the amphiphilic copolymer. For example, WO 2020/166473 (hereinafter, it may be referred to as Patent Document 1) discloses that controlled-release nanoparticles (NanoL-DOPA) of L-DOPA prepared from poly(ethylene glycol)-b-poly(L-DOPA) exhibit an advantageous therapeutic effect and reduce a detrimental effect by improving a pharmacokinetic profile of L-DOPA. Indeed, a number of known research papers report on synthesis of diblock copolymers of poly(ethylene glycol) (PEG) and poly(β-hydroxybutyrate) (PBHB) with attempts at nanoparticle preparation (see, for example, Jeong, K. H. et. al., Macromolecular Research, 2008, 16, 418 - 423, Ravenelle, F. et. al., Biomacromolecules, 2003, 4 (3), 856 - 858). In these studies, a diblock copolymer is synthesized by an esterification reaction between a PEG derivative and a natural poly([R]-β-hydroxybutyrate) hydrolysis product derived from commercially available bacteria and having a high molecular weight (MW 200,000 to 1,000,000 g/mol). Thus, flexibility for controlling the number of BHB units contained in the copolymer becomes poor. In addition, poly([R]-β-hydroxybutyrate) exhibits a high crystallization tendency and forms crystals rapidly, thus making self-assembly that occurs naturally in water difficult and requiring strict conditions for preparation of nanoparticles (CA 2430442 A1, hereinafter, may be referred to as Patent Document 2). For example, Patent Document 2 proposes preparation of nanoparticles by a time-consuming evaporation method from a copolymer as described above, in which a block copolymer is continuously stirred for a long time (that is, two weeks) in the form of an O/W emulsion to slowly evaporate an organic phase, thereby preparing target nanoparticles. Therefore, if a means capable of sustained release or controlled release of β-hydroxybutyrate having an intended physiological activity can be obtained without the above-described problems or difficulties in the prior art, it would contribute to the progress of the art. Summary of Invention Technical Problem From a pharmacological point of view, a small molecule BHB drug (sodium β-hydroxybutyrate) exhibits a very short half-life in vivo after administration (in particular, in an injection path), and therefore, its physiological activity is reduced. Therefore, an object of the present invention is to provide a means including a formulation capable of sustained release or controlled release of BHB having the physiological activity involved in various signal transduction pathways and the like. From the viewpoint of material design, poly(β-hydroxybutyrate) (hereinafter, it may be referred to as "PBHB") is a hydrophobic polyester, and is not suitable for drug administration by an injection path because poly(β-hydroxybutyrate) causes aggregation in an aqueous environment. Accordingly, it is a further object of the present invention to provide a material that can be stably prepared in an aqueous environment and can be stably present. Solution to Problem To the best of the present inventor's knowledge, it is undocumented that chemically synthesized PBHB, unlike natural or microorganism-derived or plant-derived poly([R]-β-hydroxybutyrate), exhibits the same physiological activity as natural BHB intended for pharmaceutical applications and the like. On the other hand, since one carboxyl group and one hydroxyl group are simultaneously present in the structure of BHB, BHB can be bonded to each other via an ester bond to form a polymer. Actually, BHB in a polymerized form, that is, poly