The present invention relates generally to the field of medical devices used for delivering parenteral drugs and more particularly to dual-chamber prefilled syringe where two or more components, for example, a solid powder and a liquid solvent are previously filled respectively into separate dual chambers. The present invention is designed for proper and accurate dosing of parenteral drugs.

Background of the Invention

Dual-chamber prefilled syringes are widely known in the art for their convenient use and to avoid any bacterial contamination. Generally, a dual-chamber prefilled syringe contains a solid powdered medicine of a predetermined quantity sealed in an inner chamber and a liquid solvent of a predetermined quantity sealed in an outer chamber. When used, the plunger is pushed forward to create a hydraulic pressure, which allows the liquid solvent to mix with the powdered medicine to produce a parenteral solution.

Despite there have been numerous advancements and improvement made in dual- chamber syringe designs but there remains a continuous concern for proper and accurate dosing parenteral drugs.

Summary of the Invention

In order to overcome the concern of proper and accurate dosing of parenteral drugs, the inventors designed an improved dual-chamber prefilled syringe assembly comprising a flow control gasket, which is positioned to control the flow of a fluid from one chamber to another chamber.

The present invention provides a dual-chamber syringe assembly comprising an outer barrel and an inner barrel, which is coaxially moveable inside the outer barrel. The inner barrel comprises a plunger and a flow control gasket positioned at a proximal end of the plunger.

The present invention further provides a method of using dual-chamber syringe assembly comprising a flow control gasket designed for proper and accurate dosing of parenteral drugs. This invention, including its embodiment and other features, will become more apparent from the following detailed description with reference to the accompanying drawings.

Brief description of drawings

The present invention may best be understood by reference to the following description, taken in connection with the accompanying drawings in which the reference numerals designate like parts throughout the figures thereof and wherein:

FIG 1 illustrates various components of a dual-chamber delivery device, in accordance with an embodiment of the present invention.

FIG 2 illustrates a flow control gasket of the dual chamber delivery device, in accordance with an embodiment of the present invention.

Detailed description of various embodiments

The present invention describes a dual-chamber delivery device for a homogenous mixture of two components, for example, a powdered medicine and a liquid solvent previously filed respectively in separate chambers of the device.

The device may be used for a variety of applications, such as for dosage of parenteral drugs and for providing a solution to another object or device, for example for lubricating a mechanical device.

In accordance with an embodiment of the invention, the device comprises an assembly of an outer barrel to store a powdered substance in a predetermined quantity, an inner barrel to store a liquid substance, which is coaxially moveable within the outer barrel, and a plunger for creating hydraulic pressure and comprises a flow control gasket having an aperture for transversing liquid substance to the outer barrel. The inner barrel has flow control gasket at one end and another end is designed to accommodate the plunger. The outer barrel includes a needle hub at one end designed to seat a needle unit, while the other end is designed to accommodate the inner barrel.

The thickness of the flow control gasket can be modified to adjust lower to a higher range of viscosity. In other words, the elasticity of the flow control gasket can be modified to control the flow of the liquid substance inside the inner barrel.

It is an important aspect of the present invention that the viscosity of the liquid substance is irreversibly proportional to the thickness/elasticity of the flow control gasket, which helps in maneuvering flowability of the liquid substance.

The moisture transmission rate may be controlled by selecting Cyclic Olefin Copolymer (COC) for constructing both inner and outer barrels having water uptake less than 0.001 % and water permeability (g x mm/m ² x day) of 0.02-0.04. In another variation of the embodiment, both inner and outer barrels being made of polypropylene or the other polymer materials.

According to one aspect of the present invention, the inner and outer barrels may have gasket made from bromo butyl to act as sealing and the gasket is so designed to have three O-rings to avoid moisture transmission rate. In another variation of the embodiment, the gasket is made of silicon rubber or the other elastomer material.

The needle unit may be fitted at the needle hub for the purpose of administering a mixture of the product and the solvent. Further, a cylindrically shaped flow control gasket is provided in the head member of the inner barrel. The aperture at the end may be facing towards the product available in the outer barrel. The aperture opens only due to the pressure created with the help of plunger.

An embodiment of the present invention is disclosed in FIG 1 . The delivery device 100 comprises an assembly of an outer barrel 102 and an inner barrel 103, which is designed to be slidable within the outer barrel 102. The front end of the outer barrel 102 includes a needle hub 101 so designed to receive a needle unit. The needle hub 101 may be sealed or covered by a protecting cap or may have a threading to accommodate the needle unit. The outer diameter of the inner barrel 103 is less than the inner diameter of the outer barrel 102, designed to receive the inner barrel 103 inside the outer barrel 102.

In one aspect of the embodiment of the invention, the outer barrel 102 may be prefilled with a product either in powder or liquid form. The product may be lyophilized drug or a component of a combination drug. The inner barrel 103 may include a solvent to be mixed with the product. According to one of the embodiment, the inner barrel 102 and the outer barrel 103 are made of a material which is compatible with the substance stored

respectively in them.

A distal end of the outer barrel 102 may be provided with an outer barrel finger rest 105 and may also include an opening to receive the inner barrel 103. The inner barrel 103 comprises a flow control gasket 104 positioned at its proximal end to transverse the solvent from the inner barrel 103 to the outer barrel 102. The broad end of the flow control gasket 104 may be towards solvent receiving end and the narrow end may be towards solvent delivering end.

In another aspect of the embodiment, the inner barrel 103 is placed with the bottom surface 109 close to the product. To prepare the solution, the plunger 107 is moved inside the inner barrel 103 and to aid the plunger movement, a user may rest fingers on the outer barrel finger rest 106 and the thumb may be rested on the thumb rest 108. The forward motion of the plunger 107 may help to open the aperture in the flow control gasket 104 provided on the bottom surface109 to allow the solvent from the inner barrel 103 to the outer barrel 102. Further, the varying amount of pressure on the plunger 107 creates pressure on the flow control gasket 104, which results in nozzle effect.

In yet another aspect of the embodiment, the flow control gasket 104 extends radially outwards from the first surface of the inner barrel 103 to the inner surface of the outer barrel 102, such that it seals the inner barrel 103 from the outer barrel 102 in a liquid-tight manner. Further, the inner barrel 103 along with the gasket 104 is provided inside the outer barrel 102 such that the outer barrel 102 provides a first compartment to store the medical component. The flow control gasket 104 is provided near the bottom surface 109 of the inner barrel 103, such that the flow control gasket 104 allows the flow of substances from inner barrel 103 to the outer barrel 102 and blocks the reverse flow of substance from the outer barrel 102 to the inner barrel 103. Further, the gasket 104 is designed such that it slides axially inside the outer barrel 102 under pressure. The bottom surface of the inner barrel 103 is configured to receive a plunger head with gasket 1 10.

The medical component may be in the form of at least one of powder, granules, tablets, liquids and so on. The inner barrel 103 is configured to store a dissolving/ dispersing agent such as a liquid that is configured to dissolve the medical component stored in the outer barrel 102. It should be noted that the substance provided in the outer barrel 102 and the inner barrel 103 such as medical component and the dissolving / dispersing agent respectively are provided for the ease of understanding. However, certain embodiments may have different substance or combination of a different substance in outer barrel 102 and inner barrel 103 without other deterring the intended function of the delivery device 100 as can be deduced from this description.

In yet another aspect of the embodiment, the flow control gasket 104 prevents the passage of dissolving/dispersing agent from the inner barrel 103 to the outer barrel 102, there by stores the medical component and dissolving / dispersing agent independently from each other. Flow control gasket 104 with an aperture opens only when the pressure created by the plunger 107. In one embodiment, the flow control gasket 104 prevents the passage of dissolving / dispersing agent from the inner barrel 103 to the outer barrel 102, thereby stores the medical component and dissolving / dispersing agent independently from each other. Further, upon actuating the plunger 107 by applying a first pressure, the plunger 107 pressurize the dissolving / dispersing agent stored inside the inner barrel 103 to move out of the inner barrel 103 and flow into the outer barrel 102 through the flow control gasket 104 with an aperture, thereby effecting a desired action such as dispersing, dissolving or mixing between the medical component and the dissolving / dispersing agent. In this way, an injecting medicine is obtained in the outer barrel 102. By further pushing the plunger 107 by applying a second pressure which is higher than that of first pressure, the inner barrel 103 along with the flow control gasket 104 slides inside the outer barrel 102 and pressurize the injecting medicine obtained inside the outer barrel 102 to move out of the outer barrel 102 through the needle hub 101 .

According to one aspect of the embodiment, a non-returnable valve is mounted between the flow control gasket 104 and the plunger 107.

Another embodiment of the present invention is disclosed in Fig. 2. A distal end, with respect to the needle hub 101 , of the outer barrel 102 may be provided with the outer barrel finger rest 105 and a proximal end may be provided with the needle hub 101 .

Further, the distal end may also include an opening to receive the inner barrel 103. The needle hub 101 may be coaxial to the outer barrel 102. In an implementation, the needle hub 101 may be a cylindrically shaped projection having apertures of equal diameter at both ends of the cylinder.

According to one aspect of the embodiment, the aperture at the tip of the needle hub 101 , may be sealed with a rubber seal or an air-tight seal or nozzle cap to prevent exposure of the product to moisture. The seal may be easily punctured with the help of a needle.

Alternately, the rubber seal may be a thin seal, which maybe punctured on the application of pressure through the product-solvent solution.

According to another aspect of the embodiment, the needle hub 101 may be fitted with a protecting cap. The cap may be fitted to provide a seal at the opening end of the needle hub 101 . Further, the cap may prevent the product in the outer barrel 102 from being exposed to moisture and microbial contaminants. While administering the solution, the cap provided on the needle hub 101 may be removed and the needle unit may be seated on the needle hub 101 .

In the foregoing description, the method and device of the present invention have been described with reference to preferred embodiments. It is to be understood and expected that variations in the principles of the method and device herein disclosed may be made by one skilled in the art and it is intended that such modifications, changes, and substitutions are to be included within the scope of the present invention as set forth in the appended claims (if any are included). The specification and the drawings are accordingly to be regarded in an illustrative rather than in a restrictive sense.