Multi-arm star polymer with hyperbranched polyalkyleneimine core and long alkyl side chains

Abstract

The present invention provides a multi-arm star polymer that comprises a branched polyalkyleneimine core, an intermediate region of repeating branching units of short hydrocarbon units containing amide and terminal amine functional groups and a large number of linear long hydrocarbon chain segments. The synthesis of the molecule involves fewer steps and takes less time when compared with the synthesis of equivalent dendrimers. This molecule can be used as a drug carrier for a wide variety of hydrophobic and partially hydrophobic drugs, oils such as essential and ayurvedic oils and fragrance carrier and as a demulsifier for separating water from water in crude oil emulsions.

Description

[0001] MULTI- ARM STAR POLYMER WITH HYPERBRANCHED POLYALKYLENEIMINE CORE AND LONG ALKYL SIDE CHAINS

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to multi-arm hyperbranched star polymer having number of generations and a method of synthesisthereof.

[0004] BACKGROUND OF THE INVENTION

[0005] Hyperbranched polymers are highly branched structures with a multiplicity of reactive chain endsand all of their bonds converge to a focal point or core. Unlike dendrimers, they do not have awell-defined structure. This architecture has the advantage over dendrimers of synthesizing highlybranched polymer with fewer steps and within less time. Due to their unique physical and chemicalproperties and potential applications in various fields, researchers are interested to synthesize hyperbranched polymers with various architectures.

[0006] US6140276 discloses a novel N-substituted polyalkyleneimine compound that reduces the deposition of wax incrude oil. The novel N-substituted polyalkyleneimine compound has at least one organic substituent of the alkyl group of 12-24carbon atoms such as octyl, dodecyl, hexadecyl or palmityl, octadecyl or stearyl. The organic substituent can also be an aryl group or cycloalkyl group. The aryl group contains 6-30 carbon atoms, while the cycloalkyl group contains 5-10 carbon atoms. The organic substituent can be bonded directly or via an intermediate group usually a polar group. The backbone of the compound can be linear or branched with branching on each 1-10 nitrogenatoms. The organic substituent can be attached directly or through an intermediate polar group with the nitrogen atom of the backbone of the compound.

[0007] EP680498 discloses small cell foams and blends and a process for their preparation. In this work, the inventors have prepared dense star polymers or dendrimers modified bycapping with a hydrophobic group which produces a hydrophobic outer shell of themolecule. This molecule has a highly branched interior of one monomeric compositionand an exterior structure of a different monomeric composition. The interior structure ofthe molecule is comprised of an amine-terminated polyamidoamine dendrimer, a hydroxy-terminated polyether dendrimer, an amine-terminated polyethyleneimine or an amine-terminated polypropyleneimine dendrimer. The hydrophobic outer shell of the moleculeis comprised of hydrophobic groups of 4-40 carbon atoms. The particle size is 5 to 300 nm. The dense star polymer is a 5 to 10-generationamine-terminated polyamidoamine dendrimer modified with 4,4-diphenylbut-l-eneoxideorl l,l l- diphenylundec-l-ene oxide.

[0008] CA1275539C discloses a rod-shaped dendrimer having a plurality of dendritic branches emanating from an essentially linear core. This dendrimer is prepared by first reacting a linear polyfunctional core compound such as a polyethyleneimine with an ester of an unsaturated carboxylic acid, e.g., methyl acrylate and then successively reacting with ethylenediamine. The co-reactants for the reaction with the electrophilic core include polyalkylene polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine and other polyamines.

[0009] US5527524 discloses dense star polymer conjugates. The dense star polymer conjugates are composed of at least one dendrimer in association with at least one unit of a carrier material. The dense star polymer is a radially symmetrical dendrimer. The dendrimer portion of the conjugates can be polyamidoamine or polyethyleneimine. The dendrimer is a third-generation dendrimer. The dense star polyethyleneimine has a methylene carboxylate or acetate surface or a surface of a polyamidoamine. The surface of the dendrimer can also be modified with a functional group.

[0010] Rainer Haag et al in ChemBioChem (2004) reported dendritic polyamines assimple access to new materials with defined tree-like structures for application in non-viral gene delivery. Synthesis of dendritic polyamines with different molecular weights andadjustable flexibility (degrees of branching; DB) influences the transfection efficiency and the cell toxicity of the polymer. Functionalization of hyperbranched polyethylenimine (PEI) by a two-step procedure is generated by fully branched pseudodendrimers (analogues of polypropylenimine (PPI) and polyamidoamine (PAMAM) dendrimers). Such dendrimers are used for DNA transfection. The cytotoxicity of the dendrimers generally rises with increasing core size.

[0011] Ulrich S. Schubert et al reported branched and linear poly (ethyleneimine) -based conjugates: synthetic modification, characterization, and application. The high ability of cationic PEIs to complex and condense negatively charged DNA and RNA combined with their inherent proton sponge behavior accounts for excellent efficiencyin gene delivery. Further chemical modifications of the polymer expand the application potential, primarily aiming at increased transfection efficiency, cell selectivity and reduced cytotoxicity.

[0012] Polyalkyleneimine dendrimers and molecules can be tailored to develop novel polymers for specific end uses and wide-ranging applications in the field of chemicals and pharmaceuticals. The strength and utility of a polymer largely depend on its chain length and number of branches. The more the chain length, the more the number of branches of a polymer, and difficult it is to pull it apart. Thus, accommodating a very large number of long terminal alkyl side chain segments on the surface of a branched polyalkyleneimine molecule is desirable but challenging due to steric hinderance caused between the long terminal alkyl side chains. Accordingly, there is a need to provide a novel strong branched polyalkyleneimine polymer having a higher number of long terminal alkyl side chain sand the method for preparation thereof. OBJECT OF THE INVENTION

[0013] It is an object of the present invention to provide a novel multi-arm star polymer having a large number of long terminal alkyl side chains and the method of preparation thereof.

[0014] It is further an object of the present invention to provide a method of preparation of a multi-arm star polymer having multiple generations.

[0015] It is yet another object of the present invention to provide a multi-arm star polymer with hyperbranched polyalkyleneimine core and long alkyl side chains of acrylic esters.

[0016] It is yet another object of the present invention to provide a novel multi-arm star polymer with hyperbranched polyalkyleneimine core and long alkyl side chains of acrylic esters that can have applications, particularly in the field of petroleum, pharmaceuticals and consumer goods.

[0017] BRIEF DESCRIPTION OF THE FIGURES

[0018] Figure 1 illustrates synthesis scheme of multi-arm star polymer with hyperbranched poly alkyleneimine core and long alkyl side chains.

[0019] Figure 2 illustrates FTIR data of multi-arm star polymer with hyperbranched polyethyleneimine core and long alkyl side chains.

[0020] Figure 3 illustrates (a)1H NMR data and (b) Sketch of multi-arm star polymer with hyperbranchedpoly ethyleneimine core and long alkyl side chains.

[0021] SUMMARY OF THE INVENTION

[0022] In an aspect of the present invention there is provided a multi-arm star polymer of Formula (A),

[0023] characterized in having

[0024] (i) a branched polyalkyleneimine core (C) of molecular weight ranging from about 400 g / mol to about 160,000 g / mol, with 15-50% ‘p’, 20-60% ‘s’ and 20- 45% ‘t’ amine groups,

[0025] (ii) a plurality of short intermediate hydrocarbon units (Sh) containing amide and terminal amine functional group attached to ‘p’ or ‘p’ and ‘s’ amine groups of the polyalkyleneimine core (C);

[0026] (iii) a plurality of long alkyl side-chains (Lh) are attached to the terminal amine functional group of the short intermediate hydrocarbon units (Sh), wherein, the plurality of short intermediate hydrocarbon units (Sh) is denoted by 2g-1(2p + s), and the plurality of long alkyl side-chain (Lh) is denoted by 2g(2p + s);

[0027] ‘p’ is the number of terminal primary amine group (-NH2), and ‘s’ is the number of secondary amine group and ‘t’ is the number of tertiary amine group in the branched polyalkyleneimine core (C);

[0028] ‘g’ is generation of the multi-arm star polymer, and ‘g’ = 1, 2, 3... and p>6, s>3, and wherein when ‘g’ is greater than 1, the plurality of short intermediate hydrocarbon units (Sh) attached to the core (C) is further attached a plurality of short intermediate hydrocarbon units (Sh). In another aspect of the present invention there is provided a first-generation multi-arm star polymer having a structure of formula I, wherein R is an alkyl chain with carbon number C1-C4, is an alkyl chain with carbon number C2-C5, R2 is an alkyl group with carbon numbers Cs to C34, and “n” is an integer between 1 and 200, preferably between 1 and 60.

[0029] In another aspect of the invention there is provided a second-generation multi-arm star polymer having the structure of formula II, wherein, R is an alkyl chain with carbon numbers C1-C4, ^4 is an alkyl chain with carbon numbers C2-C5, R2 is long hydrocarbon chain with carbon numbers C8-C34, and “n” is an integer between 1 and 200, preferably between 1 and 60.

[0030] In another aspect of the invention there is provided a method for preparation of the multi-arm star polymer of formula (A) which comprises the steps of: i. attaching a plurality of short intermediate hydrocarbon units (Sh) to a branched polyalkyleneimine core (C) having ‘p’ and ‘s’ amine groups, comprising of following two sub steps of reaction:

[0031] (a) reacting a branched polyalkyleneimine having core (C) having ‘p’ and ‘s’ amine groups with alkyl acrylate in a solvent at 25-50°C to produce ester- terminated hyperbranched polyalkyleneimine having a plurality of ester groups, attached to ‘p’ or ‘p’ and ‘s’ amine groups of the polyalkyleneimine core (C), (b) adding alkylene diamine to said ester-terminated hyperbranched polyalkyleneimine having a plurality of ester groups, attached to p and s amine groups of the polyalkyleneimine core (C) of step (ia) in a solvent at 25-50°C to produce a first generation of an amino-terminated hyperbranched polyalkyleneimine having plurality of short intermediate hydrocarbon chains (Sh) attached to ‘p’ or ‘p’ and s amine groups of the polyalkyleneimine core (C), ii. optionally, repeating reaction step (ia) and (ib) to first attach alkyl acrylate to said first generation amino-terminated hyperbranched polyalkyleneimine of step (ib) in a solvent at 25-50°C followed by attaching alkylene diamine in a solvent at 25-50°C to produce amino-terminated hyperbranched polyalkyleneimine having plurality of short intermediate hydrocarbon unit (Sh), attached to ‘p’ or ‘p’ and ‘s’ amine groups of the polyalkyleneimine core (C), and to plurality of short intermediate hydrocarbon units (Sh), iii. adding long chain alkyl acrylate to said amino-terminated hyperbranched polyalkyleneimine having plurality of short intermediate hydrocarbon chains (Sh) of step (i) or step (ii) in a solvent at 25-50°C to obtain two long alkyl side-chains (Lh) linked with each terminal N of an amino-terminated short intermediate hydrocarbon chain (Sh), wherein said plurality of short intermediate hydrocarbon chain (Sh) is denoted by 2g-1(2p + s), and the plurality of long alkyl side-chain (Lh) is denoted by 2g(2p + s); wherein ‘p’ is the number of terminal primary amine group (-NH2), and ‘s’ is the number of secondary amine group in the branched poly alkyleneimine core (C); wherein the optionally step (ii) can be repeated multiple times, wherein p>6, s>3 and g = 1, 2, 3. . . .

[0032] In another aspect of the invention there is provided a pharmaceutical composition comprising the multi-arm star polymer of formula (A) and an active pharmaceutical ingredient, where the active pharmaceutical ingredient is hydrophobic in nature. In another aspect of the invention there is provided an oil and fragrance carrier comprising the multi-arm polymer of formula (A).

[0033] In another aspect of the invention there is provided a demulsifier comprising the multi- arm polymer of formula (A).

[0034] In another aspect of the invention there is provided a multi-arm star polymer comprising polyethyleneimine core, having a formula III, wherein R2 is long hydrocarbon chain with carbon numbers C8-C34.

[0035] In another aspect of the invention there is provided a multi-arm star polymer comprising polypropyleneimine core, having a formula IV,

[0036] wherein R2 is long hydrocarbon chain with carbon numbers C8-C34.

[0037] In another aspect of the invention there is provided a multi-arm star polymer comprising polybutyleneimine core, having a formula V, wherein R2 is long hydrocarbon chain with carbon numbers C8-C34. DETAILED DESCRIPTION OF THE INVENTION

[0038] The following detailed description of the invention is provided to aid those skilled in the art in practicing the present invention. Even so, the detailed description should not be construed to unduly limit the present invention as modifications and verifications in the embodiments discussed herein may be made by those of skill in the art with the help of the foregoing description and accompanying figures without departing from the spirit or scope of the present inventive discovery.

[0039] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skilled in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

[0040] It is to be understood that the singularforms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0041] The terminology used herein is for the purpose of describing particular various embodiments only and is not intended to be limiting to various embodiments. It will be further understood that the terms "comprises" and / or "comprising" used herein specify the presence of stated features, integers, steps, operations, members, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, members, components, and / or groups thereof. Also, expressions such as "at least one of," when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

[0042] Described herein is a multi-arm star polymer having multiple generations with a long terminal alkyl side chains and the method for preparation thereof.

[0043] In an embodiment, there is provided a multi-arm star polymer of Formula (A),

[0044] A

[0045] The multi-arm star polymer of formula A is characterized with a branched polyalkyleneimine core (C), having ‘p’, ‘s’, and ‘t’ amine groups.

[0046] The designation ‘p’ denotes the number of terminal primary amine group, designation ‘s’ denotes the number of secondary amine group and designation ‘t’ denotes the number of tertiary amine group in the branched polyalkyleneimine core (C). where, R is alkyl chain with carbon numbers C1-C4 and “n” is an integer between 1 and 200, preferably between 1 and 60.

[0047] The multi-arm star polymer of Formula (A) is further characterized with a plurality of short intermediate hydrocarbon units (Sh) containing amide and terminal amine functional group.

[0048] Sh

[0049] The plurality of short intermediate hydrocarbon units (Sh) in the multi-arm star polymer of Formula (A) are attached to primary amines ‘p’ or to both primary amines ‘p’ and secondary amine ‘s’ of the polyalkyleneimine core (C), as -Cn-Sh-

[0050] , where each ‘p’ is attached to two short intermediate hydrocarbon units (Sh).

[0051] -Cn-Sh- where R = an alkyl chain with carbon number C2-C5.

[0052] The compound-Cn-Sh- as shown above has polyalkyleneimine core (C), outlined with green color and short intermediate hydrocarbon units(Sh), attached to the core (C), outlined with red color. The short intermediate hydrocarbon units(Sh), attached to the core (C) have terminal amine functional group, for further attachments. In an embodiment, the multi-arm star polymer of Formula (A) having polyalkyleneimine core (C) with ‘p’ and ‘s’ amine groups attached to plurality of short intermediate hydrocarbon units (Sh) having terminal amine groups is characterized with a plurality of long alkyl side-chains (Lh), as -Cn-Sh-Lh,

[0053]

[0054] Sh-Lh where a plurality of long alkyl side chains (Lh) are attached to the terminal amine of the short intermediate hydrocarbon unit (Sh), such that each terminal amine of the core (C) is attached to two short intermediate hydrocarbon unit (Sh), and each terminal amine of Sh is attached to two long alkyl side-chains (Lh), where Lh is , and where R2 = C8-C34.

[0055] The compound-Cn-Sh-Lh as shown above has poly alkyleneimine core (C), outlined with green colour; short intermediate hydrocarbon units(Sh), attached to the core (C), outlined with red colour; and Lh present beyond the red boundary. The long terminal alkyl side chain (Lh) comprises an acrylic ester functionality selected from the group of octyl, lauryl, palmityl, stearyl, behenyl, lignoceryl, ceryl acrylate, aryl acrylate or heteroaryl acrylates, etc. In an embodiment, the multi-arm star polymer of Formula (A) having polyalkyleneimine core (C) with ‘p’ and ‘s’ amine groups attached to plurality of short intermediate hydrocarbon units (Sh) having terminal amine groups and a plurality of long alkyl side-chains (Lh), attached to plurality of short intermediate hydrocarbon units (Sh), is characterized with further attachments of plurality of short intermediate hydrocarbon units (Sh), where each short intermediate hydrocarbon units (Sh) having terminal amine group is attached to a plurality of short intermediate hydrocarbon units (Sh), as -C-Sh-Sh-Lh.

[0056] The compound-Cn-Sh-Sh-Lh as shown above has polyalkyleneimine core (C), outlined with green colour; plurality of short intermediate hydrocarbon units (Sh), attached to plurality of short intermediate hydrocarbon units (Sh), outlined with two red color boundaries; and Lh present outside the red boundary.

[0057] In an embodiment, the multi-arm star polymer of Formula (A), where a plurality of short intermediate hydrocarbon units (Sh) having terminal amine groups attaches to a plurality of short intermediate hydrocarbon units (Sh), as -Cn-Sh-Sh- Sh-....-Sh-Lh.

[0058] In an embodiment of the present invention there is provided a multi-arm star polymer of Formula (A), having generations, ‘g’, where ‘g’ = 1,2, 3, 4.

[0059] In an embodiment of the present invention there is provided a multi-arm star polymer having ‘g’ = 1, with a Formula (I),

[0060] The multi-arm star polymer of formula (I) is characterized with

[0061] (i) a polyalkyleneimine core (C) with ‘p’ and ‘s’ amine groups,

[0062] (ii) a plurality of short intermediate hydrocarbon units (Sh) containing amide and terminal amine functional group attached to ‘p’ or ‘p’ and ‘s’ of the polyalkyleneimine core (C)^and (iii) a plurality of long alkyl side-chains (Lh) attached to the terminal amine functional group of the short intermediate hydrocarbon units (Sh), where the plurality of short intermediate hydrocarbon units (Sh) attached to ‘p’ or

[0063] ‘p’ and ‘s’ of the polyalkyleneimine core (C) and plurality of long alkyl side- chains (Lh), where R is an alkyl chain with carbon number C1-C4, Ri is an alkyl chain with carbon number C2-C5, R2 is an alkyl group with carbon numbers Cs to C34, and “n” is an integer between 1 and 200, preferably between 1 and 60. In an embodiment of the present invention there is provided a multi-arm star polymer having ‘g’ = 2, with a Formula (II), The multi-arm star polymer of Formula (II), is characterized with

[0064] (i) a polyalkyleneimine core (C) with ‘p’ and ‘s’ amine groups, (ii) a plurality of short intermediate hydrocarbon units (Sh) containing amide and terminal amine functional group attached to ‘p’ or ‘p’ and ‘s’ of the polyalkyleneimine core (C) ind

[0065] (iii) a plurality of long alkyl side-chains (Lh) attached to the terminal amine functional group of the short intermediate hydrocarbon units (Sh), where the plurality of short intermediate hydrocarbon units (Sh)is attached to plurality of short intermediate hydrocarbon units (Sh). where, R is an alkyl chain with carbon numbers C1-C4, Ri is an alkyl chain with carbon numbers C2-C5, R2 is long hydrocarbon chain with carbon numbers C8-C34, and “n” is an integer between 1 and 200, preferably between 1 and 60.

[0066] In an embodiment, the multi- arm star polymer of Formula (A) is characterized with a branched polyalkyleneimine core (C), having a molecular weight in the range from 400-160,000 g / mol.

[0067] The branched poly alkyleneimine core (C), having molecular weight in the range from 400-160,000 g / mol, is characterized with 15-50% of ‘p’, 20-60% of ‘s’ and 20-45% of ‘t’ amine groups.

[0068] The multi-arm star polymer of Formula (A) is characterized with plurality of short intermediate hydrocarbon units (Sh) having a molecular weight equal to or greater than 115g / mol.

[0069] The multi-arm star polymer of Formula (A) is characterized with plurality of long alkyl side chain (Lh) having a molecular weight greater than 180 g / mol.

[0070] In an embodiment, the multi-arm star polymer of Formula (A) is characterized with a branched polyalkyleneimine core (C), having ‘ 15-50% ‘p’, 20-60% ‘s’ amine groups, and where ‘p’> 6 and ‘s’ >3. The present invention therefore provides a multi-arm star polymer of Formula (A), characterized in having

[0071] (i) a branched polyalkyleneimine core (C) of molecular weight ranging from about 400 g / mol to about 160,000 g / mol, with 15-50% ‘p’, 20-60% ‘s’ and 20- 45% ‘t’ amine groups,

[0072] (ii) a plurality of short intermediate hydrocarbon units (Sh) containing amide and terminal amine functional group attached to ‘p’ or ‘p’ and ‘s’ amine groups of the poly alkyleneimine core (C);

[0073] (iii) a plurality of long alkyl side-chains (Lh) are attached to the terminal amine functional group of the short intermediate hydrocarbon units (Sh), wherein, the plurality of short intermediate hydrocarbon units (Sh) is denoted by 2g-1(2p + s), and the plurality of long alkyl side-chain (Lh) is denoted by 2g(2p + s);

[0074] ‘p’ is the number of terminal primary amine group (-NH2), and ‘s’ is the number of secondary amine group and ‘t’ is the number of tertiary amine group in the branched poly alkyleneimine core (C);

[0075] ‘p’ >6, ‘s’ >3

[0076] ‘g’ denotes generation of the multi-arm star polymer, and ‘g’ = 1, 2, 3. . . , wherein when ‘g’ is greater than 1, the plurality of short intermediate hydrocarbon units (Sh) attached to the core (C) is further attached a plurality of short intermediate hydrocarbon units (Sh).

[0077] In a preferred embodiment, there is provided first generation multi-arm star polymers having structures of formula III, formula IV and formula V as represented below:

[0078]

[0079] IV

[0080] 5

[0081] where R2 is long terminal alkyl side chain with carbon numbers C8-C34. The first generation multi-arm star polymer having structure of formula III contains a branched polyethyleneimine core and long chain acrylic esters, wherein the long chain acrylic esters are attached to the branched polyethyleneimine core via the short intermediate hydrocarbon units (Sh) containing both amide and amine groups, with amine as terminal group.

[0082] The first generation multi-arm star polymer having structure of formula IV contains a branched polypropyleneimine core and long chain acrylic esters, wherein the long chain acrylic esters are attached to the branched polypropyleneimine core via the short intermediate hydrocarbon units (Sh) containing both amide and amine groups, with amine as terminal group.

[0083] The first generation multi- arm star polymer having structure of formula V contains a branched polybutyleneimine core and long chain acrylic esters, wherein the long chain acrylic esters are attached to the branched polybutyleneimine core via the short intermediate hydrocarbon units (Sh) containing both amide and amine groups, with amine as terminal group.

[0084] The backbone of the first generation multi-arm star polymers in the above compounds having formula III, IV and V are branched polyalkyleneimine having high molecular weight, greater than 400 g / mol and less than 160,000 g / mol.

[0085] Preferably, the molecular weight of the core of the first generation multi-arm star polymer having the structure of formula III is 800 g / mol (branched polyethyleneimine), while for formula IVand formula V are 968 g / mol (branched polypropyleneimine) and 1136 g / mol (branched polybutyleneimine) respectively.

[0086] In another embodiment, there is provided a method for the preparation of the multi-arm star polymer of formula (A) having ‘g’ generations, comprising polyalkyleneimine core, a plurality of short intermediate hydrocarbon units (Sh) and plurality of long terminal alkyl side chain.

[0087] The method for preparation of multi-arm star polymer of formula (A) having ‘g’ generations, is based on Michael addition reaction and comprises the following steps: i. attaching a plurality of short intermediate hydrocarbon units (Sh) to a branched polyalkyleneimine core (C) having ‘p’ and ‘s’ amine groups, comprising of following two sub steps of reaction:

[0088] (a) reacting a branched polyalkyleneimine core (C) having ‘p’ and ‘s’ amine groups with alkyl acrylate in a solvent at 25-50°C to produce ester-terminated hyperbranched polyalkyleneimine having a plurality of ester groups, attached to ‘p’ or ‘p’ and ‘s’ amine groups of the polyalkyleneimine core (C),

[0089] (b) adding alkylene diamine to said ester-terminated hyperbranched polyalkyleneimine having a plurality of ester groups, attached to p and s amine groups of the polyalkyleneimine core (C) of step (ia) in a solvent at 25-50°C to produce a first generation of an amino-terminated hyperbranched polyalkyleneimine having plurality of short intermediate hydrocarbon chains (Sh) attached to ‘p’ or ‘p’ and ‘s’ amine groups of the polyalkyleneimine core (C)7ii. optionally, repeating reaction step (ia) and (ib) to first attach alkyl acrylate to said first generation amino-terminated hyperbranched polyalkyleneimine of step (ib) in a solvent at 25-50°C followed by attaching alkylene diamine in a solvent at 25-50°C to produce amino-terminated hyperbranched polyalkyleneimine having plurality of short intermediate hydrocarbon unit (Sh), attached to ‘p’ or ‘p’ and ‘s’ amine groups of the polyalkyleneimine core (C), and to plurality of short intermediate hydrocarbon units (Sh), iii. adding long chain alkyl acrylate to said amino-terminated hyperbranched polyalkyleneimine having plurality of short intermediate hydrocarbon chains (Sh) of step (i) or step (ii) in a solvent at 25-50°C to obtain two long alkyl side-chains (Lh) linked with each terminal N of an amino-terminated short intermediate hydrocarbon chain (Sh), wherein plurality of short intermediate hydrocarbon chain (Sh) is denoted by 2g-1(2p + s), and the plurality of long alkyl side-chain (Lh) is denoted by 2g(2p + s); wherein ‘p’ is the number of terminal primary amine group (-NH2), and ‘s’ is the number of secondary amine group in the branched poly alkyleneimine core (C); wherein the optionally step (ii) can be repeated multiple times, wherein p>6, s>3, and g = 1, 2, 3. . . .

[0090] The solvent as used in the method steps (i), (ii), and (iii) for preparation of the multi-arm star polymer of the formula (A) is selected from methanol, toluene, chloroform, tetrahydrofuran.

[0091] The method steps for the preparation of the multi-arm star polymer of the formula (A) is carried out in varied reaction time, as the reaction time of the method depends on the molecular weight of the branched polyalkyleneimine core (C) in the polymer, which can vary from 400 g / mol to 160,000 g / mol. The method step (ia) for the preparation of the multi-arm star polymer of the formula (A) is carried out for a duration of 36-96 hrs. The method step (ib) for the preparation of the multi-arm star polymer of the formula (A) is carried out for a duration of 48-120 hrs. The method step (iii) for the preparation of the multi-arm star polymer of the formula (A) is carried out for a duration of 36-96 hrs.

[0092] The method for preparation of multi-arm star polymer of formula (I) having ‘g’ = 1 comprises the following steps: i. attaching a plurality of short intermediate hydrocarbon units (Sh) to a branched polyalkyleneimine core (C) having ‘p’ and ‘s’ amine groups, comprising of following two sub steps of reaction:

[0093] (a) reacting a branched polyalkyleneimine core (C) having ‘p’ and ‘s’ amine groups with alkyl acrylate in a solvent at 25-50°C to produce ester-terminated hyperbranched polyalkyleneimine having a plurality of ester groups, attached to ‘p’ or ‘p’ and ‘s’ amine groups of the polyalkyleneimine core (C),

[0094] (b) adding alkylene diamine to said ester-terminated hyperbranched polyalkyleneimine having a plurality of ester groups, attached to p and s amine groups of the polyalkyleneimine core (C) of step (ia) in a solvent at 25-50°C to produce a first generation of an amino-terminated hyperbranched polyalkyleneimine having plurality of short intermediate hydrocarbon chains (Sh) attached to ‘p’ or ‘p’ and ‘s’ amine groups of the polyalkyleneimine core (C)7iii. adding long chain alkyl acrylate to said amino-terminated hyperbranched polyalkyleneimine having plurality of short intermediate hydrocarbon chains (Sh) of step (i) or step (ii) in a solvent at 25-50°C to obtain two long alkyl side-chains (Lh) linked with each terminal N of an amino-terminated short intermediate hydrocarbon chain (Sh), wherein the plurality of short intermediate hydrocarbon chain (Sh) is denoted by 2g-1(2p + s), and the plurality of long alkyl side-chain (Lh) is denoted by 2g(2p + s); wherein ‘p’ is the number of terminal primary amine group (-NH2), and ‘s’ is the number of secondary amine group in the branched poly alkyleneimine core (C); wherein theoptionally step (ii) can be repeatedmultiple times, wherein p>6, s>3.

[0095] The method for preparation of multi-arm star polymer of formula (II) having ‘g’ = 2, which comprises the following steps: i. attaching a plurality of short intermediate hydrocarbon units (Sh) to a branched polyalkyleneimine core (C) having ‘p’ and ‘s’ amine groups, comprising of following two sub steps of reaction:

[0096] (a) reacting a branched polyalkyleneimine core (C) having ‘p’ and ‘s’ amine groups with alkyl acrylate in a solvent at 25-50°C to produce ester-terminated hyperbranched polyalkyleneimine having a plurality of ester groups, attached to ‘p’ or ‘p’ and ‘s’ amine groups of the polyalkyleneimine core (C),

[0097] (b) adding alkylene diamine to said ester-terminated hyperbranchedpolyalkyleneimine having a plurality of ester groups, attached to p and s amine groups of the polyalkyleneimine core (C) of step (ia) in a solvent at 25-50°C to produce a first generation of an amino-terminated hyperbranched polyalkyleneimine having plurality of short intermediate hydrocarbon chains (Sh) attached to ‘p’ or ‘p’ and ‘s’ amine groups of the polyalkyleneimine core (C)7ii. repeating reaction steps (ia) and (ib) one time to first attach alkyl acrylate to said first generation amino-terminated hyperbranched polyalkyleneimine of step (ib) in a solvent at 25-50°C followed by attaching alkylene diamine in a solvent at 25-50°C to produce amino-terminated hyperbranched polyalkyleneimine having plurality of short intermediate hydrocarbon unit (Sh), attached to ‘p’ or ‘p’ and ‘s’ amine groups of the polyalkyleneimine core (C), and to plurality of short intermediate hydrocarbon units (Sh), iii. adding long chain alkyl acrylate to said amino-terminated hyperbranched polyalkyleneimine having plurality of short intermediate hydrocarbon chains (Sh) of step (i) or step (ii) in a solvent at 25-50°C to obtain two long alkyl side-chains (Lh) linked with each terminal N of an amino-terminated short intermediate hydrocarbon chain (Sh), wherein plurality of short intermediate hydrocarbon chain (Sh) is denoted by 2g-1(2p + s), and the plurality of long alkyl side-chain (Lh) is denoted by 2g(2p + s); wherein ‘p’ is the number of terminal primary amine group (-NH2), and ‘s’ is the number of secondary amine group in the branched poly alkyleneimine core (C); wherein p>6, s>3.

[0098] The multi-arm star polymer of the formula (A) having ‘g’ = 1, 2, 3 and 4 generations of the polymer can be prepared by the above method without causing any steric effect, where the multi-arm star polymer is characterized with a scattered web like morphology.

[0099] The multi-arm star polymer with hyperbranched polyalkyleneimine core and long alkyl side chains so formed isused in various fields.

[0100] In an embodiment there is provided a pharmaceutical composition comprising an active ingredient and a multi-arm star polymer.

[0101] The multi-arm star polymer with hyperbranched polyalkyleneimine core and long alkyl side chains can be used as a drug carrier for a wide variety of hydrophobic and partially hydrophobic drugs such as curcumin, ibuprofen, paracetamol, acetaminophen, vitamin B12.

[0102] These drugs can be physically encapsulated into the cavities of multi-arm star polymer via hydrophobic interaction and hydrogen bonding. As the multi-arm star polymer has a larger number of branches of longer carbon chain segments and various polar groups such as -NH, -CO and -COO, more drug molecules can be loaded into the cavities of this polymer due to the hydrogen bonding of drug molecule with amine, amide and ester groups and due to hydrophobic interaction between carbon chain segments and aromatic rings of a drug molecule with long carbon chains of the polymer. As a result, smaller dosages of this polymer will be efficient in carrying and releasing a sufficient number of drugs at the targeted site.

[0103] In an embodiment there is provided an essential oil carrier comprising the first generation multi-arm polymer having the structure of formula III.

[0104] The multi-arm star polymer with hyperbranched polyalkyleneimine core and long alkyl side chains can be used as an ayurvedic oil carrier for certain ayurvedic oils such as clove oil, castor oil, neem oil and lavender oil. These ayurvedic oils can be loaded inside the cavities of the multi-arm star polymer due to the hydrogen bonding between the polar groups of ayurvedic oil with -NH, -CO and -COO groups of the polymer and hydrophobic interaction between long carbon chain of the polymer with the aromatic and aliphatic long carbon chain of the ayurvedic oils.

[0105] The multi-arm star polymer with hyperbranched polyalkyleneimine core and long alkyl side chains can be used as a fragrance carrier for various aroma essential oils, agrumen and aliphatic aldehydes. Polar groups of terpenoid and phenylpropanoid derivatives present in aroma essential oils can form a hydrogen bond with the -NH, -CO and -COO groups of the polymer. Moreover, aliphatic long carbon chains of the aroma essential oils can attach with the long carbon chains of the multi-arm star polymer due to the hydrophobic interaction between them. As a result, fragrance-containing aroma essential oils, agrumen and aliphatic aldehydes can be loaded inside the cavities of the multi-arm star polymer. A little amount of polymer can load and carry a significant amount of fragrance molecules. The various applications and preparations of the muti-arm star polymers have been illustrated by way of non-limiting examples. Example 1: Preparation of Multi-arm polymer having Polyethyleneimine(PEI) core

[0106] Branched polyethyleneimine(PEI) of molecular weight 800 Da is used in this synthesis step. 0.01 mol of PEI (800 Da) was dissolved in 70 ml of methanol and the solution was cooled in an ice bath. 21.9 g (0.0254 mol) of methyl acrylate (MA) was added dropwise into a three-necked round-bottomed (RB) flask containing PEI solution equipped with a magnetic stirrer, a reflux condenser, and a heater. The reaction temperature was then raised to 50°C and allowed to react for 48 hours. A slight excess of MA was used in this reaction to obtain the ester- terminated hyperbranched PEI. The excess MA and methanol were removed by rotary evaporation at 40°C resulting in amber-colored viscous syrup.

[0107] The hyperbranched PEI was amino -terminated by attaching ethylenediamine (EDA) to ester-terminated branched PEI. 50 g (0.832 mol) of EDA was dissolved in 50 ml of methanol and the solution was cooled in dry ice. In another reaction vessel, 22.5 g (0.009 mol) of synthesized ester-terminated branched PEI was dissolved in 60 ml of methanol and the flask was also cooled in dry ice. The cold ester-terminated branched PEI solution was gradually added to the EDA solution at a certain rate at a low temperature (keeping the reaction vessel in a dry ice bath). After the addition was completed, the mixture was allowed to warm to 50°C and the reaction continued for 48 hours. The excess EDA and methanol were removed by performing rotary evaporation twice with methanol, twice with IPA, and twice with butanol at 40°C. As a result, a pale amber-colored viscous syrup was obtained.

[0108] 0.15mol of stearyl alcohol was dissolved in 25 ml of cyclohexane at 40°C. 0.005 mol of hydroquinone, 0.005 mol of p-toluene sulphonic acid, and 1.25 mol of acrylic acid were added together into a three-necked round-bottomed (RB) flask equipped with a magnetic stirrer, a reflux condenser, and a heater. In this reaction, hydroquinone and p-toluene sulphonic acid are used as inhibitor and catalyst respectively. The mixture was stirred for 8 hours at 90°C. The solvent cyclohexane was removed by rotary evaporation until a pale-yellow liquid was formed. The liquid was washed with a 5% sodium hydroxide (NaOH) solution and rinsed with Milli-Q water to remove the residues of the washing solution. Two phases: the top organic phase and bottom water phase were seen after washing the liquid with NaOH solution. The organic phase was dried in a vacuum for 24 hours at 40°C to result in stearyl acrylate.

[0109] The first generation of hyperbranched PEI was attached with stearyl acrylate to obtain the multi-arm star polymer with hyperbranched PEI core and long alkyl side chains. 0.002 mol (6.13g) of the first generation of hyperbranched PEI was dissolved in 50 ml of methanol in a beaker. The solution was transferred into a three-necked RB flask at 50°C. Stearyl acrylate (26.0 g, 0.08mol) was mixed in 50 ml of methanol in a beaker under stirring at 50°C. The above solution was then added dropwise into the hyperbranched PEI solution at 50°C for 20 minutes. The mixture was stirred for 48 hours at 50°C.

[0110] When the reaction was over, the mixture was allowed to stand for 24 hours at 25°C. Two layers with top yellow liquid and bottom white precipitated were seen. The yellow liquid was transferred into a beaker and the white precipitate was washed three times with methanol and rinsed with water to remove residues of the washing solution. The solid was dissolved in acetone and allowed to stand for 48 hours at 10°C. The white precipitate was again collected by filtration of the above mixture and washed with acetone and then dried under vacuum for 48 hours at 30°C. The sample was crushed and ground in order to prepare powders of multiarm star polymer. The preparation scheme is shown in figure 1.

[0111] Reaction Mechanism: Michael addition of the amino -terminated branched Polyethyleneimine (PEI) with alkyl acrylic esters result in an ester-terminated hyperbranched PEI. In the next step, ethylenediamine is coupled with the ester- terminated hyperbranched PEI to obtain amine-terminated hyperbranched PEI. In the final step, Michael addition reaction between alkyl acrylate and amino- terminated hyperbranched PEI result in multi-arm star polymer with hyperbranched polyethyleneimine (PEI) core and long alkyl side chains.

[0112] Ester-terminated hyperbranched Polyethylenimine

[0113] Separation and Purification: When the reaction was over, the mixture was allowed to stand for 24 hours at 25°C. Two layers with top yellow liquid and bottom white precipitated were seen. The yellow liquid was transferred into a beaker and the white precipitate was washed three times with methanol and rinsed with water to remove residues of the washing solution. The solid was dissolved in acetone and allowed to stand for 48 hours at 10°C. The white precipitate was again collected by filtration of the above mixture and washed with acetone and then dried under vacuum for 48 hours at 30°C. The sample was crushed and ground in order to prepare powders of multi-arm star polymer. The synthesis separation scheme is shown in figure 1.

[0114] Example 2: Characterization of multi-arm star polymer with hyperbranched polyalkyleneimine core and long alkyl side chains

[0115] Multi-arm star polymer with hyperbranched PEI core and long alkyl side chains were characterized by Fourier transform infrared spectroscopy (FTIR) and 1H- NMR. The IR spectra of the multi-arm star polymer are shown in figure 2.

[0116] FTIR Spectroscopy:

[0117] Fourier Transform IR measurements were carried out using Perkin Elmer Spectrum One Spectrometer. Samples were directly put between the KBr plates and loaded into the instrument. The functional groups were characterized in a region between 4000 - 450 cm1. The spectra were obtained in absorbance mode using 8 scans at 4 cm-1resolutions. The spectra were processed with OriginPro software.

[0118] NMR Spectroscopy:

[0119] 20 - 25 mg of sample was taken in an NMR tube of 5 mm diameter and then dissolved in the solvent CDCI3. Protic Solvent CDCI3 (6 7.26 ppm) was used as an internal reference for all the samples.1HNMR spectra were recorded at 400 MHz, on a Bruker (Germany) Avance III 400 Spectrometer. All NMR spectra were measured at 296.8 K. The chemical shifts were reported in ppm. The obtained NMR spectra were analyzed using TopSpin 4.1.4 (Bruker) software.

[0120] With respect to the multi-arm star polymer, the FTIR spectra (fig. 2) showed that the N-H stretching vibration absorption peak is broad and appeared at 3500-3200 cm-1 (1). The saturated C-H stretching vibration absorption peak appeared at 3000-2800 cm-1(2). The C=O stretching vibration absorption peak appeared at 1735 cm-1(3). The N-H bending vibration absorption peak appeared at 1630 cm'x(4). The C-H bending vibration absorption peak appeared at 1470 cm-1 (5). The C-N stretching vibration absorption peak appeared at 1180 cm-1(6). The C-H rocking vibration absorption peak appeared at 720 cm-1(7). The result of1H-NMR spectroscopy is shown in figure 3(a). ’ H NMR (CDCI3, 6): (1) 0.85 (t, 120H, - CH3), (2) 1.25 (m, 1200H, -O-C-(CH2)I5-), (3) 1.65 (m, 80H, -(O15-CH2-C), (4) 4.05 (t, 80H, -COO-CH2-C-), (5) 2.75 (t, 80H, N-C-CH2-CO-), (6) 2.50 (t, 80H, N-CH2-C-CO-), (7) 2.40 (t, 40H, -CON-C-CH2-N-), (8) 3.25 (t, 40H, -C-CON- CH2-), (9) 2.55 (t, 40H, N-C-CH2-CO-), (10) 2.15 (t, 40H, N-CH2-C-CO-), (11) 3.45 (t, 12H, N-C-CH2-NH-C), (12) 3.85 (t, 16H, -C-N-CH2-C-NH), (13) 3.65 (t, 48H, N-CH2-CH2-N), (14) 4.55 (t, 40H, -C-C-CONH-).

[0121] The1H NMR agreed well with the FTIR data to confirm the structure of multiarm star polymer with hyperbranched PEI core and long alkyl side chains.

[0122] Example 3: Multi-arm polymer as a carrier for curcumin:

[0123] Method A: 0.5 g of multi-arm star polymer powder having polyethyleneimine core was melted at 70°C in a vial. 0.2 g of curcumin powder was added to the polymer liquid at this temperature and stirred for 2 hours. Under these conditions, curcumin powder dissolved properly in the polymer liquid and the resulting solution becomes very viscous. The solution was allowed to cool to room temperature under slow stirring. The solution becomes a homogeneous yellow hard solid at room temperature which indicates the physical encapsulation of the curcumin drug inside the cavities of multi-arm star polymer. The yellow hard solid was crushed and ground to prepare powders of drug-polymer conjugates. In this typical example, 13 numberof curcumin molecules are attached to one molecule of multi-arm star polymer.

[0124] Method B:0.2 g of multi-arm star polymer powder was dissolved in 5 ml of chloroform at room temperature in a vial. In another vial, 0.1 g of curcumin powder was dissolved in 5 ml of chloroform. The curcumin solution was added dropwise to the multi-arm star polymer solution and stirred overnight. Under these conditions, both solutions mixed properly. The solution was left undisturbed for 2 hours. It was then dried in vacuum at 30°C overnight. Chloroform was evaporated and a homogeneous yellow solid was formed. This indicates the physical encapsulation of the curcumin drug inside the cavities of multi-arm star polymer. The yellow hard solid was crushed and ground to prepare powders of drug- polymer conjugates. In this typical example, 18 number of curcumin molecules are attached to one molecule of multi-arm star polymer.

[0125] Example 4: Multi-arm star polymer as a carrier for ibuprofen:

[0126] 0.5 g of multi-arm star polymer powder having a polyethyleneimine core was melted at 70°C in a vial. 0.05 g of ibuprofen was added to the polymer liquid at this temperature and stirred for 4 hours. Under these conditions, ibuprofen dissolved properly in the polymer liquid and the resulting solution becomes very viscous. The solution was allowed to cool to room temperature under slow stirring. The solution becomes a homogeneous hard solid at room temperature which indicates the physical encapsulation of the ibuprofen drug inside the cavities of multi-arm star polymer. The hard solid was crushed and ground to prepare powders of drug-polymer conjugates. In this typical example, 6 number of ibuprofen molecules are attached to one molecule of multi- arm star polymer.

[0127] Example 5: Multi-arm star polymer as a carrier for acetaminophen:

[0128] Method A: 0.5 g of multi-arm star polymer powder having polyethyleneimine core was melted at 70°C in a vial. 0.2 g of acetaminophen was added to the polymer liquid at this temperature and stirred for 2 hours. Under these conditions, acetaminophen dissolved properly in the polymer liquid and the resulting solution becomes very viscous. The solution was allowed to cool to room temperature under slow stirring. The solution becomes a homogeneous hard solid at room temperature which indicates the physical encapsulation of the acetaminophen drug inside the cavities of multi-arm star polymer. The hard solid was crushed and ground to prepare powders of drug-polymer conjugates. In this typical example, 35 number of acetaminophen molecules are attached to one molecule of multi-arm star polymer.

[0129] Method B:0.2 g of multi-arm star polymer powder was dissolved in 5 ml of chloroform at room temperature in a vial. In another vial, 0.05 g of acetaminophen was dissolved in 5 ml of chloroform. The acetaminophen solution was added dropwise to the multi-arm star polymer solution and stirred overnight. Under these conditions, both solutions mixed properly. The solution was left undisturbed for 2 hours. It was then dried in vacuum at 30°C overnight. Chloroform was evaporated and a homogeneous solid was formed. This indicates the physical encapsulation of the acetaminophen drug inside the cavities of multi-arm star polymer. The yellow hard solid was crushed and ground to prepare powders of drug-polymer conjugates. In this typical example, 22 number of acetaminophen molecules are attached to one molecule of multi-arm star polymer.

[0130] Example 6: Multi-arm star polymer as a clove oil carrier:

[0131] 0.2 g of multi-arm star polymer powder having polyethyleneimine core was melted at 60°C in a vial. 0.11 g of clove oil was added to the polymer liquid at this temperature and stirred for 2 hours. Under these conditions, clove oil was dissolved properly in the polymer liquid and the resulting solution becomes amber color viscous liquid. The solution was allowed to cool to room temperature under slow stirring. The solution becomes a homogeneous amber color hard solid at room temperature which indicates the physical encapsulation of the clove oil inside the cavities of multi-arm star polymer. The hard solid was crushed and ground to prepare powders of oil-polymer conjugates.

[0132] Example 7: Multi-arm star polymer as a castor oil carrier:

[0133] 0.2 g of multi-arm star polymer powder having polyethyleneimine core was melted at 60°C in a vial. 0.2 g of castor oil was added to the polymer liquid at this temperature and stirred for 4 hours. Under these conditions, castor oil was dissolved properly in the polymer liquid and the resulting solution becomes a yellow viscous liquid. The solution was allowed to cool to room temperature under slow stirring. The solution becomes a homogeneous yellow hard solid at room temperature which indicates the physical encapsulation of the castor oil inside the cavities of multi-arm star polymer. The hard solid was crushed and ground to prepare powders of oil-polymer conjugates.

[0134] Example 8: Multi-arm star polymer as a lavender oil carrier:

[0135] 0.2 g of multi-arm star polymer powder having polyethyleneimine core was melted at 60°C in a vial. 0.1 g of lavender oil was added to the polymer liquid at this temperature and stirred for 2 hours. Under these conditions, lavender oil was dissolved properly in the polymer liquid and the resulting solution becomes a pale-yellow liquid. The solution was allowed to cool to room temperature under slow stirring. The solution becomes a homogeneous pale yellow hard solid at room temperature which indicates the physical encapsulation of the lavender oil inside the cavities of multi-arm star polymer. The pale yellow hard solid was crushed and ground to prepare powders of oil-polymer conjugates.

[0136] Example 9: Multi-arm star polymer as a Neem oil carrier:

[0137] 0.2 g of multi-arm star polymer powder having polyethyleneimine core was melted at 60°C in a vial. 0.2 g of neem oil was added to the polymer liquid at this temperature and stirred for 4 hours. Under these conditions, neem oil was dissolved properly in the polymer liquid and the resulting solution becomes a yellow-brown viscous liquid. The solution was allowed to cool to room temperature under slow stirring. The solution becomes a homogeneous yellow- brown hard solid at room temperature which indicates the physical encapsulation of the neem oil inside the cavities of multi-arm star polymer. The hard solid was crushed and ground to prepare powders of oil-polymer conjugates. Example 10: Multi-arm star polymer as a demulsifier:

[0138] The multi- arm star polymer with hyperbranched PEI core and long alkyl side chains (Formula III) is used as demulsification of crude oils. Crude oil-water 5 emulsions were heated at 65°C. The multi-arm star polymer of formula III (100 ppm) was added to these emulsions at this temperature. The resulting solution was cooled to 45°C. A demulsifier (span 80 or SDS or Tween 80) was added and homogenized at 7800 RPM for 2 minutes. An 85% separation of water was achieved in crude oil-water emulsions. 0

[0139] Crude oil-water emulsions were heated at 65°C and then cooled to 45°C. A demulsifier (span 80 or SDS or Tween 80) was added alone to these emulsions at 45°C and homogenized at 7800 RPM for 2 minutes. In the absence of a multi-arm star polymer of formula III, no separation of water was achieved in crude oil- 5 water emulsions. It is therefore concluded that multi-arm star polymer increases the efficiency of the demulsification process of crude oil- water emulsions. The data on demulsification process is listed in table 1 below.

[0140] Table 1: Effect of Multi-arm star polymer on the time and efficacy of the 0 demulsification of water in waxy crude oil emulsions. In all cases, demulsifier is either 150 ppm Span 80 or 100 ppm SDS or 100 ppm Tween 80

[0141]

[0142] ADVANTAGES OF THE INVENTION

[0143] The multi-arm star polymer with hyperbranched polyalkyleneimine core and long alkyl side chains can be used in various fields.

[0144] • It acts as a de-emulsifier for separating water from water in crude oil emulsions. The efficiency of the demulsification process is seen to increase in the presence of this demulsifier the water separates easily from the emulsion. • It can be used as a drug carrier for hydrophobic drugs. As this polymer has a larger number of branches of longer carbon chain segments, more drugs can be loaded into the cavities of this polymer due to the hydrogen bonding and hydrophobic interaction with the drug molecule. As a result, smaller dosages of this polymer will be efficient in releasing a sufficient number of drug molecules at the targeted site.

[0145] • It can be used as an oil carrier for ayurvedic and other oils such as clove oil, castor oil, neem oil and lavender oil. • It can be used as a fragrance carrier for various aroma essential oils, agrumen and aliphatic aldehydes.

[0146] Further, the method of synthesizing the multi-arm star polymer has various advantages:

[0147] • The method of synthesis of multi-arm star polymer with hyperbranched polyalkyleneimine and long alkyl side chains comprises of minimum number of steps which is capable of scaling up for large-scale production.

[0148] • The method of the present invention achieves a reduction in synthesis time by starting the synthesis process with branched Polyalkyleneimine as a core material.

[0149] • This method enables synthesizing of molecules with a higher number of branches in less time when compared with those of dendrimers.

[0150] • The impurities generated during the method of synthesis of the present invention can be easily separated, thereby enhancing the purity of the synthesized novel multi-arm star polymer.

Claims

CLAIMS:

1. A multi-arm star polymer of Formula (A),characterized in having(i) a branched polyalkyleneimine core (C) of molecular weight ranging from about 400 g / mol to about 160,000 g / mol, with 15-50% ‘p’, 20-60% ‘s’ and 20- 45% ‘t’ amine groups,(ii) a plurality of short intermediate hydrocarbon units (Sh) containing amide and terminal amine functional group attached to ‘p’ or ‘p’ and ‘s’ amine groups of the poly alkyleneimine core (C);(iii) a plurality of long alkyl side-chains (Lh) are attached to the terminal amine functional group of the short intermediate hydrocarbon units (Sh), wherein, the plurality of short intermediate hydrocarbon units (Sh) is denoted by 2g-1(2p + s), and the plurality of long alkyl side-chain (Lh) is denoted by 2g(2p + s);‘p’ is the number of terminal primary amine group (-NH2), and ‘s’ is the number of secondary amine group and ‘t’ is the number of tertiary amine group in the branched poly alkyleneimine core (C);‘g’ is generation of the multi-arm star polymer, and ‘g’ = 1, 2, 3... and p>6, s>3, and wherein when ‘g’ is greater than 1, the plurality of short intermediate hydrocarbon units (Sh) attached to the core (C) is further attached to a plurality of short intermediate hydrocarbon units (Sh).

2. The multi-arm star polymer as claimed in claim 1, wherein said branched polyalkyleneimine core (C) is selected from polyethyleneimine, polypropyleneimine or polybutyleneimine.

3. The multi-arm star polymer as claimed in claim 1, wherein said plurality of short intermediate hydrocarbon units (Sh) has a molecular weight equal to or greater than 115g / mol.

4. The multi-arm star polymer as claimed in claim 1, wherein when ‘g’ is 1, said plurality of short intermediate hydrocarbon units (Sh) is attached to ‘p’ amine and ‘s’ amine of the poly alkyleneimine core (C).

5. The multi-arm star polymer as claimed in claim 1, wherein at ‘g’ greater than 1, said plurality of short intermediate hydrocarbon units (Sh) is attached to ‘p’ amine and ‘s’ amine of the polyalkyleneimine core (C) and to a plurality of short intermediate hydrocarbon units (Sh).

6. The multi-arm star polymer as claimed in claim 1, wherein said long alkyl side chain (Lh) has a molecular weight greater than 180 g / mol.

7. The multi- arm star polymer as claimed in claim 1, wherein said long alkyl side chains (Lh) is a chain of Cs-C34carbon.

8. The multi-arm star polymer as claimed in claim 1, wherein said long alkyl side chains have an acrylic ester functionality selected from the group of linear orbranched alkyl acrylates such as octyl, lauryl, palmityl, stearyl, behenyl, lignoceryl, ceryl acrylate, aryl acrylate or heteroaryl acrylates.

9. A first-generation multi-arm star polymer having a structure of formula I,Formula I wherein R is an alkyl chain with carbon number C1-C4, j. is an alkyl chain with carbon number C2-C5, R2 is an alkyl group with carbon numbers Cs to C34, and “n” is an integer between 1 and 200, preferably between 1 and 60.

10. A second-generation multi-arm star polymer having the structure of formula11,Formula II wherein, R is an alkyl chain with carbon numbers C1-C4, Ri is an alkyl chain with carbon numbers C2-C5, R2 is long hydrocarbon chain with carbon numbers Cs-C34: and “n” is an integer between 1 and 200, preferably between 1 and 60.

11. A method for preparation of the multi-arm star polymer of formula (A) as claimed in claim 1, comprising the steps of: i. attaching a plurality of short intermediate hydrocarbon units (Sh) to a branched polyalkyleneimine core (C) having ‘p’ and ‘s’ amine groups, comprising of following two sub steps of reaction:(a) reacting a branched polyalkyleneimine having core (C) having ‘p’ and ‘s’ amine groups with alkyl acrylate in a solvent at 25-50°C to produce ester- terminated hyperbranched polyalkyleneimine having a plurality of ester groups, attached to ‘p’ or ‘p’ and ‘s’ amine groups of the polyalkyleneimine core (C),(b) adding alkylene diamine to said ester-terminated hyperbranched polyalkyleneimine having a plurality of ester groups, attached to ‘p’ or ‘p’ and s amine groups of the polyalkyleneimine core (C) of step (ia) in a solvent at 25- 50°C to produce a first generation of an amino -terminated hyperbranched polyalkyleneimine having plurality of short intermediate hydrocarbon chains (Sh) attached to p and s amine groups of the polyalkyleneimine core (C),11. optionally, repeating reaction step (ia) and (ib) to first attach alkyl acrylate to said first generation amino-terminated hyperbranched polyalkyleneimine of step (ib) in a solvent at 25-50°C followed by attaching alkylene diamine in a solvent at 25-50°C to produce amino-terminated hyperbranched polyalkyleneimine having plurality of short intermediate hydrocarbon unit (Sh), attached to ‘p’ or ‘p’ and ‘s’ amine groups of the polyalkyleneimine core (C), and to plurality of short intermediate hydrocarbon units (Sh), iii. adding long chain alkyl acrylate to said amino-terminated hyperbranched polyalkyleneimine having plurality of short intermediate hydrocarbon chains (Sh) of step (i) or step (ii) in a solvent at 25-50°C to obtain two long alkyl side-chains (Lh) linked with each terminal N of an amino-terminated short intermediate hydrocarbon chain (Sh), wherein said plurality of short intermediate hydrocarbon chain (Sh) is denoted by 2g-1(2p + s), and the plurality of long alkyl side-chain (Lh) is denoted by 2g(2p + s); wherein ‘p’ is the number of terminal primary amine group (-NH2), and ‘s’ is the number of secondary amine group in the branched polyalkyleneimine core (C); wherein the optionally step (ii) can be repeated multiple times, wherein p>6, s>3, and g = 1, 2, 3, 4.

12. The method as claimed in claim 11, wherein the solvent is selected from methanol, toluene, chloroform, tetrahydrofuran.

13. The method as claimed in claim 11, wherein said step (ia) is carried out for a duration of 36-96 hrs.

14. The method as claimed in claim 11, wherein said step (ib) is carried out for a duration of 48-120 hrs.

15. The method as claimed in claim 11, wherein said step (iii) is carried out for a duration of 36-96 hrs.

16. A pharmaceutical composition comprising the multi-arm star polymer as claimed in claim 1 and an active pharmaceutical ingredient, wherein the active pharmaceutical ingredient is hydrophobic in nature.

17. The pharmaceutical composition as claimed in claim 16, wherein the active pharmaceutical ingredients are selected from curcumin, ibuprofen, paracetamol, and vitamin B 12.

18. An oil and fragrance carrier comprising the multi-arm polymer as claimed in claim 1.

19. A demulsifier for separating water from water in crude oil emulsions comprising a multi-arm star polymer as claimed in claim 1.

20. A multi-arm star polymer comprising polyethyleneimine core, having a formula III,Formula III wherein R2 is long hydrocarbon chain with carbon numbers C8-C34.

21. A multi-arm star polymer comprising polypropyleneimine core, having a formula IV,Formula IV wherein R2 is long hydrocarbon chain with carbon numbers C8-C34.

22. A multi-arm star polymer comprising polybutyleneimine core, having a formula V,wherein R2 is long hydrocarbon chain with carbon numbers C8-C34.5

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