Clay nanoparticles for medical use

Abstract

The present invention relates to a composition comprising a plurality of clay nanoparticles, each clay nanoparticle comprising an anionic component and a cationic component, the anionic component having the formula (I): [(Si8Mg b Li c )O 20 (OH)4](I), where 5.5 < b ≦ 6, and where c > 0 and b / c > 12.

Description

[Technical Field]

[0001] The present invention relates to compositions comprising clay nanoparticles, methods for making such compositions, and their use in medical and cosmetic procedures. The nanoclays can be used alone or in combination with therapeutic or diagnostic agents. For example, nanoclays can be used in the delivery of therapeutic or diagnostic agents or in regenerative medicine. [Background technology]

[0002] Clay nanoparticles are nanoparticles of layered mineral silicates that have numerous applications, including in cosmetics and paints. Clay nanoparticles are also used as excipients and active agents in the pharmaceutical industry. Depending on their chemical composition, crystalline structure, and nanoparticle morphology, clay nanoparticles are organized into several classes, including montmorillonite, bentonite, smectite, kallinite, hectorite, and halloysite.

[0003] Certain clay nanoparticles self-assemble into gels in aqueous environments, such as the body, and the resulting nanoclay gels have been found to be particularly well suited to providing a regenerative microenvironment or platform for drug delivery. An example of a nanoclay used in medical and cosmetic formulations is Laponite™ (a synthetic smectite manufactured by BYK). Laponite™ is a disc-shaped synthetic hectorite-type clay that has been cited as a potential nanomedicine for use in drug delivery, bioimaging, tissue engineering, and regenerative medicine.

[0004] Important attributes of some nanoclay gels when used as nanomedicines include ease of administration and high in vivo stability after administration. High stability is desired so that once the gel is placed at the target site, it provides a stable matrix structure onto which new cells can grow or from which drugs can be delivered. Low stability at the target site can lead to the nanoclay gel being dispersed throughout the subject, meaning that it does not fulfill its intended purpose in the correct location and can potentially cause harmful effects elsewhere in the body.

[0005] Therefore, there is a need for clay nanoparticle gels that can be effectively localized to target sites, have high stability under physiological conditions (i.e., pH 7.35-7.45 and 36.1°C-37.5°C), and can be safely and conveniently administered to and maintained in a subject. Currently known clay nanoparticles do not meet these requirements.

[0006] Some attempts have been made to address gel stability issues by creating organic nanoclay composites. However, these employ crosslinking polymer chemistries that are complex, difficult to control, and extremely time-sensitive. For clinical feasibility, more reliable formulations that can be easily manufactured are desirable.

[0007] The present inventors have surprisingly found that transparent gels with high stability in vivo can be produced from clay nanoparticles having an increased ratio of magnesium ions to lithium ions within the clay nanoparticles compared to existing nanoclays. Nanoclay gels produced from such particles can have excellent rheological properties, particularly exhibiting changes in rheological properties under physiological conditions, thus facilitating administration of the gel by injection while providing a transparent and stable gel at physiological pH. In addition, formulations containing the clay nanoparticles of the present invention can self-assemble and can be easily manufactured. Summary of the Invention

[0008] The inventors have developed a composition comprising a plurality of clay nanoparticles, each clay nanoparticle comprising an anionic component and a cationic component, the anionic component having the formula (I): [(Si8Mg b Li c )O 20 (OH)4] (I) where 5.5 < b ≦ 6 and where c > 0 and b / c > 12.

[0009] Surprisingly, the gel compositions described herein have been found to have high stability at physiological pH. Such gels can typically be easily administered by syringe without causing significant discomfort or pain to the subject. Further, the gels are stable under physiological conditions, ensuring effective localization at the target site and reducing undesired effects caused by delocalization of the gel.

[0010] A process for making the composition of the present invention is also provided by the present invention, the process comprising mixing a lithium salt solution, a magnesium salt solution, a solution containing a cationic component, and a silicate solution, and heating the solutions together until a slurry is formed.

[0011] The composition of the present invention is further provided for use in the treatment of the human or animal body by therapy or diagnosis, particularly by therapy. In particular, the composition may be for use in methods of tissue repair and / or regeneration, and / or methods of cell delivery. The composition may also be for use in the treatment or prevention of infectious diseases.

[0012] The composition of the present invention can be used in cosmetic methods. In some embodiments, the composition is a cosmetic composition, particularly a tissue filler or a topical gel or cream.

[0013] The present invention also provides a composition of the invention for use in a method of delivery of one or more therapeutic or diagnostic agents to a target site in the human or animal body, said method comprising administering said composition to the human or animal body.

[0014] The present invention has, inter alia, the features set forth in the following numbered paragraphs: 1. A composition comprising a plurality of clay nanoparticles, each clay nanoparticle comprising an anionic component and a cationic component, the anionic component having the formula (I): [(Si8Mg b Li c )O 20 (OH)4] (I) wherein 5.5 <b≦6であり、 wherein c>0 and b / c>12; composition. 2.12 3.12 4. The composition of any one of paragraphs 1-3, wherein 0.2≦c≦0.5. 5. The cationic component is Na + 5. The composition of any one of paragraphs 1 to 4, comprising: 6. The composition of any one of paragraphs 1 to 5, wherein the numbers b and c are determined by elemental analysis using inductively coupled plasma optical emission spectroscopy (ICP-OES). 7. The composition of any one of paragraphs 1 to 6, wherein the clay nanoparticles have an average size of about 15 nm to about 50 nm in their longest dimension and an average size of about 1 nm to about 3 nm in their shortest dimension. 8. The composition of any one of paragraphs 1 to 7, further comprising one or more therapeutic or diagnostic agents. 9. The composition of paragraph 8, wherein the one or more therapeutic or diagnostic agents are therapeutic or diagnostic agents suitable for use in regenerative medicine. ​​10. The composition of paragraph 8 or paragraph 9, wherein the one or more therapeutic or diagnostic agents are selected from small molecules, growth factors, antibodies, biological tissue substitutes, synthetic bone grafts, antimicrobial agents, antibiotics, and cells. 11. The composition of any one of paragraphs 1 to 10, wherein the composition comprises BMP-2. 12. The composition according to any one of paragraphs 1 to 11, wherein the composition is in solid form, preferably in powder form. 13. The composition of any one of paragraphs 1 to 11, wherein the composition is in the form of a gel or a film. 14. The composition of paragraph 13, wherein the gel exhibits a 50% change in zeta potential within the pH range of pH 6.5 to pH 8 when the zeta potential is measured using acid titration. 15. A pharmaceutical composition comprising the composition of any one of paragraphs 1 to 14, a pharmaceutically acceptable carrier or diluent, and optionally one or more pharmaceutically acceptable excipients. 16. A kit comprising a syringe or vial (e.g., a sprayable vial), wherein the syringe or vial contains the composition of paragraph 13 or paragraph 14, or the composition of paragraph 15, wherein the composition is in the form of a gel. 17. A kit comprising the composition of any one of paragraphs 1 to 7; and separately one or more therapeutic or diagnostic agents defined in any one of paragraphs 8 to 11, preferably wherein (a) the composition is in powder or gel form; and / or (b) the therapeutic or diagnostic agent is in powder form. 18. A process for making the composition of any one of paragraphs 1-15, the process comprising combining a lithium salt solution, a magnesium salt solution, a solution containing a cationic component, and a silicate solution, and heating the solutions together until a slurry is formed. 19. The process of paragraph 18, wherein the process further comprises a hydrothermal treatment step. 20. The process of paragraph 18 or paragraph 19, wherein the process further comprises drying the slurry to form a solid, and optionally the process further comprises grinding the solid to form a powder. 21. The process of paragraph 20, wherein the process further comprises adding water to the composition to form a gel. 22. The process of any one of paragraphs 18 to 21, wherein the process further comprises adding one or more therapeutic or diagnostic agents to the composition, wherein the one or more therapeutic or diagnostic agents are as defined in any one of paragraphs 8 to 11. 23. A composition according to any one of paragraphs 1 to 15 for use in the treatment of the human or animal body. 24. The composition of any one of paragraphs 1 to 15 or 23 for use in a method of regenerative medicine. 25. The composition for use according to paragraph 24, wherein the composition is for use in a method of tissue repair or regeneration, and / or cell delivery. 26. The composition of any one of paragraphs 1 to 15 or 23 for use in the treatment or prevention of an infectious disease. 27. The composition of any one of paragraphs 1 to 15 or 23, for use in a method of delivery of one or more therapeutic or diagnostic agents to a target site in the human or animal body, said method comprising administering said composition to said human or animal body, said composition comprising one or more therapeutic or diagnostic agents, and / or one or more therapeutic or diagnostic agents are administered separately to said composition in vivo at said target site. 28. A cosmetic composition comprising the composition of any one of paragraphs 1 to 14 and optionally one or more additives, preferably wherein the cosmetic composition is a tissue filler or a topical gel or cream.

[0015] References in the figures to Renovite, Renovite 1.0, or Renovite analogs refer to compositions of the invention unless otherwise specified. [Brief explanation of the drawings]

[0016] [Figure 1]Figure 1 shows a comparison of elemental ratios between Laponite™ XLG and the composition of the present invention (Renovite) set forth in Table 1. Empirically determined Mg, Li, and Na are presented relative to empirically determined Si scaled according to (Na + a[(SiMgLid)O20(OH)4]-a). Bars represent the mean and SD. P values ​​were calculated using an unpaired t-test. [Figure 2] Figure 2 shows a comparison of elemental ratios between Laponite™ XLG and various compositions of the present invention (Renovite analogs) identified in Table 2. Mg content was calculated from empirical Si, Li, and Na values ​​based on the formula: (Na + a[(SiMgLiD)O(OH)]-a. Bars represent averages. [Figure 3] Figure 3 shows the enhanced gelation of Renovite (AS-19, Table 1) in response to serum. Rheometric isotherms for the change in gel stiffness (storage modulus) in Renovite vs. Laponite™ (XLG) suspensions after exogenous exposure to simulated serum (40 mg / ml bovine serum albumin in phosphate buffered saline, pH 7.4). Exposure to simulated serum enhanced the observed increase in gel stiffness for Renovite. Measurements were performed at 25°C. [Figure 4]Figure 4 shows the enhanced gelation of a composition of the present invention (Renovite; average of all clay batches listed in Table 1) in response to serum. Rheometric analysis of Renovite versus Laponite™ (XLG) suspensions in their native state (a) and after 1 hour of exogenous exposure to simulated serum (b; 40 mg / ml bovine serum albumin in phosphate-buffered saline, pH 7.4). Renovite exhibited equivalent gel strength (yield stress (Pa)), stiffness (storage modulus (G')), and viscosity (storage modulus (G'')) to XLG in its native state. Exposure to simulated serum significantly enhanced the observed increases in gel strength, stiffness, and viscosity for Renovite. Yield stress was calculated as the inflection point (>5%) from the linear dependence of shear stress on shear strain. Histograms plot average values. Error bars = SD, N = 6, ** and **** indicate P<0.01 and P<0.0001, respectively (unpaired t-test). [Figure 5] Figure 5 shows that the enhanced gelation of compositions of the present invention (AS-13, 14, 15, 18, 19, 21, 22, 33) in response to serum correlates with Mg and Li content. The storage and loss moduli for the high and low Mg / Li compositions of the present invention specified in Table 2 and the reference sample versus Laponite™ (XLG) suspension after 1 hour of exogenous exposure to simulated serum show a significant positive correlation with the Mg / Si molar ratio (a), a significant negative correlation with the Li / Si molar ratio (b), and a slight positive trend association with the Mg / Li molar ratio. Mg content was calculated from empirical Si, Li, and Na values ​​based on the formula: (Na + a[(SiMgLi)O(OH)]-a). P values ​​are reported as Pearson's correlation coefficients, with significant correlations being P<0.05. ns = not significant. [Figure 6]Figure 6 shows the zeta potential half-maximum (PHM) and its importance for nanoclay gelation. A sharp decrease in the negative zeta potential (ZP) of the nanoclay (here, AS-14) is observed, occurring between pH 8 and pH 5 over the course of the titration with HCl. This sharp decrease in negative ZP occurs with increasing particle (aggregate) size. This indicates a phase transition in particle interactions from repulsion to attraction, which produces gels under diffusion and at high nanoclay concentrations (>2 wt%). pHPHM represents the pH at which this sharp decrease in negative ZP occurs by measuring the pH at which the negative ZP is 50% of its recorded mV before the addition of the titrant. Titrations and dynamic ZP measurements were performed on a Stabilo™ II device programmed to add 30 μl of 1 M HCl every 20 seconds. [Figure 7] Figure 7 shows the zeta potential half-maximum (PHM) for a composition of the present invention (AS-14, labeled Renovite 1.0) versus Laponite™. The PHM for Renovite occurs near physiological pH 7.4 (shaded gray) compared to pH 5.9 for Laponite™. Titrations and dynamic ZP measurements were performed on a Stabilo™ II programmed to add 30 μl of 1 M HCl every 20 seconds to a 1 wt% nanoclay suspension. [Figure 8] Figure 8 shows that zeta potential half-maximum (PHM) correlates with Mg and Li content. pH at PHM (pHPHM) for 1 wt% high and low Mg / Li compositions of the present invention (AS-13, 14, 15, 18, 19, 21, 22, labeled Renovite 1.0) and reference sample AS-33 versus Laponite™ (XLG) suspension. Significant positive correlations with Mg / Si and Mg / Li, and significant negative correlations with Li / Si were observed. The pHPHM for Renovite 1.0 occurred at pH values ​​(shaded gray) close to physiological pH 7.4. Mg content was calculated from empirical Si, Li, and Na values ​​based on the formula: (Na + a[(Si₈Mg₈Lid)O₂O(OH)₄]⁻. P values ​​are reported as Pearson's correlation coefficients, with significant correlations being P<0.05.

[0017] Detailed Description of the Invention Clay nanoparticles for medical use The clay nanoparticles described herein are inorganic nanoparticles. The clay nanoparticles may comprise or consist of silicates. The silicates may include layered silicates.

[0018] The clay nanoparticles may have an average size of about 15 nm to about 50 nm in their longest dimension. The clay nanoparticles may have an average size of about 20 nm to about 40 nm in their longest dimension. For example, the clay nanoparticles may have an average size of about 15 nm to about 40 nm, or about 20 nm to about 50 nm, or about 24 nm to about 36 nm in their longest dimension.

[0019] The clay nanoparticles may have an average thickness (shortest dimension) of about 1 nm to about 3 nm. For example, the clay nanoparticles may have an average thickness of about 1 nm to about 2.5 nm, or about 1.5 nm to about 2.5 nm, or about 1.3 nm to about 2.2 nm.

[0020] The size of the clay nanoparticles can be determined by any suitable method known to those skilled in the art. Typically, the size is determined using small angle X-ray scattering. The size of the clay nanoparticles can be determined when dispersed in an aqueous environment.

[0021] The clay nanoparticles may have an aspect ratio of at least 1:5. For example, the clay nanoparticles may have an aspect ratio of at least 1:10, or at least 1:20, or at least 1:25. The clay nanoparticles may have an aspect ratio of less than 1:100. For example, the clay nanoparticles may have an aspect ratio of less than 1:50 or less than 1:30. The clay nanoparticles may have an aspect ratio of 1:10 to 1:50. For example, the clay nanoparticles may have an aspect ratio of 1:5 to 1:30 or 1:10 to 1:30.

[0022] Each clay nanoparticle of the present invention comprises an anionic component and a cationic component. The anionic component has the formula (I): [(Si8Mg b Li c )O 20 (OH)4] (I) has

[0023] The anionic component of the clay nanoparticles is negatively charged. Typically, this negative charge is a−, where a is equal to the positive charge carried by the cationic component. a is greater than 0 and does not necessarily have to be an integer value.

[0024] In formula (I) above, b represents the number of Mg atoms present per unit of the anionic component. b does not necessarily have to be an integer value. b is typically ≦6.0. More typically, b≦5.9. b is typically ≧5.6, preferably 5.5≦b≧6.0, for example 5.6≦b≧6.0 or 5.6≦b≧5.9.

[0025] In formula (I) above, c represents the number of Li atoms present per unit of the anionic component. c is greater than 0 and does not necessarily have to be an integer value. c is typically ≦2, more typically ≦1. Preferably c is ≦0.5, more preferably c≦0.45, for example c can be ≦0.4. c is typically ≧0.2, more typically ≧0.3. Thus, typically, 0<c≦2, 0<c≦1, 0<c≦0.5, 0<c≦0.4, 0.2≦c≦2, 0.2≦c≦1, 0.2≦c≦0.5, 0.2≦c≦0.45, 0.3≦c≦0.5, or 0.3≦c≦0.45. In some preferred embodiments 0.2≦c≦0.5, and in particularly preferred embodiments 0.3≦c≦0.5.

[0026] The ratio b / c is greater than 12. Typically, the ratio is typically 12

[0027] The numbers b and c are preferably determined using elemental analysis using inductively coupled plasma optical emission spectroscopy (ICP-OES). Example 2 described herein provides further details of a suitable method for determining these values ​​using elemental analysis.

[0028] The cationic component of each clay nanoparticle typically comprises one or more metal cations. In some embodiments, the cationic component comprises one or more metal cations selected from alkali metal cations, alkaline earth metal cations, transition metal cations, and combinations thereof. Such metal cations may comprise one or more cations of lithium, sodium, calcium, copper, potassium, or magnesium. Sodium is preferred.

[0029] Typically, the metal cation has the formula M n+ where M is a metal and n is an integer, typically an integer from 1 to 6, more typically from 1 to 4. Preferably, n is 1 or 2, more preferably 1. M n+ is preferably Na + is.

[0030] Thus, typically, the clay nanoparticles have the formula: [(M n+ ) x (M2 p+ ) y ][(Si8Mg b Li c )O 20 (OH)4]​a- wherein b, c, and a are as defined anywhere herein, and wherein M n+ and M2 p+ are different metal cations, and n and p are the same or different and are integers between 1 and 6, typically 1 or 2. Typically, the charge is balanced such that nx + py = a. x and y need not be integers and may be the same or different. The sum of x and y is greater than 0. Typically, the sum of x and y (i.e., x + y) is ≦2, more typically ≦1. In some preferred embodiments, x + y is ≦0.7, more preferably x + y is ≦0.5. Typically, x + y is ≧0.3, more typically ≧0.4. Thus, in some embodiments, 0<(x+y)≦2, for example, 0<(x+y)≦1, 0<(x+y)≦0.7, 0<(x+y)≦0.5, 0.2≦(x+y)≦0.7, 0.3≦(x+y)≦0.7, 0.4≦(x+y)≦0.7, 0.3≦(x+y)≦0.5, or 0.4≦(x+y)≦0.5. In some preferred embodiments, 0.2≦(x+y)≦0.7, more preferably 0.3≦(x+y)≦0.5.

[0031] In some embodiments, the cationic component of the clay is such that the clay nanoparticles have the formula: (M n+ ) z [(Si8Mg b Li c )O 20 (OH)4] a- where n is an integer from 1 to 4, typically 1 or 2, more typically 1, and z is equal to a / n. n+ Na + whereby the clay nanoparticles have the formula: (Na + ) a [(Si8Mg b Li c )O 20 (OH)4] a- having, wherein a, b, and c are as defined anywhere herein.

[0032] The nanoparticles of the present invention may contain impurities and / or by-products. The nanoparticles preferably have a purity of 90%, more preferably 95%, more preferably 98% or 99%. Most preferably, the nanoparticles are substantially pure particles of the formula [(Si8Mg b Li c )O 20 (OH)4].

[0033] The composition of the present invention The composition of the present invention includes a plurality of clay nanoparticles, each clay nanoparticle includes an anionic component and a cationic component, and the anionic component has the formula (I): [(Si8Mg b Li c )O 20 (OH)4] (I) having, wherein 5.5 < b ≤ 6, and wherein c > 0 and b / c > 12.

[0034] As used herein, a plurality of clay nanoparticles refers to two or more clay nanoparticles.

[0035] The composition of the present invention may contain up to 100 wt% of the clay nanoparticles of the present invention. More typically, it contains up to 8,5 wt% of the clay nanoparticles of the present invention, or up to 5,0 wt% of the clay nanoparticles of the present invention. Typically, the composition contains at least 0.1 wt%, for example 0.1 - 100 wt%, 0.1 - 85 wt%, or 0.1 - 50 wt% of clay nanoparticles.

[0036] The clay nanoparticles described herein may contain coordinated water. Accordingly, reference herein to clay nanoparticles of the present invention is intended to encompass clay nanoparticles having coordinated water. Furthermore, reference herein to a dry composition is intended to encompass compositions comprising clay nanoparticles containing coordinated water. Thus, the dry composition may contain up to 10 wt% water. More typically, it contains up to 7 wt% water. Typically, the composition contains at least 3 wt% water, or at least 5 wt% water. Typically, therefore, the composition may contain 3 wt% to 10 wt% water, such as 5 wt% to 7 wt% water. In such embodiments, the remainder of the composition may contain up to 100 wt% clay nanoparticles of the present invention, such that the composition contains, for example, 93 wt% to 95 wt% clay nanoparticles of the present invention.

[0037] The composition can consist of or consist essentially of the clay nanoparticles of the present invention. In such embodiments, the composition is typically in a dry form, such as a powder, film, granules, coating, porous sponge, or fiber. The composition can contain, for example, at least 90% clay nanoparticles, at least 95% clay nanoparticles, at least 98% or 99% clay nanoparticles, or about 99.5% clay nanoparticles. Alternatively, additional materials can be present in the composition, including, for example, a carrier or diluent (e.g., water or saline), an excipient, and / or a therapeutic or diagnostic agent. In embodiments in which the composition is in powder form, for example, the composition can further contain additional materials such as ions, proteins, and polymers.

[0038] In some preferred embodiments, the compositions of the present invention are in a dry form, such as a powder. The compositions can be lyophilized, such as a lyophilized powder. An alternative dry form is a film. In some embodiments, for example, when water or saline is present in the composition, the composition is a liquid-solid fluid mixture, such as a slurry or paste. In some embodiments, for example, when water or saline is present in the composition, the composition is in the form of a gel. A gel is a preferred form of the compositions of the present invention, and the compositions are typically administered in this form.

[0039] The gel of the present invention can be formed, for example, by placing clay nanoparticles in water. The gel of the present invention can be dried to form a film or can be freeze-dried. When the composition is provided as a film or in a freeze-dried form, it can be administered by applying it to a surface. Alternatively, it can be reconstituted with a diluent such as water or saline before use.

[0040] The composition may be a pharmaceutical composition, which is a composition suitable for pharmaceutical use. Pharmaceutical compositions typically contain one or more pharmaceutically acceptable excipients. Preferred pharmaceutical compositions are sterile and pyrogen-free.

[0041] Suitable carriers and / or diluents for use in the present invention include pharmaceutically acceptable carriers such as water and aqueous solutions, especially saline. Isotonic solutions, especially isotonic saline, are preferred. Carriers or diluents are typically sterile. Therefore, sterile isotonic saline is a preferred carrier. Such carriers can be used in the case of compositions in the form of slurries or gels.

[0042] If necessary, excipients can also be included in the composition.Those skilled in the art will be familiar with suitable excipients that can be useful for inclusion.In one embodiment, when the composition further comprises a therapeutic agent and / or a diagnostic agent, for example, a second carrier material for the therapeutic agent or diagnostic agent can be used.The second carrier can be a polymer material.In some preferred embodiments, the second carrier is selected from carboxymethylcellulose, gelatin, and collagen.

[0043] For drugs in solid form, diluents such as lactose, dextrose, sucrose, cellulose, corn starch, or potato starch; rheology modifiers such as carboxymethylcellulose, gelatin, and collagen; lubricants such as silica, talc, stearic acid, magnesium or calcium stearate, and / or polyethylene glycol; binders such as starch, gum arabic, gelatin, methylcellulose, carboxymethylcellulose, or polyvinylpyrrolidone; dissociating agents such as starch, alginic acid, alginates, or sodium starch glycolate; effervescent mixtures; dyes; wetting agents such as lecithin, polysorbates, lauryl sulfate, and the like; dispersing agents such as sodium polyacrylate and pyrophosphate; and non-toxic and pharmacologically inactive substances generally used in pharmaceutical formulations.

[0044] For liquid forms such as syrups, rheology modifiers such as carboxymethylcellulose, gelatin, and collagen; carriers such as sucrose or sucrose with glycerin and / or mannitol and / or sorbitol.

[0045] For suspensions or emulsions, a carrier, for example a natural gum, agar, sodium alginate, pectin, methylcellulose, carboxymethylcellulose, or polyvinyl alcohol.

[0046] For injectable forms, sterile water, as already mentioned above, as well as rheology modifiers such as carboxymethylcellulose, gelatin, and collagen; olive oil; ethyl oleate; glycols, such as propylene glycol; and, if desired, an appropriate amount of lidocaine hydrochloride.

[0047] A preferred composition of the present invention comprises the nanoparticles of the present invention and water, wherein the nanoparticles are present in an amount of about 0.1 wt% to about 50 wt% based on the total weight of the composition. A preferred composition comprises about 0.5 wt% to about 40 wt% of the nanoparticles of the present invention based on the total weight of the composition. For example, the composition may comprise from about 1 wt% or from about 2 wt% to up to about 40 wt% of the nanoparticles of the present invention. The composition typically also comprises water or saline. The composition may optionally contain one or more additional additives. The composition may consist of or consist essentially of the nanoparticles of the present invention and water or saline.

[0048] A preferred composition of the present invention is a gel, particularly a pharmaceutically acceptable gel. The gel typically contains the nanoparticles of the present invention in an amount of about 2 wt% to about 12 wt% based on the total weight of the gel. The gel may further contain water in an amount of about 80 wt% to about 98 wt%, for example, about 85 wt% to about 96 wt% or about 88 wt% to about 94 wt%.

[0049] If the gel contains more than 7 wt% of the nanoparticles of the present invention, the nanoparticles may not be adequately dispersed. In this case, the gel may also contain a dispersing agent, such as pyrophosphate or sodium polyacrylate. In embodiments in which a dispersing agent is present in the gel, the gel may contain the nanoparticles of the present invention in an amount of up to approximately 12 wt% of the total weight of the gel. For example, when a dispersing agent is present, the gel may contain the nanoparticles of the present invention in an amount of about 2 wt% to about 12 wt%, about 4 wt% to about 10 wt%, or about 7 wt% to about 10 wt%. Such gels may further contain water in an amount of about 80 wt% to about 98 wt%, e.g., about 85 wt% to about 96 wt%, or about 88 wt% to about 93 wt%.

[0050] Compositions that do not contain a dispersant, e.g., compositions consisting of or consisting essentially of nanoparticles of the present invention and water, typically form gels when the nanoparticles are present in an amount of up to about 7 wt% based on the total weight of the gel. Thus, in embodiments in which a dispersant is not present, for example, when a composition consists essentially of nanoparticles of the present invention and water, the gel typically contains nanoparticles of the present invention in an amount of about 2 wt% to about 7 wt% of the total weight of the gel. Often, the gel contains nanoparticles of the present invention in an amount of about 2 wt% to about 4 wt% of the total weight of the gel. In one embodiment, the gel contains nanoparticles of the present invention in an amount of about 4 wt% to about 5 wt%. In another embodiment, the gel contains nanoparticles of the present invention in an amount of about 5 wt% to about 6 wt%. In this case, the water content of the gel can be about 93 wt% to about 98 wt%, such as about 96 wt% to about 98 wt%, based on the total weight of the gel.

[0051] The composition of the present invention may alternatively be a paste. Typically, when the composition is a paste, the composition comprises the nanoparticles of the present invention in an amount of 7 wt% to 50 wt%, such as 10 wt% to 40 wt%, or 20 wt% to 30 wt%, of the total weight of the composition.

[0052] The composition of the present invention may alternatively be a sol. Typically, when the composition of the present invention is a sol, the composition comprises the nanoparticles of the present invention in an amount of 0.1 wt% to 2 wt%, such as 0.5 wt% to 2 wt%, or 1 wt% to 2 wt%, of the total weight of the composition.

[0053] The compositions of the present invention are typically biodegradable. The term biodegradable is understood to mean that the composition has the ability to degrade over time within human or animal tissues or bodies and / or in the environment. The time for complete degradation can be at least 1 week, at least 1 month, at least 2 months, at least 6 months, or at least 12 months. The time for complete degradation can be 12 months or less, or 6 months or less. For example, the time for complete degradation can be 1 week to 12 months, 1 week to 6 months, 1 month to 12 months, 1 month to 6 months, 2 months to 12 months, or 2 months to 6 months. The degradation time can affect how quickly a drug is released from the gel in situ in the body. Thus, the degradation time can desirably vary depending on any therapeutic or diagnostic agents present in the composition.

[0054] When the composition is a gel, the gel preferably exhibits a 50% change in zeta potential within the pH range of pH 6.5 to pH 8. A 50% change in zeta potential is defined as a change in the measured zeta potential of at least 50% compared to the baseline zeta potential upon titration with acid. The baseline zeta potential is the zeta potential of the gel without pH adjustment, i.e., before the addition of acid. The baseline zeta potential is typically measured at pH 9 to pH 11, more typically pH 9.5 to pH 10.5, and more typically about pH 10.

[0055] The change in zeta potential is typically a decrease in the magnitude of the zeta potential value, i.e., the absolute value of the zeta potential tends toward zero. This indicates an increase in the stability of the gel. Zeta potential values ​​can be positive or negative. In either case, a decrease in the absolute value indicates a value approaching zero.

[0056] Preferably, the 50% change in zeta potential occurs in the pH range of 7 to 7.8, more preferably in the pH range of 7.2 to 7.8. In a particularly preferred embodiment, the 50% change in zeta potential of the gel occurs within the pH range of 7.3 to 7.5.

[0057] Typically, the change in zeta potential is measured by titrating the gel with an acid such as hydrochloric acid. The change in zeta potential can be determined using any suitable method known in the prior art. For example, it can be determined using an instrument designed to measure zeta potential, such as the Stabilo Zeta™ kit. Typically, the zeta potential is measured using a solution of nanoparticles in water, typically a 1 wt% solution of nanoparticles in ultrapure water. Zeta potential is a measure of the electrokinetic potential of particles in a colloidal system and can be used as an indicator of gel stability. Particles with a large negative zeta potential are thought to tend to repel each other. However, a low negative zeta potential indicates little repulsive force between particles. Therefore, the particles of the present invention preferably have a negative zeta potential that is less than 50% of its absolute value at a pH within the physiological range. This means that the gel is in its most stable state within the physiological pH range.

[0058] The gels of the present invention typically have a pH of approximately 10 in the absence of rheology or pH modifiers. At this pH, the gel typically has a very negative zeta potential, meaning that the particles repel each other and are more fluid, making them relatively easy to administer, for example, by injection. However, upon contact with body fluids or other physiological pH environments, a change in zeta potential occurs, typically reducing the repulsive forces between particles. Thus, the stability or rigidity of the gel increases, thus providing a firmer, more stable gel at the site of delivery. This further gelation may be the result of new attractive interactions as a result of increased ionicity. Furthermore, when it is in contact with body fluids, proteins diffusing into the gel may bind and form crosslinks between particles, further stabilizing the gel. The increased stability helps retain the gel at the site of administration and avoid off-target side effects.

[0059] Therapeutic or diagnostic agents The compositions of the present invention may further comprise one or more therapeutic or diagnostic agents. The therapeutic or diagnostic agent may be a small molecule therapeutic or diagnostic agent, including a small molecule drug, a prodrug, or a dye or colorant. The therapeutic or diagnostic agent may alternatively be a biologic, which may be an amino acid, a signaling molecule, a peptide, a protein (which may be a recombinant protein or a naturally occurring protein), an antibody, a nucleic acid, an oligonucleotide (such as an aptamer), or a cell. The therapeutic or diagnostic agent may alternatively be a polymeric material. Combinations of one or more therapeutic or diagnostic agents may be used.

[0060] The nanoclay compositions of the present invention can be used to deliver a wide variety of different therapeutic or diagnostic agents, and the nature of the agent used is not particularly limited. Exemplary therapeutic agents include antimicrobial agents (e.g., antibiotics), growth factors, antibodies, nutrients, enzymes, hormones, steroids, biological tissue substitutes, synthetic tissue substitutes, aptamers, and cells. Exemplary diagnostic agents include dyes, colorants, radioisotopes (which may be for x-ray detection and / or decomposition monitoring), contrast agents (such as CT contrast agents, such as iodine-containing contrast agents and barium sulfate; MRI contrast agents, such as gadolinium (III), iron oxide, iron platinum, and manganese; or ultrasound contrast agents), or fluorescent molecules. Combinations of two or more therapeutic agents can be used. Combinations of two or more diagnostic agents can be used. One or more therapeutic agents can be used in combination with one or more diagnostic agents.

[0061] In one embodiment, the one or more therapeutic or diagnostic agents are agents useful in regenerative medicine. In some embodiments, the one or more therapeutic or diagnostic agents are selected from growth factors, antibodies, biological tissue substitutes, synthetic bone grafts, and cells. In addition to or instead of such therapeutic agents, an antimicrobial agent may be included in the composition. Any antimicrobial agent may be used. Examples include antibiotics such as vancomycin, gentamicin, tobramycin, and chlorhexidine.

[0062] Typically, the biological tissue substitute can be a soft tissue substitute, such as bone marrow or plasma, or a hard tissue substitute, such as bone. Examples of biological tissue substitutes include platelet-rich plasma (PRP) and biological bone graft substitutes.

[0063] Typically, the synthetic tissue substitute can be a synthetic bone graft. The synthetic bone graft comprises calcium salts, such as calcium sulfate or calcium phosphate, either alone or in combination. β-tricalcium phosphate (β-TCP) is a preferred calcium phosphate. Hydroxyapatite (HA) is a more preferred calcium phosphate.

[0064] Typically, the cells may be somatic cells, such as chondrocytes; progenitor cells; or stem cells, such as mesenchymal stem cells. Cells may also be provided as bone marrow aspirate (BMA).

[0065] Typically, the protein is a recombinant protein. Any protein for use in regenerative medicine can be used. Typically, the recombinant protein is a growth factor, such as bone morphogenetic protein (BMP), platelet-derived growth factor (PDGF), transforming growth factor (TGF), fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF), or insulin-like growth factor (IGF). A combination of two or more such growth factors can be used.

[0066] Aptamers, as referred to herein, are short synthetic ssDNA or ssRNA sequences. Aptamers can be therapeutic or diagnostic aptamers, such as aptamers that interact with biomarkers. Such aptamers can further include diagnostic features, such as fluorescent markers or radioisotopes.

[0067] In some preferred embodiments, the composition comprises a BMP or a BMP analog, such as an AMP. Examples may include BMP-2, BMP-3, BMP-4, BMP-6, BMP-7, and BMP-8, or heterodimers thereof. AMP-2 is an example of a suitable analog of BMP-2. More preferably, the composition comprises BMP-2 and / or BMP-7, and analogs thereof, particularly BMP-2 and / or BMP-7. Most preferably, the composition comprises BMP-2 and analogs thereof, particularly BMP-2.

[0068] Alternatively, the one or more therapeutic or diagnostic agents may be for use in treating or diagnosing diseases and disorders other than those related to regenerative medicine. For example, the compositions of the present invention may be for use in delivering therapeutic and / or diagnostic agents suitable for treating or diagnosing cancer. For example, diagnostic agents that exhibit chemiluminescence, fluorescence, or contain radioisotopes may be used. Suitable therapeutic agents include one or a combination selected from doxorubicin, β-lapachone, or methotrexate.

[0069] The compositions typically contain a diagnostically visible and / or therapeutically effective amount of one or more diagnostic or therapeutic agents, respectively, which can be determined by one skilled in the art based on the nature of the agent and the size and weight of the subject.

[0070] In embodiments in which a BMP is provided as a therapeutic agent, the BMP may be provided in a dose of about 0.01 μg to about 50 mg, e.g., about 0.1 μg to about 20 mg, or about 1 μg to about 15 mg total dose. One of skill in the art will appreciate that the dose may depend on the clinical situation, such as the size of the area to be treated or the total volume of the composition.

[0071] The use of clay nanoparticles for BMP delivery provides dosage control, allowing low doses of BMP (e.g., 0.1 to 300 μg) to be used to stimulate bone formation at the defect, or higher doses (e.g., 10 μg to approximately 25 mg or 300 μg to approximately 15 mg) to be used with reduced risk of off-target effects. Studies have demonstrated significant adverse effects associated with higher doses of BMP and poor local retention, such as heterotopic ossification, osteolysis, and swelling. Therefore, allowing for lower BMP doses or ensuring retention of the protein at the target site promotes fracture healing and joint fixation without the precipitation of serious adverse effects. Targeted administration of BMP, facilitated by the high stability and rigidity of the gel provided by the present invention, also reduces the adverse off-target side effects of BMP.

[0072] When the composition contains one or more therapeutic and / or diagnostic agents, the therapeutic and / or diagnostic agents can be provided in combination with a pharmaceutically acceptable carrier, referred to herein as a second carrier.Any suitable drug carrier can be used, and those skilled in the art will be familiar with the selection of suitable carriers and excipients for the therapeutic and diagnostic agents that can be used in the present invention.Typically, the carrier can be selected from carboxymethylcellulose, gelatin, and collagen.Additional excipients can be optionally incorporated.

[0073] In some embodiments, the composition does not include an additional diagnostic and / or therapeutic agent.

[0074] kit Also provided herein are kits comprising compositions or pharmaceutical compositions according to the invention.

[0075] In some embodiments, the kit of the present invention includes a syringe, for example, a pre-filled syringe, in which the syringe contains the composition described herein, and the composition is in the form of a gel. In some embodiments, the kit may include a syringe and the composition of the present invention separately. In such embodiments, the composition may be in gel form and stored in a container such as a pouch. In other such embodiments, the composition may be in a form that can be a precursor to the gel form, typically a solid form such as a powder, typically a lyophilized powder that can be hydrated to form a gel.

[0076] In some embodiments, the kits of the invention include a vial, which may be a sprayable vial, for example a pre-filled vial containing a composition of the invention described herein.

[0077] In some embodiments, the kits of the invention may include one or more therapeutic or diagnostic agents, as defined anywhere herein. The therapeutic and / or diagnostic agents may be provided separately from the compositions of the invention, or they may be provided in the compositions of the invention.

[0078] Preferably, the composition is in powder form or in gel form; and / or the therapeutic or diagnostic agent is in powder form. If the composition is in powder form, use of the kit may involve hydrating the powder to form a gel.

[0079] The composition of the invention and the therapeutic and / or diagnostic agent may be provided in forms suitable for separate administration.

[0080] Alternatively, one or more therapeutic and / or diagnostic agents may be provided in a form suitable for addition to the gel prior to administration to a subject. Alternatively, the drug and composition may be premixed in dry form, and use of the kit may involve hydration of the mixture to form a gel suitable for administration.

[0081] The kit may include a biological implant and the composition of the present invention. In one embodiment, the biological implant is pre-coated with a gel or dry film as described herein. Alternatively, the composition (e.g., gel or dry film) and the implant may be provided separately. The biological implant referred to herein may be a medical device such as a pacemaker, an implantable cardioverter defibrillator, or a contraceptive implant; or a prosthetic implant such as a knee, hip, or shoulder replacement, or a medical screw or other fixation device.

[0082] The kit may include a gel of the present invention in the form of a dehydrated film. The kit may further include a device for hydrating the film. Use of such a kit may involve administering the film, for example, by application to the skin, and then hydrating the film.

[0083] In some embodiments, the kit may include a composition in granular or particulate form.

[0084] The kit may also include instructions for use.

[0085] therapeutic use The compositions described anywhere herein may be for use in the treatment of the human or animal body.

[0086] In one embodiment, the subject is mammal, particularly human.However, it can be non-human.Preferred non-human animals include but are not limited to primates such as marmosets or monkeys, commercially raised animals such as horses, cows, sheep or pigs, and pets such as dogs, cats, mice, rats, guinea pigs, ferrets, gerbils or hamsters.

[0087] In one embodiment, the composition is for use in a method of regenerative medicine.

[0088] Thus, the present invention also provides the use of a composition of the invention for the manufacture of a medicament for use in a method of regenerative medicine.

[0089] The present invention also provides a method of regenerative medicine, comprising administering to a subject an effective amount of a composition of the present invention.

[0090] As described herein, regenerative medicine includes tissue repair and regeneration, which may include tissue formation and / or fusion. This may include the repair or regeneration of soft tissues, including muscle (smooth, skeletal, and cardiac muscle), fat, fibrous tissues (connective tissue, cartilage, tendons, and ligaments), synovial tissue, blood vessels (arteries, veins, and capillaries), lymphatic vessels, skin, and nerves. Regenerative medicine also includes the repair and regeneration of hard tissues, including bone, tooth enamel, dentin, and cementum.

[0091] Tissue repair and regeneration also includes tissue replacement, such as filling voids left by tumors.

[0092] Preferably, the regenerative medicine method is the repair or regeneration of skin, bone, and / or cartilage.

[0093] The method of regenerative medicine can be a method of wound repair. For example, the one or more drugs that can comprise the composition can be for use in wound repair and for preventing or treating coexisting conditions, such as inflammation, infection, and pain, that are often present in those requiring wound repair.

[0094] In some cases, regenerative medicine may involve the delivery of cells, such as the delivery of somatic cells, such as chondrocytes; progenitor cells; or cells to regenerate tissue, such as the delivery of stem cells, such as mesenchymal stem cells.

[0095] Thus, the compositions of the present invention may be for use in methods of tissue repair or regeneration, and / or cell delivery.

[0096] Thus, the present invention also provides the use of a composition of the invention for the manufacture of a medicament for use in tissue repair or regeneration, and / or cell delivery.

[0097] The present invention also provides a method of tissue repair or regeneration and / or cell delivery, said method comprising administering to a subject an effective amount of a composition of the present invention.

[0098] In some cases, the compositions of the invention may be for use in the treatment or prevention of infectious diseases.

[0099] Thus, the present invention also provides the use of a composition of the invention for the manufacture of a medicament for use in the treatment or prevention of an infectious disease.

[0100] The present invention also provides a method for treating or preventing an infectious disease, said method comprising administering to a subject an effective amount of a composition of the present invention.

[0101] The compositions of the present invention may also be for use in a method for delivering one or more therapeutic or diagnostic agents to a target site in a human or animal body, the method comprising administering the composition to the human or animal body, wherein the composition comprises one or more therapeutic or diagnostic agents, and / or the one or more therapeutic or diagnostic agents are administered separately to the composition in vivo at the target site. The therapeutic or diagnostic agent for delivery may be any therapeutic or diagnostic agent described herein. In some embodiments, the therapeutic or diagnostic agent is a cell. In some embodiments, the therapeutic or diagnostic agent is an agent useful in regenerative medicine. In some embodiments, the therapeutic or diagnostic agent, such as doxorubicin, β-lapachone, or methotrexate, is useful in the treatment of cancer, i.e., cancer therapy. In such embodiments, the target site may typically be a tumor.

[0102] The compositions and pharmaceutical compositions of the present invention can be administered in a variety of dosage forms. The compositions and pharmaceutical compositions of the present invention can be administered parenterally, for example, subcutaneously, intravenously, intramuscularly, intrasternally, or transdermally. Typically, the compositions of the present invention are administered by injection or applied to an exposed target site. For example, the compositions can be administered directly to the surface of the subject to be treated, i.e., the surface is coated with the compositions of the present invention (e.g., by spray coating the surface to be treated); or the compositions can be administered directly to a void in the tissue of the subject, i.e., filling or partially filling the void. Alternatively, the compositions of the present invention can be delivered through a fixed entry point, for example, via a cannula.

[0103] When the composition of the present invention is in the form of a gel or dry film, it can be directly administered to a wound, for example, a skin wound or a burn, by covering the wound with the gel or film. Alternatively, the composition of the present invention can be applied to the wound by spraying. Then, additional dressings such as gauze and / or bandages can be applied. Alternatively, the gel or film can be incorporated into a bandage, i.e., the bandage can include the gel or dry film of the present invention.

[0104] The composition can also be provided as a coating on medical device, and can be provided to subject together with the device.When the composition is provided as a dry film, the composition can be rehydrated after the device is inserted.Suitable medical devices include pacemakers, implantable cardioverter defibrillators, or contraceptive implants; or prosthetic implants such as knee, hip, or shoulder replacements, or medical screws or other fixators.

[0105] In embodiments in which one or more therapeutic or diagnostic agents are used, the one or more therapeutic or diagnostic agents can be administered as a single composition comprising the nanoparticles described herein and the therapeutic and / or diagnostic agent(s). Alternatively, the one or more therapeutic or diagnostic agents can be administered separately, subsequent to, or sequentially with administration of the gel. Separate, subsequent, or sequential administration of the one or more therapeutic or diagnostic agents can include administration to the gel on the target surface or injection into the gel at the target site.

[0106] In such embodiments, one or more therapeutic or diagnostic agents may be added in a therapeutically effective amount. The one or more therapeutic or diagnostic agents may be added in a single administration or via multiple administrations. In some embodiments, the one or more therapeutic or diagnostic agents may be added in situ at the target site to provide sustained delivery of the one or more therapeutic or diagnostic agents. The one or more therapeutic or diagnostic agents may be added in 1 to 10 administrations, typically 1 to 6 administrations, and more typically 1 to 4 administrations. There is no limit to the number of administrations that may be provided, provided that the composition is not saturated. Thus, administration may continue until such time as treatment of the subject is complete.

[0107] In some embodiments, the compositions of the invention do not include any additional therapeutic and / or diagnostic agents. In such embodiments, the compositions may be administered via multiple administrations, such as 1 to 10 administrations, typically 1 to 6 administrations, and more typically 1 to 4 administrations.

[0108] When one or more therapeutic or diagnostic agents are added to the composition in multiple doses, there is no specific time lapse between each dose, which can be determined by one skilled in the art of administering the one or more therapeutic or diagnostic agents and will depend on such aspects as the half-life of the therapeutic or diagnostic agent in question and its rate of release from the gel.

[0109] A therapeutically effective amount of the composition of the present invention is administered to a patient. Typical doses can be determined by those skilled in the art according to the activity of the particular composition, the age, weight, and condition of the subject to be treated, the type and severity of the disease, and the frequency and route of administration.

[0110] cosmetic use The compositions described anywhere in this specification can be used in cosmetic methods. Suitable methods include using them as topical cosmetic creams or gels, or as cosmetic tissue fillers, such as lip fillers or dermal fillers, to moisturize the skin, improve the evenness of skin tone, and prevent or reduce wrinkles or skin markings. In some preferred embodiments, the composition is used as a cosmetic tissue filler. Alternatively, it can be used in a topical cosmetic cream.

[0111] Therefore, any composition described herein may be a cosmetic composition, which is a composition suitable for cosmetic use. The cosmetic composition typically contains one or more additives useful in formulating the cosmetic composition. The cosmetic composition may be a tissue filler, or a topical cream or gel.

[0112] Typically, when the composition of the present invention is a cosmetic composition or is used in a cosmetic application, it does not contain any additional diagnostic or therapeutic agents.

[0113] The cosmetic compositions of the present invention may optionally include an anti-inflammatory agent to reduce swelling. In some embodiments, the anti-inflammatory agent is not present in the cosmetic composition. In some embodiments, the cosmetic composition does not include any therapeutic agent.

[0114] Process for making clay nanoparticles and compositions Processes for making the clay nanoparticles and compositions of the present invention are also provided herein.

[0115] Typically, the process involves combining a lithium salt solution, a magnesium salt solution, a solution containing a cationic component, and a silicate solution. Such salt solutions used in the process of the present invention can be any suitable aqueous solution known to those skilled in the art.

[0116] Typically, the molar ratio of magnesium to lithium introduced into the combined solution (Mg 投入 / Li 投入 ) is 2 to 30, such as 5 to 25 or 10 to 25.

[0117] The lithium salt solution may be a lithium sulfate solution, a lithium chloride solution, a lithium hydroxide solution, a lithium nitrate solution, or a combination thereof. Typically, a lithium sulfate solution is used. The process for producing the clay nanoparticles and compositions of the present invention may first involve dissolving a lithium salt in water to form an aqueous solution. The salt may be a hydrated salt, such as a monohydrate. In some embodiments, the process involves dissolving lithium sulfate monohydrate in water.

[0118] The magnesium salt solution may be a magnesium sulfate solution, a magnesium chloride solution, a magnesium nitrate solution, or a combination thereof. Typically, a magnesium sulfate solution is used. The process for producing the clay nanoparticles and compositions of the present invention may first involve dissolving a magnesium salt in water to form an aqueous solution. The salt may be a hydrated salt, such as a monohydrate or heptahydrate. In some embodiments, the process involves dissolving magnesium sulfate heptahydrate in water.

[0119] The silicate solution may be a sodium silicate solution, a potassium silicate solution, or a combination thereof. Typically, a sodium silicate solution is used. The process for preparing the clay nanoparticles and compositions of the present invention may first involve dissolving a silicate in water to form an aqueous solution. In some embodiments, the process involves dissolving sodium silicate in water.

[0120] Any suitable solution can be used as the salt solution containing the cationic component. These include, for example, a carbonate solution, a phosphate solution, a sulfate solution, a nitrate solution, or a combination thereof. Typically, a carbonate solution is used when the cationic component contains sodium, such that a sodium carbonate solution can be used. The process for making the clay nanoparticles and compositions of the present invention can first involve dissolving the cationic component salt in water to form an aqueous solution. In some embodiments, the process of the present invention includes dissolving sodium carbonate to form an aqueous solution.

[0121] Once the solutions are combined, the process of the present invention typically involves heating the combined solution together. Heating is typically continued until a slurry is formed. The weight percent of solids in the slurry relative to the total weight of the slurry is typically about 1 wt% to 15 wt%, typically about 3 wt% to 12 wt%. Sometimes, the weight percent of solids in the slurry relative to the total weight of the slurry is about 3 wt% to about 5 wt%. Sometimes, the weight percent of solids in the slurry relative to the total weight of the slurry is about 8 wt% to about 10 wt%. The combined solution is typically heated to the boiling point of the slurry (i.e., to about 100°C). Heating at this temperature, typically under reflux, is continued for a period of typically about 30 minutes to about 2 hours, typically about 1 hour.

[0122] The process of the present invention may include a further step, including hydrothermal treatment of the slurry. Hydrothermal treatment, as referred to herein, is any treatment that involves heating a composition (in this case, a slurry) in the presence of water. For example, hydrothermal treatment may include autoclaving. Typically, hydrothermal treatment may occur at a temperature of 60 to 500°C. Hydrothermal treatment may occur at high pressure (i.e., above standard atmospheric pressure (about 100,000 Pa)). Hydrothermal treatment at high pressure may be referred to as autoclaving. Thus, the process of the present invention may include an autoclaving step.

[0123] Typically, the hydrothermal treatment step occurs at a temperature of about 100°C to about 300°C, typically about 150°C to about 250°C, and preferably about 180°C to about 220°C. Typically, the hydrothermal treatment step occurs at a pressure of about 30 psi to about 1800 psi, typically about 60 psi to about 600 psi, and preferably about 100 psi to about 400 psi. Typically, the hydrothermal treatment step lasts for about 1 hour to 24 hours, preferably 2 hours to 12 hours, 4 hours to 8 hours, and most preferably about 6 hours.

[0124] The process of the present invention may further comprise a drying step in which the slurry is dried to form a solid. Drying the slurry may be carried out using any suitable method known to those skilled in the art, such as rotoevaporation, oven drying, or vacuum filtration. Preferably, vacuum filtration (e.g., using a Buchner funnel) is used.

[0125] The process may also include washing and redrying the dried product. Any suitable solvent may be used to wash the product. Typically, deionized water is used. Vacuum filtration (e.g., using a Buchner funnel) may be used in this step.

[0126] The washing step is particularly useful for removing soluble salt impurities such as sulfates. BaCl can be added to the filtrate to assess whether all impurities have been removed. If a precipitate forms, further washing is typically required.

[0127] Typically, more than one drying method is used, such as vacuum filtration in combination with oven drying. Oven drying typically occurs at temperatures not far from standard temperature. Typically, oven drying occurs at temperatures from about 40°C to about 80°C, more typically from about 55°C to about 65°C.

[0128] The drying process may last from about 1 hour to 24 hours, typically from about 6 hours to 14 hours.

[0129] The process of the present invention may further comprise the step of grinding the dried product to form a powder. Grinding may occur using any suitable method, such as using a pestle and mortar.

[0130] The process of the present invention may further comprise the step of adding water to the composition to form a gel.

[0131] When water is added to the composition, the composition may be subjected to vigorous stirring, i.e., stirring with a magnetic stirrer at a speed of 300 rpm to 1000 rpm, such as 500 rpm to 800 rpm. Stirring may occur at any temperature, such as 0° C. to 100° C. or 10° C. to 40° C. Typically, stirring occurs at standard atmospheric temperature and pressure (SATP), such as approximately 25° C. and approximately 15 psi.

[0132] In some embodiments, no further steps are required to obtain a gel. In some embodiments of the process, the gel may then optionally be sterilized by autoclaving. Autoclaving typically occurs at about 100°C to about 140°C, such as about 120°C. Autoclaving typically occurs for 10 minutes to 1 hour, such as 30 minutes. Autoclaving typically occurs at 13 psi to 20 psi, such as 15 psi to 20 psi.

[0133] The process of the present invention may further include the step of adding one or more therapeutic or diagnostic agents to the composition. The one or more therapeutic or diagnostic agents may be added to the composition at any step during the process of the present invention. The one or more therapeutic or diagnostic agents may be added to the composition even before the formation of a gel. The one or more therapeutic or diagnostic agents may be added to the composition after it is in the form of a gel, but before administration to a subject. Alternatively, or additionally, the one or more therapeutic or diagnostic agents may be administered to a subject separately from the gel, for example, by administering the one or more therapeutic or diagnostic agents into the gel in vivo at the target site, or by adding the one or more therapeutic or diagnostic agents as a coating to the gel, particularly if the gel itself is coated on the surface of a medical device such as an implant, stent, or balloon. Typically, the one or more therapeutic or diagnostic agents are added to the composition after it is in the form of a gel, but before administration to a subject. [Example]

[0134] Example 1 - Synthesis of clay nanoparticles 2.65 g of LiSO4.H2O was dissolved in 170 mL of deionized water at room temperature using a stirrer. Once the LiSO4.H2O was dissolved, 56.10 g of MgSO4.7H2O was added. The mixed salt solution was then transferred to a round-bottom flask (RBF) in a modular reactor, which was heated to 60±10°C.

[0135] 21.95 g of Na2CO3 was dissolved in 130 mL of DI water in a separate container at room temperature and under stirring.

[0136] When the RBF contents reached 60°C (±10°C), the Na2CO3 solution was added at approximately 1 drop per second using a stoppered, self-equilibrating addition funnel.

[0137] Then, using a new dropping funnel, 69.7 g of the sodium silicate solution was added to the RBF at approximately 1 drop per second.

[0138] A reflux condenser was then attached to the reactor and the temperature of the reactor was increased to 100° C. The mixed salt solution was then boiled under reflux at atmospheric pressure for 1 hour.

[0139] After 1 hour, while keeping all other conditions unchanged, the reaction mixture was then cooled to 60° C. A resulting slurry was formed.

[0140] The oven was preheated to 200°C with the fan set to maximum and the damper set to 40%.

[0141] The slurry was transferred to autoclave vessels (120 mL per vessel). The autoclave vessels were then placed in an oven for hydrothermal treatment (HT) at 200° C. for 6 hours. The oven was then turned off and the vessels were allowed to cool.

[0142] Once cooled, the slurry was rinsed from the autoclave vessels. The contents of each autoclave vessel were then individually transferred to a Buchner funnel and the filter cake was washed with deionized water. 400 mL of deionized water was used per autoclave vessel.

[0143] The Buchner flask was periodically emptied and the filtrate was tested with BaCl2 solution. If a precipitate formed, it indicated that sulfate was still being washed from the filter cake. Further washing was continued until no more precipitate formed.

[0144] The filter cake was then transferred to a container suitable for the drying procedure. The filter cake was then allowed to dry for at least 8-12 hours and could be left for up to 72 hours. Drying occurred in an oven set at 60°C, 100% fan, and 40% damper.

[0145] The dried filter cake was then ground into a powder using a mortar and pestle for about 10 minutes to obtain fine particles.

[0146] Example 2 - Chemical Composition of Clay Nanoparticles The composition of the clay nanoparticles prepared using the method of Example 1 was then analyzed by elemental analysis using inductively coupled plasma optical emission spectroscopy (ICP-OES). Laponite™ XLG was also assessed using the same method. The results are summarized in Table 1 below, with empirically determined Mg, Li, and Na in the following formula ratios (Na + ) a [(Si8Mg b Li c )O 20 (OH)4] -a The results are presented in Table 1 below:

[0147] [Table 1]

[0148] A comparison of the elemental ratios between Laponite™ and the compositions (collectively referred to as Renovite) specified in Table 1 is also presented graphically in FIG.

[0149] To illustrate further variations in the elemental composition of the nanoclays of the present invention, the method of Example 1 was repeated using variations in the synthesis protocol specified below in Table 2. For each modified synthesis, ICP-OES analytical data for the resulting nanoclays is provided, and the elemental ratios for Mg / Si and Mg / Li compared to Laponite™ are presented in Figure 2.

[0150] [Table 2]

[0151] Example 3 - Protocol for producing a gel The gels of the present invention were prepared as a weight percentage (wt.%) of nanoclay / water, where 1% corresponds to 1 g / 100 ml or 10 mg / ml. Gels were prepared using the nanoclay of the present invention at concentrations ranging from 2 to 7 wt. %. For comparison purposes, reference gels were also prepared using a corresponding amount of Laponite™ as nanoclay. The mixing procedure was designed to ensure complete wetting and dispersion of the clay particles.

[0152] 1) Deionized water (18.2 MΩ, pH 7) is added to a glass bottle with a magnetic stir bar and placed on the stirrer to create a steady vortex that extends near the bottom of the bottle but without exposing the stirrer to air.

[0153] 2) Gradually add the powdered nanoclay into the vortex over a period of 5-10 seconds.

[0154] 3) Allow the suspension to stir at room temperature for 1-2 minutes, then vortex briefly to remove any powder that has stuck to the sides or formed clumps. Stirring is continued for an additional 25 minutes until the colloidal solution is clear.

[0155] 4) The total weight of the bottle containing the gel is measured and then autoclaved for approximately 30 minutes at 121°C and 15 psi using a tabletop autoclave suitable for liquid sterilization. Once it cools, the bottle is reweighed and any lost water is replaced, followed by vortex mixing. To keep the gel of the present invention sterile, handling is under sterile conditions and sterile deionized water is used to replace lost water.

[0156] Example 4 - Rheometric measurements and gelation response to serum The rheological properties of the gels of the present invention were characterized both in their native state and after addition to a bath of simulated serum (40 mg / ml bovine serum albumin in phosphate buffered saline, pH 7.4) to assess their response in physiological solutions (e.g., after injection into the body).

[0157] All rheological measurements were performed on an MCR 92 rheometer (Anton Paar, UK) using a 12 mm parallel plate geometry (PP12 probe), with 117 μl of gel suspension loaded onto the rheometer plates pre-set at 25°C with a 1 mm difference. Isothermal measurements over time for storage and loss moduli in response to serum were performed at a constant oscillatory strain of 0.005% and a 1 rad s -1 The test was performed for 60 minutes at an angular frequency of 100 Hz. After 5 minutes, a serum reservoir was applied to the level of the lower surface of the upper plate. Figure 3 shows that the observed increase in storage modulus in response to serum addition was enhanced in the gels of the present invention compared to Laponite™ gels with corresponding nanoclay concentrations.

[0158] An amplitude sweep covering the range of 0.01 to 100% strain was applied to measure the storage and loss moduli within the linear viscoelastic region (LVR), again at 1 rad s -1 The yield strain and yield stress were defined at a constant angular frequency of . To calculate the yield stress and strain, the elastic stress (τ) was plotted against the shear strain (γ), and the yield stress and strain for each treatment were calculated as the inflection point (>5%) from the linear dependence of τ on γ. Figure 4 shows that in its native state, the gels of the present invention can possess equivalent gel strength (yield stress (Pa)), stiffness (storage modulus (G')), and viscosity (storage modulus (G'')) to Laponite™ gels with corresponding nanoclay concentrations ( Figure 4a , top), but in simulated serum, the increase in gel strength, stiffness, and viscosity was significantly enhanced in the gels of the present invention ( Figure 4b , bottom). FIG. 5 reports the storage and loss moduli for various high and low Li / Mg gels of the present invention and their analogs versus Laponite™ suspensions in simulated serum, showing a significant positive correlation with Mg / Si molar ratio (a) and a significant negative correlation with Li / Si molar ratio (b) across the various nanoclays.

[0159] Example 5 - Protocol for measuring zeta potential half-maximum (PHM) and gelation response to pH The gels of the present invention prepared according to Example 3 were measured to assess the zeta potential dynamics in response to pH. Zeta potential is the electrical potential at a sliding surface. This surface is the interface separating the moving fluid from the fluid that remains attached to the surface. Zeta potential describes the electrokinetic potential in a colloidal dispersion and is a function of the specific surface chemistry of the dispersion, which is affected by changes in pH, salt, and surfactant concentration. At its minimum zeta potential (i.e., its absolute lowest value), the colloid is in its most stable state as a dispersion due to the dominance of repulsive interactions over attractive interactions between particles. As the zeta potential approaches the isoelectric point, attractive interactions increase, leading to particle aggregation.

[0160] Titrations with 1 M HCl (30 ul at 20 second intervals) were performed with a Stabinotem II kit, allowing dynamic measurement of zeta potential (P) with decreasing pH. All titrations were performed on 1 wt.% solutions of clay in filtered ultrapure water, prepared on the day of testing.

[0161] Figure 6 shows the rapid decrease in negative zeta potential (ZP) occurring between pH 8 and pH 5 over the course of titration with HCl. This was a characteristic feature of all nanoclays tested and occurred with increasing particle (aggregate) size, indicating a transition in particle interactions from repulsive to attractive. At high nanoclay concentrations (>2 wt%), the increase in attractive interactions produces gels. The pH at which this rapid decrease in potential occurred coincided with the zeta potential half-maximum (PHM), defined as the point at which the negative ZP is 50% of its mV recorded before the addition of the titrant. Figure 7 shows the pH at which PHM occurs for gels of the present invention (pH PHM ) averages out to 7.33, which is close to physiological pH. This is in contrast to the much lower average pH of 5.9. PHM Figure 8 shows the physiologically optimized pH of the gel of the present invention as well as the improved rheological response to serum. PHMcorrelates with its higher Mg and lower Li content compared to Laponite™ and other high Li analogues of the gels of the present invention.

Claims

1. 1. A composition comprising a plurality of clay nanoparticles, each clay nanoparticle comprising an anionic component and a cationic component, the anionic component having the formula (I): [(Si ８ MM ｂ Li ｃ )O ２０ (OH) ４ ] (I) wherein 5.5<b≦6; wherein c>0 and b / c>12; composition.

2. 2. The composition of claim 1, wherein 12<b / c≦18, preferably 13<b / c≦18.

3. 3. The composition of claim 1, wherein 0.2≦c≦0.

5.

4. The cationic component is Na ＋ The composition of any one of claims 1 to 3, comprising:

5. The composition of any one of claims 1 to 4, further comprising one or more therapeutic or diagnostic agents.

6. 6. The composition of claim 5, wherein the one or more therapeutic or diagnostic agents are therapeutic or diagnostic agents suitable for use in regenerative medicine.

7. 7. The composition of claim 5 or claim 6, wherein the one or more therapeutic or diagnostic agents are selected from small molecules, growth factors, antibodies, biological tissue substitutes, synthetic bone grafts, antimicrobial agents, antibiotics, and cells.

8. The composition of any one of claims 1 to 7, wherein the composition comprises BMP-2.

9. The composition according to any one of claims 1 to 8, wherein the composition is in the form of a gel or a film.

10. 10. The composition of claim 9, wherein the gel exhibits a 50% change in zeta potential within the pH range of pH 6.5 to pH 8 when the zeta potential is measured using acid titration.

11. 11. A kit comprising a syringe or vial, said syringe or vial containing the composition of claim 9 or claim 10.

12. 11. A process for making the composition of any one of claims 1 to 10, said process comprising combining a lithium salt solution, a magnesium salt solution, a solution containing a cationic component, and a silicate solution, and heating the solutions together until a slurry is formed; Optionally, subjecting the slurry to a hydrothermal treatment; Optionally, drying the slurry to form a solid; and Optionally, grinding the solid to form a powder. A process that includes.

13. 13. The process of claim 12, wherein the process further comprises adding water to the composition to form a gel.

14. 11. A composition according to any one of claims 1 to 10 for use in a method of regenerative medicine, a method of tissue repair or regeneration, a method of cell delivery, or for use in the treatment or prevention of infectious diseases.

15. 11. The composition of any one of claims 1 to 10, for use in a method of delivery of one or more therapeutic or diagnostic agents to a target site in the human or animal body, said method comprising administering said composition to said human or animal body, said composition comprising one or more therapeutic or diagnostic agents and / or one or more therapeutic or diagnostic agents are administered separately to said composition in vivo at said target site.

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