Abstract:
An inflatable balloon of an intragastric device comprises a substantially homogonous lend of polydiphenylsiloxane and polydimethylsiloxane. The substantially homogenous blend improves elongation percentage, tear strength, permeability, and modulus as compared to its constituent parts taken alone.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/390,996, filed Oct. 7, 2010, entitled “MATERIALS AND METHODS FOR IMPROVED INTRAGASTRIC BALLOON DEVICES,” which is incorporated herein by reference in its entirety. 
         [0002]    This application also incorporates herein by reference the following patent publications and applications in their entireties: U.S. Patent Publication No. 2007/0100367, published May 3, 2007; U.S. Patent Publication No. 2007/0100368, published May 3, 2007; U.S. Patent Publication No. 2007/0100369, published May 3, 2007; U.S. Patent Publication No. 2007/0149994, published Jun. 28, 2007; U.S. Patent Publication No. 2008/0243071, published Oct. 2, 2008; U.S. Patent Publication No. 2008/0319471, published Dec. 25, 2008; U.S. Patent Publication No. 2005/0159769, published Jul. 21, 2005; U.S. Patent Publication No. 2009/0048624, published Feb. 19, 2009; WIPO Publication No. WO 2007/053556, published Oct. 5, 2007; WIPO Publication No. WO 2007/053707, published Oct. 5, 2007; WIPO Publication No. WO 2007/053706, published Oct. 5, 2007; and WIPO Publication No. WO 2007/075810, published May 7, 2007. 
     
    
     TECHNICAL FIELD 
       [0003]    This disclosure relates to implantable, expandable gastric devices. In particular, this disclosure relates to improved structures of balloons and methods of producing the same. 
       SUMMARY 
       [0004]    An intragastric device, comprising, in combination: a molded inflatable balloon, comprising a substantially homogonous blend of polydiphenylsiloxane and polydimethylsiloxane material. 
         [0005]    An amount of the polydimethylsiloxane of the inflatable balloon may exceed an amount of the polydiphenylsiloxane of the inflatable balloon, by weight. The polydiphenylsiloxane may be about 15% of the inflatable balloon, by weight. The inflatable balloon may be mostly of the polydimethylsiloxane, by weight. 
         [0006]    The inflatable balloon further may comprise a therapeutically active material. The therapeutically active material may be an anti-microbial additive. 
         [0007]    The substantially homogonous blend may be of a greater elongation percentage than the polydiphenylsiloxane alone. The substantially homogonous blend may have a greater tear strength than the polydiphenylsiloxane alone or the polydimethylsiloxane alone. The substantially homogonous blend may have a lower permeability than the polydimethylsiloxane or a combination blend with polydiphenylsiloxane material. The substantially homogonous blend may have a greater modulus than the polydimethylsiloxane alone. 
         [0008]    The intragastric device may further comprise a shaft. The inflatable balloon may further comprise two cuffs configured to receive the shaft extended through the inflatable balloon. 
         [0009]    A method of producing an inflatable balloon, comprising, in combination: providing a mold and mandrel; providing a substantially homogonous blend of polydiphenylsiloxane and polydimethylsiloxane material within the mold and around the mandrel, whereby the balloon is defined by the space between the mold and the mandrel, the balloon having a cuff at an end thereof and a middle diameter corresponding to a middle diameter of the mandrel; removing the mold from about the balloon and the mandrel from within the balloon through the cuff. 
         [0010]    The middle diameter of the mandrel may be between about 400% and about 600% larger than a diameter of the cuff. The expansion capabilities of the substantially homogonous blend may facilitate expansion of the cuff to allow exit of the mandrel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed on illustrating clearly the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0012]      FIG. 1  shows a perspective view of a balloon; 
           [0013]      FIG. 2  shows a perspective view of an intragastric device; 
           [0014]      FIG. 3  shows a side view of an intragastric device; 
           [0015]      FIG. 4  shows a top view of an intragastric device; 
           [0016]      FIG. 5  shows a sectional view of a balloon with a magnified view; 
           [0017]      FIG. 6  shows a sectional view of a balloon with a magnified view; and 
           [0018]      FIG. 7  shows a sectional view of a balloon with a magnified view. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Specific details of several embodiments of the technology are described below with reference to  FIGS. 1-7 . Although many of the embodiments are described below with respect to devices, systems, and methods associated with intragrastric space fillers, other applications and other embodiments in addition to those described herein are within the scope of the technology. Additionally, several other embodiments of the technology can have different configurations, components, or procedures than those described herein. A person of ordinary skill in the art, therefore, will accordingly understand that the technology can have other embodiments with additional elements, or the technology can have other embodiments without several of the features shown and described below with reference to  FIGS. 1-7 . 
         [0020]    According to embodiments, and as shown in  FIG. 1 , balloon  30  is any expandable, space filling component. Balloon  30  may have any variety of geometries and shapes. As shown in  FIGS. 1 and 3 , balloon  30  may have at least one cuff  40  for interfacing with other components, such as shaft  20  extending through balloon  30 . Balloon  30  may be an open or closed balloon. Balloon  30  may have an inner surface and outer surface. 
         [0021]    According to embodiments, and as shown in  FIG. 2 , at least one balloon  30  may be a component of an intragastric device  10 . As further shown in  FIG. 2 , a plurality of balloons  30  may be joined by a common shaft  20  extended and connecting the plurality of balloons  30 . 
         [0022]    According to embodiments, intragastric device  10  with at least one balloon  30  may be configured for use as an implantable device within a gastric cavity. Where implant is temporary, intragastric device  10  must be explanted after some period of time. Durability and longevity of intragastric device  10  may be defined, at least in part, by characteristics of balloon  30 . Balloon  30  may be subjected to harsh gastric environments for an extended amount of time. Accordingly, the materials and manufacturing methods of the materials are key contributors as to balloon integrity and longevity. 
         [0023]    According to embodiments, balloon  30  may be of at least one silicone-containing material. Two examples of such materials are polydimethylsiloxane (PDMS) and polydiphenylsiloxane (PDPS). PDMS may be represented as [SiO(CH 3 ) 2 ] n  or graphically as follows: 
         [0000]    
       
                 
         
             
             
         
       
     
         [0024]    PDPS may be represented as [SiO(C 6 H 5 ) 2 ] n  or graphically as follows: 
         [0000]    
       
                 
         
             
             
         
       
     
         [0025]    According to embodiments, at least one of PDMS and PDPS may form the base material of at least a portion of balloon  30 . Other materials, structures, or compounds may be mixed or cross-linked with the based material. 
         [0026]    According to embodiments, a plasma etching or coating may be provided to at least a portion of balloon  30 . Plasma etching may involve a high-speed stream of glow discharge (plasma) of an appropriate gas mixture being shot (in pulses) at a sample. The plasma source can be either charged (ions) or neutral (atoms and radicals). During the process, the plasma will generate volatile etch products at room temperature from the chemical reactions between the elements of the material etched and the reactive species generated by the plasma. The atoms of the shot element embed themselves at or just below the surface of the target, thus modifying the physical properties of balloon  30 . Etching may facilitate better adherence between layers of balloon  30 . 
         [0027]    According to embodiments, various coatings (e.g., hydrophilic) may be applied to at least a portion of balloon  30 . For example, a hydrophilic coating may be provided where two surfaces of balloon  30  resist flow of fluid there through. 
         [0028]    The respective chemical structures of PDMS and PDPS confer relatively disparate characteristics, which may be summarized as follows: 
         [0000]    
       
         
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Polydimethylsiloxane 
                 Polydiphenylsiloxane 
               
               
                   
               
             
             
               
                 Manufacturing method: 
                 Molding, extrusion 
                 Dipping 
               
               
                 Curing: 
                 Heat 
                 Heat 
               
               
                 Consistency: 
                 More dimensional  
                 Less dimensional 
               
               
                   
                 (moldable) 
                 (dipping) 
               
               
                 Elasticity: 
                 Higher 
                 Lower 
               
               
                 Tensile Strength: 
                 Lower 
                 Higher 
               
               
                 Acid resistance: 
                 Acceptable 
                 Increased 
               
               
                 Permeability: 
                 Higher 
                 Lower 
               
               
                 Molecular density: 
                 Lower 
                 Higher 
               
               
                 Polymer Chain Length 
                 Standard 
                 Longer 
               
               
                   
               
             
          
         
       
     
         [0029]    In various applications and based on different aspects, each of PDMS and PDPS may be seen as providing certain advantages and disadvantages. 
         [0030]    According to embodiments, the more dimensional consistency and higher elasticity of PDMS materials and PDMS blends provide balloon  30  facilitate molding and extrusion processes. In particular, molding processes involving mandrels are better served by materials with higher elasticity due to the stresses involved in the mandrel removal process. For example, balloon  30  may be defined by a mandrel that has a larger diameter at a central portion than a diameter at one or both ends (corresponding to cuffs  40 ). By further example, a mandrel may have a middle diameter that is up to 600% larger than its end diameters. Balloon  30  results in a corresponding middle diameter and opening through cuff  40 . Balloon  30  must provide enough elasticity to have the mandrel with middle diameter removed through cuff  40  without damaging cuff  40 . As shown in Table 1, PDMS materials generally provides greater elasticity capabilities than PDPS materials. 
         [0031]    According to embodiments, the expansion ratio of balloon  30  from an uninflated state (i.e., before and during implant) to an inflated state (i.e., after implant) may be significant. For example, balloon  30  may have an outer diameter of about 1.9″ in an uninflated state and about 4″ in an inflated state (over 200% expansion). By further example, balloon  30  may have a volume of about 80 cc in an uninflated state and about 450-500 cc in an inflated state (over 600% expansion). These factors are well-served by PDMS materials and PDMS based blends. 
         [0032]    According to embodiments, higher acid resistance, a longer polymer chain (to resist degradation), double bonds (to resist degradation), increased hydrophobicity and less permeability (to reduce ingress/egress of materials) of PDPS materials and PDPS blends would better limit the ingress or egress of materials across the walls of balloon  30  and support longevity of balloon  30 . Generally, PDPS, as compared to PDMS, is less able to provide consistent wall thicknesses and is less capable of generating molding friendly features because PDPS based materials generally are higher consistency in raw form (thicker &amp; dense) and do not pump well in liquid injection molding (LIM) presses. 
         [0033]    According to embodiments, balloon  30  may have a multiple-material composition. A plurality of disparate materials and material blends may be provide in layers forming walls of balloon  30 . For example, a wall of balloon  30  may have a core  50  with at least one coating on an inner or outer surface thereof. 
         [0034]    According to embodiments, and as shown in  FIG. 5 , an outer surface of core  50  may be provided with outer coating  60   a . Outer coating  60   a  may be provided, for example, by a dipping process after core  50  is formed. 
         [0035]    According to embodiments, and as shown in  FIG. 6 , an inner surface of core  50  may have inner coating  60   b . Inner coating  60   b  may be provided, for example, by a dipping process after core  50  is formed. 
         [0036]    According to embodiments, and as shown in  FIG. 7 , an outer surface and an inner surface of core  50  may have outer coating  60   a  and inner coating  60   b . Outer coating  60   a  and inner coating  60   b  may be provided, for example, by a dipping process after core  50  is formed. 
         [0037]    According to embodiments, balloon  30  having layered multiple-material composition may benefit from the advantaged of each material while mitigating or minimizing the detriments of each. 
         [0038]    According to embodiments, a method of making balloon  30  is disclosed. According to embodiments, core  50  may be molded of liquid silicone rubber (LSR) grade material, such as PDMS. Those skilled in the art will recognize various molding and extrusion processes that may facilitate formation of core  50 . According to embodiments, after removal of core  50  from its mold, mandrel, or other devices, core  50  may be dipped in a second substance to form at least one of outer coating  60   a  and inner coating  60   b . Other methods may be employed, such as spraying, coating, washing, etc. 
         [0039]    According to embodiments, core  50  may compose a substantial portion of the total sum of balloon  30  or at least the walls thereof. For example, the thickness of core  50  may be between about 0.001″ and about 1.0″. By further example, the thickness of core  50  may be between about 0.024″ and about 0.030″. Other thicknesses may be applied based on the needs and applications of the desired product. 
         [0040]    According to embodiments, outer coating  60   a  or inner coating  60   b  may be a thin layer, relative to the thickness of core  50 . For example, outer coating  60   a  or inner coating  60   b  may a thickness of about 1% to about 99% of the thickness of core  50 . By further example, outer coating  60   a  or inner coating  60   b  may a thickness of about 10% to about 20% of the thickness of core  50 . Other thicknesses may be applied based on the needs and applications of the desired product. It should be noted that outer coating  60   a  or inner coating  60   b  of PDPS materials increase the stiffness of balloon  30  and reduce elongation properties thereof. 
         [0041]    According to embodiments, balloon  30  having core  50  and at least one of outer coating  60   a  and inner coating  60   b  may have a substantially consistent surface and retain elastic material properties, increased acid resistance, a longer polymer chain (resist degradation), double bonds (resist degradation), increased hydrophobicity and less permeability (reduces ingress/egress of materials). 
         [0042]    According to embodiments, balloon  30  may be of a single blended molding/extrusion grade material. Balloon  30 , or portions thereof, may be a blend of PDPS material(s) and PDMS material(s). According to embodiments, a blended material for balloon  30  comprises PDPS materials and PDMS materials. The blended material may be at least mostly of a PDMS base. The blended material may have a PDPS material compounded in. For example, a blended material may be of between about 50% and about 99% PDMS and between about 50% and about 1% PDPS. 
         [0043]    According to embodiments, PDMS and PDPS material blends can be compounded at the raw material level by a manufacturer. Depending on the consistency (Durometer) and batch size of the material the blends can either be, but not limited to, manual mixed using basic spatulas and beaker, roller mills or any other acceptable proprietary mixing methods. Other proprietary additives may also be compounded in to enable the material to be processed in molding/extrusion fabrication processes. 
         [0044]    According to embodiments, balloon  30  may be loaded with additional materials. For example, active materials for therapeutic use in situ may be provided within the composition of balloon  30 . Said additional materials may be at least substantially homogenously distributed throughout balloon  30 . Other materials considered for blending into the silicone material are salt or silver based anti-microbial additives. Other active materials for providing therapeutic benefits are contemplated by the present disclosure. 
         [0045]    According to embodiments, the blended material is a liquid silicone rubber (LSR) grade material. The material can be injected into a molding press. 
         [0046]    According to embodiments, a PDPS/PDMS blend material reduces processing required to manufacture balloons that are molded and dipped in sequential steps. PDPS/PDMS blends further ensure a substantially homogenous mix of the materials and properties throughout the balloon, unlike a composite of multiple layers generated with a molded and dipped balloon. 
         [0047]    For example, a custom blended material was created by combination of a Di-methyl base material with 15% Di-phenyl material compounded in (“LSR-9958-30”). Separate lots thereof were compared to various lots of “MED-4820 Liquid Injection Molding Silicone Elastomer,” “MED-6400 Addition Cure Silicone Dispersion,” and “MED-6600 Addition Cure Silicone Dispersion,” all by NuSil Technology (Carpinteria, Calif.). The tables below demonstrate features of the materials analyzed. 
         [0000]    
       
         
               
             
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 (Custom Blend) 
               
             
          
           
               
                   
                 LSR-9958-30—Lot 1 
                 LSR-9958-30—Lot 2 
                 Average 
               
               
                   
               
             
          
           
               
                 Specific Gravity 
                 1.21 
                 1.2 
                 1.2 
               
               
                 Durometer (A-Scale) 
                 21 
                 26 
                 24 
               
               
                 Tensile Psi (Min.) 
                 1499 
                 1916 
                 1708 
               
               
                 Elongation % (Min.) 
                 946 
                 998 
                 972 
               
               
                 Tear Strength Ppi (Min.) 
                 286 
                 322 
                 304 
               
               
                 Phenyl Content % 
                 15 
                 15 
                 15 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 (Off the Shelf Di-Methyl Liquid Injection Molding Blend) 
               
             
          
           
               
                   
                 MED-4820—Lot 1 
                 MED-4820—Lot 2 
                 Average 
               
               
                   
               
             
          
           
               
                 Specific Gravity 
                 1.12 
                 1.12 
                 1.1 
               
               
                 Durometer (A-Scale) 
                 23 
                 22 
                 23 
               
               
                 Tensile Psi (Min.) 
                 1254 
                 886 
                 1070 
               
               
                 Elongation % (Min.) 
                 914 
                 897 
                 906 
               
               
                 Tear Strength Ppi  
                 97 
                 116 
                 107 
               
               
                 (Min.) 
                   
                   
                   
               
               
                 Phenyl Content % 
                 0 
                 0 
                 0 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
             
               
               
               
             
           
               
                 TABLE 4 
               
             
             
               
                   
               
               
                 (Off the Shelf Di-Methyl and Di-Phenyl Dinning Blend) 
               
             
          
           
               
                   
                 MED-6400 
                 MED-6600 
               
               
                   
               
             
          
           
               
                 Specific Gravity 
                 1.13 
                 1.17 
               
               
                 Durometer (A-Scale) 
                 30 
                 25 
               
               
                 Tensile Psi (Min.) 
                 1500 
                 1200 
               
               
                 Elongation % (Min.) 
                 775 
                 750 
               
               
                 Tear Strength Ppi (Min.) 
                 150 
                 125 
               
               
                 Phenyl Content % 
                 5 
                 5 
               
               
                   
               
             
          
         
       
     
         [0048]    As shown, the material properties of the LSR-9958-30 are as good as or better than the lots received for MED-4820. In some areas, such as tear strength, the custom blend is magnitudes better than the MED-4820. As shown in Table 1, a typical material property of Di-Phenyl loaded blends is a lower elongation percentage. This material limitation (typically elongation % is around 750%) has been addressed without any sacrifice to tensile properties as shown in Tables 2-4 above. The standard off-the-shelf Di-Phenyl loaded blends (dipping material) contains approximately a 5% loading. Given the material property benefits achieved with the add Di-Phenyl at a 5% loading, the LSR-9958-30 blend benefited greatly from the 15% Di-Phenyl loading particularly in the area of permeability (approximately 30% percent reduction). Another mechanical property that has increased is Young&#39;s Modulus (Tensile Modulus) because tensile psi has increased while elongation has stayed relatively constant from MED-4820 to LSR-9958-30. 
         [0049]    From the foregoing, it will be appreciated that specific embodiments of the present technology have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the disclosure. Aspects of the disclosure described in the context of particular embodiments may be combined or eliminated in other embodiments. Further, while advantages associated with certain embodiments of the disclosure have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the disclosure. Accordingly, embodiments of the disclosure are not limited except as by the appended claims.