Abstract:
A disinfectant cap for sterile liquid dispensers is disclosed. The cap includes a biocide-containing reservoir separated from the hollow interior of the cap by a rigid partition having an aperture therein for receiving the outlet port of the dispensing end of the dispenser, the cap being configured such that when in a closed configuration, the outlet port of the dispensing end extends through the aperture into the biocide-containing reservoir and the rigid partition is configured such that when the cap is removed from the dispensing end the biocide is retained in the reservoir. This may be achieved by selecting the size of the aperture such that when the cap is removed from the dispensing end the biocide is retained in the reservoir by surface tension. Or the partition may be provided with a hinged flap which seals the aperture when the cap is removed from the dispensing end and which is moved away from the aperture when the outlet port extends through the aperture.

Description:
TECHNICAL FIELD 
       [0001]    The invention relates to the field of dispensers for sterile liquids. 
       BACKGROUND 
       [0002]    Various ophthalmic and medical applications require a hand-held dispenser of multiple doses of sterile liquids. Sterile saline is required by contact lens wearers for use as a rinse solution, for rinsing the lens prior to inserting the lens in the eye, and also for soaking the lens during the cleaning and disinfecting process. Dispensers have been designed to maintain such liquids in a sterile state for dispensing, such as disclosed in the present inventor&#39;s U.S. Pat. No. 5,507,417, which discloses a dispenser for sterile saline solution and U.S. Pat. No. 6,745,763 which discloses a vaporizing device for administering sterile medication. Similarly, dispensers of medicinal liquids for eye, ear and nose drops desirably keep such liquids sterile between uses to prevent bacterial growth. An example of such device is disclosed in U.S. Pat. No. 4,533,068 Meierhoefer, wherein a hydrophobic filter is used to sterilize the replacement air which enters the dispenser upon release of the squeezing pressure. Other devices use an anti-bacterial hydrophobic filter over the outlet port, or hydrophobic and hydrophilic filters in tandem, to maintain the liquid sterile. See U.S. Pat. No. 3,149,758 Bush et al.; U.S. Pat. No. 4,938,389 Rossi et al. and Kramer et al. U.S. Pat. No. 4,463,880. 
         [0003]    Commonly such dispensers use a one-way valve or pump with a one-way valve to dispense the sterile liquid from a squeeze bottle or collapsible reservoir. A problem with existing devices is that after the sterile liquid is dispensed, some residue remains on the outlet port, or is drawn back into the outlet conduit, which can become contaminated with bacteria or the like and which will contaminate the next dose of the sterile liquid which is dispensed through the outlet port. There is therefore a need to avoid the foregoing problem with sterile liquid dispensers. 
       SUMMARY OF INVENTION 
       [0004]    The present invention provides a disinfectant cap for sterile liquid dispensers. The invention provides a cap for a dispenser for sterile liquid having a hollow container for storing said sterile liquid and a dispensing end having an outlet port, the cap comprising a closed end and an open end, a hollow interior communicating with the open end and a biocide-containing reservoir separated from the hollow interior by a rigid partition having an aperture therein for receiving the outlet port of the dispensing end, the cap being configured such that when in a closed configuration, the outlet port of the dispensing end extends through the aperture into the biocide-containing reservoir and wherein the rigid partition is configured such that when the cap is removed from the dispensing end the biocide is retained in the reservoir. According to one aspect of the invention, the size of the aperture is selected such that when the cap is removed from the dispensing end the biocide is retained in the reservoir by surface tension. According to another aspect of the invention, the partition is provided with a hinged flap which seals the aperture when the cap is removed from the dispensing end and which is moved away from the aperture when the outlet port extends through the aperture. The invention also provides a sterile liquid dispenser incorporating the foregoing cap. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0005]    In drawings which disclose a preferred embodiment of the invention: 
           [0006]      FIG. 1  is a perspective view of a disinfectant cap according to the invention; 
           [0007]      FIG. 2  is a top view of the disinfectant cap shown in  FIG. 1 ; 
           [0008]      FIG. 3  is a vertical cross section of a first embodiment of the invention taken along line A-A of  FIG. 2 ; 
           [0009]      FIG. 4  is a detail of the section indicated in  FIG. 3 ; 
           [0010]      FIG. 5  is a perspective view of a disinfectant cap in place on a dispenser according to the invention; 
           [0011]      FIG. 6  is a top view of the disinfectant cap and dispenser shown in  FIG. 5 ; 
           [0012]      FIG. 7  is a vertical cross section of the first embodiment of the invention shown in  FIG. 3  taken along line A-A of  FIG. 6 ; 
           [0013]      FIG. 8  is a detail of the section indicated in  FIG. 7 ; 
           [0014]      FIG. 9  is a vertical cross section of a second embodiment of the invention taken along line A-A of  FIG. 6 ; 
           [0015]      FIG. 10  is a vertical cross section of a second embodiment of the invention taken along line A-A of  FIG. 6  and shown in perspective; and 
           [0016]      FIG. 11  is a detail of the section indicated in  FIG. 9 . 
       
    
    
     DESCRIPTION 
       [0017]    Throughout the following description, specific details are set forth in order to provide a more thorough understanding of the invention. However, the invention may be practiced without these particulars. In other instances, well known elements have not been shown or described in detail to avoid unnecessarily obscuring the invention. Accordingly, the specification and drawings are to be regarded in an illustrative, rather than a restrictive, sense. 
         [0018]    With reference to  FIG. 5-8 , a sterile liquid dispenser  10  comprises a hollow, rigid cylindrical container  20  which has hollow interior  11  containing sterile liquid  12  and pressurized gas  13 . Dispenser  10  can be a pressurized dispenser of the type disclosed in the present inventor&#39;s international application number PCT/CA2006/001551 entitled “Pressurized Sterile Liquid Dispenser” which is pending and is incorporated herein by reference. Pressurized dispenser  10  has pressurized storage reservoir  11  for storing the sterile liquid  12 , which is injected into the reservoir through bottom filling valve  15 . Typically the container  20  will be constructed of a rigid molded plastic such as a polycarbonate. The container  20  may have a threads  17  adjacent neck  18  to which a cap  14  may be screwed in place. Alternatively cap  14  may be sized and constructed to provide a friction or snap fit over neck  18  of container  20 . Dispenser  10  has a flexible nozzle  22  which is molded of a rubber such as used in syringes and is molded or welded integrally onto a rigid retainer ring  24  secured by glue or welding to neck  18  of container  20 . Extending upwardly from neck  18  is hollow cylindrical element  25  which surrounds cylindrical chamber  26  and which connects at its upper end to solid conical plug  28 . A cylindrical elastomeric valve  30  is seated against the lower surface of plug  28 , at the upper end of chamber  26 . At rest, valve  30  seals a passage  32  which communicates between chamber  26  and annular chamber  36  between the outer surface of plug  28  and the inner surface of nozzle  22  which extends over plug  28 . A knob  38  can be pressed into contact with the outer surface of valve  30  and to open passage  32  when actuating surface  40  is pressed, thereby forcing knob  38  inwardly against valve  30 . 
         [0019]    In operation, cap  14  is removed from container  20 , which is then inverted. Actuating surface  40  is pressed, thereby opening passage  32 . When passage  32  is opened, liquid under pressure from reservoir  12  is forced through passage  32  into chamber  36  and moves nozzle  22  away from plug  28  to form a liquid droplet at the end of nozzle  22 . The size of passage  32 , chamber  36  and the diameter and flexibility of nozzle  22  are selected so that droplets of liquid  12  of suitable size are formed within the selected time frame. Once the droplet releases, the actuator surface  40  is released. After dispensing the drops, cap  14  is replaced on container  20  with nozzle  22  received in the hollow interior  34  of cap  14 . 
         [0020]    To preserve the sterility of sterile liquid  12  when the liquid is dispensed from nozzle  22 , cap  14  is provided with a quantity of biocide  50  or other disinfectant, such as a gel or liquid, stored in hollow cylindrical chamber  52 . A circular lid  56  is secured by welding or gluing to form the upper wall of chamber  52 . Chamber  52  is separated from the hollow interior  34  of cap  14  by a wall  57  having a central opening  58 . A circular flange  60  extends downwardly from wall  57  around central opening  58 , and has tapered inner surfaces  62  which receives the end of nozzle  22  and allows only the tip of nozzle  22  to extend into chamber  52 , as illustrated in  FIG. 8 . The size of central opening  58  and the relative configurations of the nozzle  22  and surface  62  flange  60  are such that when the cap  14  is replaced on container  20 , the end of nozzle  22  can extend through opening  58  into chamber  52  but the sides of nozzle  22  tightly seal against surfaces  62 , as shown in  FIG. 8 . As illustrated in  FIG. 4 , central opening  58  is sealed by a flexible hinged flap  64  when cap  14  is removed from the container  20 . Flap  64  is made of a resilient rubber material or the like and forms a one-way valve sealing central opening  58 . One end  66  of flap  64  is secured to the upper surface of wall  57  while the opposite end  68  of flap  64  is free to be raised upwardly into chamber  52  when contacted by nozzle  22 . 
         [0021]    Chamber  52  is partially filled with biocide  50  prior to use using a needle or other injector inserted through opening  58 . Some air space is left in chamber  52  so that flap  64  can open when the nozzle  52  is inserted into opening  58 . 
         [0022]    When cap  14  is replaced over the dispensing nozzle  22 , as shown in  FIG. 8 , the end of nozzle  22  extends through central opening  58  and is immersed in the biocide  50 , thereby placing biocide in contact with the surface of the tip of nozzle  22 . The end of nozzle  22  is thus sterilized during storage and prior to each dispensing of liquid. When cap  14  is removed from container  20 , nozzle  22  is withdrawn from the central opening  58 . As the tip of nozzle  22  is drawn downwardly in opening  58 , the resiliency and flexibility of flap  64  is such that it slides across the face of the tip of nozzle  22  with a wiping or squeegee action, thereby wiping substantially all biocide from the tip of nozzle  22  as it is withdrawn and preventing any biocide from leaking through opening  58 . Once nozzle  22  is withdrawn below the upper surface of wall  57 , and end  68  of flap  64  rests against the upper surface of wall  57 , opening  58  is then sealed by flap  64  to retain the biocide or other disinfectant within chamber  52 . 
         [0023]    A second embodiment of the invention which does not require flap  68  is illustrated in  FIG. 9-11 . The sterile liquid dispenser  110  is of the same type as disclosed in  FIG. 7  and comprises a hollow, rigid cylindrical container  120  which has hollow interior  111  containing sterile liquid and pressurized gas. Pressurized dispenser  110  has a cap  114 . The sterile liquid is injected into the interior  111  through bottom filling valve  115  which may be covered with a bottom cover secured at  116 . The retainer for the filling valve is shown at  117 . Typically the container  120  and cap  114  will be constructed of a rigid molded plastic such as a polypropylene or polycarbonate. Cap  114  may be screwed in place or may be sized and constructed to provide a friction or snap fit over neck  118  of container  120 . Dispenser  110  has a flexible nozzle  122  which is molded of rubber and is molded or welded integrally onto a rigid retainer ring  24  secured by glue or welding to neck  118  of container  120 . Elastomeric valve  130  functions as described above to dispense the sterile liquid after removing cap  114 . After dispensing the liquid, cap  114  is replaced on container  120  with nozzle  122  received in the hollow interior  134  of cap  114 . 
         [0024]    To preserve the sterility of the sterile liquid when the liquid is dispensed from nozzle  122 , cap  114  is provided with a quantity of biocide  150  or other disinfectant, such as a gel or liquid, stored in hollow cylindrical chamber  152 . Hollow cylindrical chamber  152  may be manufactured by ultrasonically welding or gluing a circular lid  156  to the inner surface of wall  155  of cap  114 . A stronger bond between cap  114  and lid  156  can be achieved by providing a downwardly extending curved element  159  which is secured by welding to the inner surface  153  of the upper wall of chamber  152 . Chamber  152  is separated from the hollow interior  134  of cap  114  by a rigid wall  157  having a central opening or aperture  158 . Annular ridge or shoulder  160 ,  161  extends downwardly from wall  157  around central opening  158 , and has a tapered inner surface  162  which receives the end of nozzle  122  and allows only the tip of nozzle  122  to extend into chamber  152 , as illustrated in  FIG. 11 . There may be breaks in the continuity of ridge  160  to release pressure when the tip of nozzle  122  is being guided into opening  158 . The size of central opening  158  and the relative configurations of the nozzle  122  and surface  162  of rib  160  are such that when the cap  114  is replaced on container  120 , the end of nozzle  122  can extend through opening  158  into chamber  152 , as shown in  FIG. 11 . Preferably the tip  170  of nozzle  122  tapers slightly inwardly as shown in  FIG. 11  where, for example diameter B is slightly less than diameter C. In this way the lower part of  170  contacts the inner edge of opening  158 . Also a narrow rubber collar (not shown) may be provided around the end of tip  170 , having width D, to compress the end of the tip and help keep liquid trapped within the end of tip  170 . 
         [0025]    Chamber  152  is wholly or partially filled with biocide  150  prior to use using a needle or other injector inserted through opening  158 . As will be apparent to those skilled in the art, various types of liquid, semi-liquid or gel biocides or disinfectants are suitable for this purpose. One class of suitable liquid disinfectants are non-toxic polymer disinfectants such as benzylkonium chloride in aqueous solution. A second class of suitable liquid disinfectants are salts of sorbate such as sorbic acid in aqueous solution. A third class are aromatic alcohols such as benzyl alcohol and a fourth is colloidal silver. Disinfectant gels such as peroxygel are also suitable. As described below, the nature of the biocide or disinfectant in terms of viscosity, density, surface tension and the like, as well as the diameter of the tip  170  of nozzle  122  will determine the possible ranges of diameters of the central opening  158 . 
         [0026]    When cap  114  is replaced over the dispensing nozzle  122 , as shown in  FIG. 9-11 , the end of nozzle  122  extends through central opening  158  and is immersed in the biocide  150 , thereby placing biocide in contact with the surface of the tip of nozzle  122 . The end of nozzle  122  is thus sterilized during storage and prior to each dispensing of liquid. When cap  114  is removed from container  120 , nozzle  122  is withdrawn from the central opening  158 . In this second embodiment the biocide or other disinfectant is retained within chamber  152  and prevented from leaking out opening  158  by surface tension. The surface tension created by the liquid is sufficient to prevent it from flowing out opening  158 . To achieve this function, the diameter of opening  158  must be within a suitable range, which will depend on the nature of the biocide or disinfectant. Whereas the preferred range for the diameter of opening  58  in the first embodiment is from 0.1 mm to 1 cm., the preferred range for the diameter of opening  158  in the second embodiment is from 0.2 mm to 5 mm depending on the type of biocide, with a preferred diameter of about 2.5 mm for liquid biocides. 
         [0027]    As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof.