NON-STICK ANTIBIOTIC GELS

Abstract

A method of producing a pharmaceutical gel emulsion, wherein the emulsion is an oil-in-water gel emulsion, comprising the steps of forming an oil-in-water emulsion comprising at least one pharmaceutically acceptable oil, at least one aqueous phase, at least one osmotic agent, at least one emulsifying agent, mixing a gelling polysaccharide with the oil-in-water emulsion and allowing the resulting mixture to form the pharmaceutical gel emulsion, optionally mixing an bioactive agent into the pharmaceutical gel emulsion.

Claims

1. A method of producing a pharmaceutical gel emulsion, wherein the emulsion is an oil-in-water gel emulsion, comprising the steps of forming an oil-in-water emulsion comprising at least one pharmaceutically acceptable oil, at least one aqueous phase, at least one osmotic agent, at least one emulsifying agent, mixing a gelling polysaccharide with the oil-in-water emulsion and allowing the resulting mixture to form the pharmaceutical oil-in-water gel emulsion, optionally mixing an bioactive agent into the oil-in-water pharmaceutical gel emulsion.

2. The method of producing a pharmaceutical gel emulsion according to claim 1, comprising the steps of a. forming a first dispersion by dispersing at least one emulsifying agent in an aqueous phase, b. forming an oil-in-water emulsion by dispersing at least one pharmaceutically acceptable oil and at least one osmotic agent in the first dispersion, c. mixing a gelling polysaccharide with the oil-in-water emulsion and allowing the resulting mixture to form the pharmaceutical gel emulsion, d. optionally mixing a bioactive agent such as an antibacterial agent into the pharmaceutical gel emulsion.

3. The method of producing a pharmaceutical gel emulsion according to claim 1, wherein the emulsion is an oil-in-water gel emulsion, comprising the steps of a. forming a first dispersion by dispersing at least one emulsifying agent in at least one pharmaceutically acceptable oil, b. forming an oil-in-water emulsion by dispersing at least one aqueous phase and at least one osmotic agent in the first dispersion, c. mixing a gelling polysaccharide with the oil-in-water emulsion and allowing the resulting mixture to form the pharmaceutical gel emulsion, d. optionally mixing bioactive agent such as an antibacterial agent into the pharmaceutical gel emulsion.

4. The method of producing a pharmaceutical gel emulsion according to claim 1, wherein the pharmaceutical gel emulsion is foamed.

5. The method of producing a pharmaceutical gel emulsion according to claim 1, wherein the pharmaceutical gel emulsion is free of a cross-linking agent capable of cross-linking the gelling polysaccharide.

6. The method of producing a pharmaceutical gel emulsion according to claim 1, wherein the pharmaceutically acceptable oil is comprised in the pharmaceutical gel emulsion in an amount of 2 to 20 weight % based on the total weight of the pharmaceutical gel emulsion.

7. The method of producing a pharmaceutical gel emulsion according to claim 1, wherein the pharmaceutically acceptable oil is a plant oil comprising castor oil or soybean oil.

8. The method of producing a pharmaceutical gel emulsion according to claim 1, wherein the emulsifying agent is chosen among phospholipids such as phosphatidyl choline.

9. The method of producing a pharmaceutical gel emulsion according to claim 1, wherein the emulsifying agent is comprised in the pharmaceutical gel emulsion in an amount of 0.1 to 2.5 weight % based on the total weight of the pharmaceutical gel emulsion.

10. The method of producing a pharmaceutical gel emulsion according to claim 1, wherein the gelling polysaccharide is alginate, agarose, or starch; or carboxymethly cellulose, hydroxypropyl cellulose, or methyl cellulose; or hyaluronic acid, or chitosan.

11. The method of producing a pharmaceutical gel emulsion according to claim 1, wherein the gelling polysaccharide is comprised in the pharmaceutical gel emulsion in an amount of 2 to 5 weight % based on the total weight of the pharmaceutical gel emulsion and/or has a molecular weight of about 400 to 800 kDa.

12. The method of producing a pharmaceutical gel emulsion according to claim 1, wherein the gelling polysaccharide is thermally treated carboxymethly cellulose.

13. The method of producing a pharmaceutical gel emulsion according to claim 1, wherein the osmotic agent is a polyol, and is comprised in the pharmaceutical gel emulsion in an amount of 1 to 3 weight % based on the total weight of the pharmaceutical gel emulsion.

14. The method of producing a pharmaceutical gel emulsion according to claim 1, wherein the osmotic agent is a polyol, preferably a glycerol such as polyethylene glycerol or polypropylene glycerol.

15. The method of producing a pharmaceutical gel emulsion according to claim 1, wherein the at least one aqueous phase is chosen among water, phosphate buffered saline or saline.

16. The method of producing a pharmaceutical gel emulsion according to claim 1, wherein the first dispersion and/or the oil-in-water emulsion are formed via microfluidization, microfiltration or sonication.

17. The method of producing a pharmaceutical gel emulsion according to claim 1, wherein the bioactive agent is an antibiotic such as gentamycin and/or vancomycin.

18. A pharmaceutical gel emulsion obtained by a method according to claim 1.

19. A pharmaceutical gel emulsion, obtained by a method according to claim 1, having a shear storage modulus (G′) above its shear loss modulus (G″), i.e. G′>G″, when measured with a rheometer with a strain sweep at amplitude within the linear viscoelastic range, wherein the emulsion is an oil-in-water emulsion.

20. A pharmaceutical gel emulsion, obtained by a method according to claim 1, having an adhesive failure energy of from 0.1 to 1 N/m, when measured with an AntonPaar rheometer with P2 geometry executing a wet tack test, wherein the emulsion is an oil-in-water emulsion, wherein the emulsion is an oil-in-water emulsion.

21. A pharmaceutical gel emulsion, obtained by a method according to claim 1, wherein the emulsion is an oil-in-water emulsion and the pharmaceutical gel emulsion comprises at least lecithin in an amount of from 1 to 1.5 wt %, a vegetable oil in an amount of 8 to 12 wt %, a glycerol in an amount of 1.75 to 2.5 wt % and a cellulose ether in an amount of from 2.5 to 4.5 wt %, and an aqueous solution.

22. The pharmaceutical gel emulsion, obtained by a method according to claim 1, wherein the emulsion is an oil-in-water emulsion and the pharmaceutical gel emulsion comprises at least lecithin in an amount of about 1 wt %, a castor oil, soybean oil or a mixture of both an amount of about 10 wt %, a polyethylene glycol in an amount of about 2.25 wt % and carboxymethyl cellulose in an amount of from 3 to 4 wt %, and an aqueous solution.

23. The pharmaceutical gel emulsion, obtained by a method according to claim 1, wherein the emulsion is an oil-in-water emulsion and the pharmaceutical gel emulsion comprises at least lecithin in an amount of 1 wt %, a castor oil, soybean oil or a mixture of both an amount of 10 wt %, a polyethylene glycol in an amount of 2.25 wt % and carboxymethyl cellulose in an amount of from 3 to 4 wt %, and phosphate buffer saline in an amount sufficient to bring the total of amounts to 100 wt %.

24. A method of treatment of an infection in the context of a bone fracture, orthopaedic condition, osteosynthesis, and/or joint replacement or preservation, comprising the step of administering a pharmaceutical gel emulsion, obtained by a method according to claim 1.

25. A method of prevention of an infection in the context of a bone fracture, orthopaedic condition, osteosynthesis, and/or joint replacement or preservation, comprising the step of administering a pharmaceutical gel emulsion, obtained by a method according to claim 1.

26. The method of producing a pharmaceutical gel emulsion according to claim 1, wherein the pharmaceutically acceptable oil is comprised in the pharmaceutical gel emulsion in an amount of 2 to 10 weight % based on the total weight of the pharmaceutical gel emulsion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Preferred embodiments of the invention are described in the following with reference to the drawings, which are for the purpose of illustrating the present preferred embodiments of the invention and not for the purpose of limiting the same. In the drawings,

[0080] FIG. 1 shows storage modulus (G′) as a function of strain for composition 1 (line), a grafted hyaluronic acid derivative (cross), CMC (circle), TT-CMC (square).

[0081] FIG. 2 shows a typical force-displacement curve, i.e. normal force as a function of gap width, obtained for composition 1 (cross) and a solution of CMC having the same concentration as composition 1 in terms of CMC (circle).

[0082] FIG. 3 shows results of the adhesion energy for the tack test of composition 1 in comparison to a solution of CMC having the same concentration as composition 1 in terms of CMC. The reduction in adhesion energy is evident.

[0083] FIG. 4 shows the extrusion of a gel emulsion according to the present invention from a syringe into a physiological solution, illustrating the capacity of staying cohesive in water environment.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0084] The gel emulsion according to the present invention may also be suitable for use in the treatment of internal or external body trauma, in orthopedic surgery, in joint arthroplasty, in a drug delivery system, in an antibiotic delivery system or other anti-infective delivery systems (including but not limited to additives such as, disinfectants, antimicrobial peptides, quorum sensing inhibitors to prevent biofilm formation, silver (in any pharmaceutical form), nanoparticulates, anti-bacterial adhesins to prevent bacterial attachment, anti MSCRAMMs (microbial surface components recognizing adhesive matrix molecules)) or in the treatment of bone or cartilage defects.

EXAMPLES

[0085] Samples were prepared to demonstrate the rheological properties of several embodiments of the gel emulsions according to the present invention and the tackiness was determined according to a tack test.

Example 1

[0086] Preparation of Composition 1:

TABLE-US-00001 Soybean Soybean Water for Lecithin Oil injection Glycerol CMC total Composition 1 0.48 g 4 g 33.02 g 0.9 g 1.6 g 40 g % 1.2% 10.0% 82.55% 2.25% 4.0%

[0087] Procedure:

[0088] The soybean lecithin is dispersed in the water phase and sonicated with an immersion probe ultrasound generator until the dispersion is homogeneous, typically by applying 2 minutes of ultrasound at full power and 50% cycle. The other liquid components (oil and glycerol) are added, and sonication is applied under the same conditions until a homogeneous dispersion is obtained. Carboxymethyl cellulose (CMC) having a molecular weight of 700 kDa is added, and mixed into the dispersion for 3 minutes, allowed to rest for one hour; the cycle of mixing and rest is repeated at least 3 times. The mixture is allowed to rest for 24 h, and finally steam sterilized with a cycle for liquid substances.

Example 2

[0089] Preparation of Composition 2:

TABLE-US-00002 Soybean Water for TT- Designation Lecithin Oil injection Glycerol CMC total Composition 0.48 g 4 g 33.42 g 0.9 g 1.2 g 40 g 1 % 1.2% 10.0% 83.55% 2.25% 3.0%

[0090] Procedure:

[0091] The lecithin is dispersed in the water phase and sonicated with an immersion probe ultrasound generator for 2 minutes at full power and 100% cycle to obtain a homogeneous dispersion. The other liquid components (oil and glycerol) are added, and sonication is applied under the same conditions until a homogeneous dispersion is obtained. The TT-CMC is added, and manually mixed into the dispersion for 3 minutes, allowed to rest for one hour; the cycle of mixing and rest is repeated 3 times. The mixture is allowed to rest for 24 h, and finally steam sterilized with a cycle for liquid substances. Under sterile conditions, the composition is added to Gentamicin Sulfate and Vancomicin to obtain a final concentration of 1% Gentamicin Sulfate and 4% Vancomicin.

[0092] The thermally treated CMC (TT-CMC) is obtained by introducing the CMC on a glass vessel, reducing the pressure vacuum and raising the temperature to 110° C. and maintaining said conditions for 24 h to yield thermally treated CMC (TT-CMC).

[0093] Compound 1 was characterized in terms of rheology, tested for tackiness and compared with other viscoelastic substances used for antibiotic and drug delivery. The measurements are shown in FIGS. 1, 2, 3 and 4.

[0094] In FIG. 1, an amplitude sweep test measuring the storage modulus (G′) at 1 rad/sec for a strain varying from 0.01% until 100% was carried out on several samples. As can be seen from FIG. 1, within the linear viscoelastic range, composition 1 (line) has a decrease of G′ of about 7% compared to a standard solution of CMC of the same concentration. A known thermoresponsive hyaluronic acid hydrogel (HpN) obtained as detailed in the paper: M D′Este, M Alini, D Eglin, Carbohydrate polymers 90 (3), 1378-1385 and dissolved 10% w/v was used as a reference in terms of viscoelastic behavior (cross), since it is known to possess a suitable rheological behavior for the application considered in the context of the present invention. Specifically, HpN was used for antibiotic delivery with proven preclinical success. FIG. 1 further shows that while rheological properties of HpN cannot fully be matched by using CMC in 4% in PBS, a match can be achieved using TT-CMC in 4% in PBS.

[0095] In FIG. 2, the execution of a tack test is reported, where a track of the force as a function of the path is obtained. From the integration of these curves, the adhesive failure energy can be calculated; the adhesion energy so obtained is illustrated in FIG. 3.

[0096] In FIG. 3, composition 1 was compared to CMC in a tack test, which measures the adhesive failure energy. The test was performed with an AntonPaar MCR302 rheometer according to the pre-defined protocol, where the substance to be analyzed is inserted in the gap, allowed to equilibrate and finally the plate is pulled up at controlled displacement while measuring the normal force. FIG. 3 shows the results of the tack test for composition 1 in comparison to CMC in 4% PBS. Each substance was tested in triplicate N=3 and the results are shown as box plot. The adhesive failure energy (as calculated by the measurement software by integration of the force/displacement curve) of the CMC in 4% PBS is about 3 times higher than that of the adhesion energy in composition 1. Even though the composition 1 sample comprises the same amount of CMC than the CMC in 4% PBS sample and displays similar viscoelastic properties (see FIG. 1) the adhesion force is significantly lower. This result is very surprising because typically adhesion force is related to viscoelastic properties, i.e. the higher the viscoelastic properties as measured in rheological tests with G′ the higher the adhesion force.

[0097] In summary, the compositions of the present invention will stay where placed by the surgeon (owing to the high storage modulus (G′)) and at the same time not stick to the surgeon gloves (owing to the low adhesion force), thereby overcoming a universally recognized limitation of existing antibiotic-loaded biomaterials and/or gels.

Example 3

[0098] Preparation of Composition 3:

TABLE-US-00003 Sodium Soybean Water for Lecithin oleate B Oil injection Glycerol CMC total Compo- 0.48 g 12 mg 3 g 34.01 g 0.9 g 1.6 g 40 g sition 1 % 1.2% 0.003% 10.0% 82.55% 2.25% 4.0%

[0099] Egg lecithin with 70-80% phosphatidylcholine is mixed with sodium oleate B in proportion 40:1 and dispersed in the soybean oil until the dispersion is homogeneous, and no clumps are present. Water is combined with glycerol, mixed to homogeneity, combined with the dispersion of phosphatidyl choline and oleate in soybean oil and treated with a high-shear mixer in a temperature range between 25 and 50° C. until a homogeneous and stable dispersion is obtained. The obtained dispersion is steam sterilized for 20 minutes at 121° C. This sterile liquid composition was then delivered to the operating theater, and mixed under sterile conditions with 1.6 g of sterile CMC having a molecular weight of about 500 kDa, daptomycin and gentamicin sulfate to obtain a final concentration of 1% Gentamicin Sulfate and 4% daptomycin. The CMC and the antibiotics are thoroughly mixed until a homogeneous paste is obtained.

Example 4

[0100] Preparation of Composition 4:

TABLE-US-00004 Component Soyb CMC A Surfactant Oil Gly-water 0.7 kDa Amount 1143.75 9530 63312.5 2861.25 (mg)

TABLE-US-00005 Water per Gentamicin Solution B injection Vancomycin sulfate Amount (mg) 18575 3656.25 913.75

[0101] Component A is prepared as follows using the quantities reported in the table above. The surfactant is prepared by mixing egg lecithin of high purity (containing egg phospholipids with 80% phosphatidylcholine) with sodium oleate in ratio 40/1 lecithin/oleate. A solution is prepared dissolving injection-grade glycerol 3.42 weight % in water per injection to obtain the Gly-water solution. The surfactant is dispersed in the soybean oil with a turbo-mixer until homogeneity. The obtained dispersion is combined with the Gly-water solution and mixed under high shear until homogeneity. At this point CMC is incorporated in the dispersion and mixed until homogeneity to obtain Component A, which is steam sterilized and stored at 2-8° C. until use.

[0102] Solution B is prepared under sterile conditions by dissolving the indicated amounts of Vancomycin and Gentamicin sulfate in the indicated amount of water per injection.

[0103] In order to yield the gel emulsion Composition 4 according to the present invention ready for application at the site of interest, a syringe containing viscoelastic dispersion A is combined with a syringe containing solution B and mixed until homogeneity by means of transferring the solution from one barrel to the other for 30 times to obtain an homogeneous viscoelastic dispersion ready for injection.

Example 5: Cohesion Test of the Composition 4 Prepared in Example 4

[0104] A syringe containing 10 ml of the gel emulsion prepared as per example 4 is prepared. The gel emulsion is extruded through the orifice of the syringe into a water bath at physiological osmolarity at 37° C. As can be seen, the extruded gel emulsion preserves its shape after leaving the syringe, before and after entering a physiological environment, demonstrating the suitability of the gel emulsion of example 4 to be used for injection in the human body and avoiding washing-out from body fluids and displacements from compression by adjacent tissues.

Example 6: Composition for Intraoperative Mixing with Antibiotics

[0105] The same procedure of example 4 is followed, with the only difference of using castor oil instead of soybean oil

Example 7: Composition for Intraoperative Mixing with Antibiotics

[0106] The same procedure of example 4 is followed, with the only difference of employing ultrasound and microfiltration instead of high-shear mixing to obtain the emulsion.

Example 8: Composition for Intraoperative Mixing with Antibiotics

[0107] The same procedure of example 4 is followed, with the only difference of employing purified soy lecithin instead of a combination of egg lecithin and sodium oleate as emulsifier.

Example 9: Composition for Intraoperative Mixing with Antibiotics

[0108] The same procedure of example 4 is followed, with the only difference performing the preparation of the Component A setting the temperature between 40 and 55° C.

Example 10: Composition for Intraoperative Mixing with Antibiotics

[0109] The same procedure of example 4 is followed, with the only difference performing the preparation of the Component A setting the temperature between 5 and 25° C.

Example 11: Composition for Intraoperative Mixing with Antibiotics

[0110] The same procedure of example 4 is followed, with the only difference performing the preparation of the Component A setting the temperature between 25 and 40° C.

Example 12: Preparation of a Foam for Antibiotics Delivery

[0111] The same procedure of example 4 is followed, with the difference that a final concentration of CMC of 1.5% is achieved. The antibiotic-loaded composition is mixed under high-shear incorporating nitrous oxide, and packaged into pressure-tight cylinders to provide a ready-to-use foaming agent.

Example 13: Composition for Intraoperative Mixing with Antibiotics

[0112] The same procedure of example 4 is followed using CMC of molecular weight 700 kDa

Example 14: Composition for Intraoperative Mixing with Antibiotics

[0113] The same procedure of example 4 is followed using CMC of molecular weight 100 kDa.

Example 15: Composition for Intraoperative Mixing with Antibiotics

[0114] The same procedure of example 4 is followed, with the only difference of using purified medical grade olive oil instead of soybean oil.

Example 16: Composition for Intraoperative Mixing with Antibiotics

[0115] The same procedure of example 4 is followed, with the only difference of replacing gentamicin sulfate and vancomycin with rifampicin for a final rifampicin concentration in the final formulation of 4%.