Methods for intra-mold sterilization of a plastic-embedded metal component of a product, such as a medical lancet having a metal needle embedded within a plastic lancet body. For example, a lancet needle is retained within a mold, plastic is injected to encapsulate the needle, and a specified minimum temperature is maintained for a specified minimum cycle time. In example forms, the specified minimum mold temperature is at least about 370 degrees Fahrenheit and the specified minimum cycle time is at least about 10 seconds.

TECHNICAL FIELD

The present invention relates generally to the field of manufacturing medical devices and components, and more particularly to methods for sterilizing a plastic-embedded needle or other object during the manufacturing thereof.

BACKGROUND

Medical devices and components used for transcutaneous applications are typically sterilized prior to use. In most cases, the sterilization of medical devices and components occurs in a post-manufacturing process after the manufacturing and assembly thereof. For example, many medical devices are sterilized by autoclaving. Some items, however are not well suited to the heat required for autoclaving.

For example, medical lancets utilized for penetrating the skin of a human or animal subject to obtain a sample of blood typically include a metal needle embedded in a plastic lancet body. The sharp tip of the lancet is embedded in a protective plastic endcap that is molded together with the lancet body, typically as a unitary body having a thin frangible section to facilitate separation and removal of the endcap. The heat of autoclaving necessary to sterilize the metal needle would likely damage the plastic lancet body. As such, a standard practice in the industry is to sterilize lancets by delivery of gamma radiation through the lancets after manufacture. This method of sterilization typically requires considerable additional time and capital, leading to increased costs.

Many lancets are high-volume commodity products, where cost is a critical consideration. In order to minimize manufacturing costs, manufacturers traditionally have sought to shorten the in-mold cycle times of molding and de-molding lancets, since shorter cycle times typically allow higher production rates and thereby lower per-unit costs.

It is to the provision of improved manufacturing and sterilization methods that the present invention is primarily directed.

SUMMARY

In example embodiments, the present invention provides improved methods of manufacturing and sterilizing medical devices comprising plastic embedded metal components such as lancets. The method comprises an intra-mold sterilization process, wherein a metal component such as a lancet needle is disposed within a mold cavity, a plastic body is formed to encapsulate the metal component by injection molding, and maintaining the formed product in the mold at at least a specified mold temperature for at least a specified cycle time, effective to sterilize the metal component.

In another aspect, the invention relates to a method for simultaneously manufacturing and sterilizing a product. The method includes providing a tool; providing a portion of a medical device component within the tool; injecting a plastic within the tool to encapsulate the medical device component, the plastic being at a tool temperature; and maintaining the plastic at a specified minimum tool temperature for a specified minimum cycle time, effective to sterilize the metal component.

In still another aspect, the invention relates to a method for manufacturing a sterile lancet. The method includes providing a mold, the mold having a cavity; retaining a lancet needle within the cavity; injecting plastic within the cavity to encapsulate the needle therein, the plastic having a mold temperature; and maintaining the plastic at the mold temperature for a cycle time, effective to sterilize the metal component.

In another aspect, the invention relates to a sterile product manufactured according to any of the methods described herein, for example a sterile lancet so manufactured.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Generally described, the present invention relates to methods for sterilizing a plastic-embedded needle or other metal component of a plastic-embedded product. In example forms, the plastic-embedded needle is in the form of a lancet comprising a generally elongate needle entirely encapsulated within a plastic body wherein a sharp tip portion of the needle is embedded in a removable plastic cap. The lancet is preferably manufactured by utilizing a mold or tool wherein plastic can be injected within a cavity defined therein to form the lancet. The needle is placed within the cavity of the mold and the plastic injected therein entirely encapsulates the needle. The plastic being injected therein is preferably delivered at or heated to a specified temperature and maintains that specified temperature for a specified amount of time. Thus, by maintaining the plastic at a specified temperature for a specified amount of time within the cavity of the mold, the needle that is encapsulated within the plastic body is sterilized, which eliminates the need for post-manufacturing sterilization.

With reference now to the drawing figures, wherein like reference numbers represent corresponding parts throughout the several views,FIG. 1shows a plastic-embedded needle or lancet10comprising a sterile needle40, according to an example form of the present invention. The lancet10includes a generally elongate body comprising a body portion20, a removable cap30, and the needle40having a sharp tip portion44. The body portion20and the removable cap30entirely or substantially entirely encapsulate the needle or lancing needle40embedded therein (i.e., no portion of the needle that contacts the lancing site when the lancet is used is exposed externally of the plastic overmolding after manufacture, prior to removal of the endcap for use of the lancet). Preferably, the body portion20and the removable cap30are integrally formed as a single continuous molding, such that the needle40is entirely encapsulated therein. The needle can be a pointed tip type or a blade tip type needle.

FIG. 2shows a mold or tool50in an open position according to an example embodiment of the present invention. Preferably, the mold50is utilized to manufacture the lancet10. In example forms, the mold10comprises a first mold part60and a second mold part70. The first mold part60comprises a first cavity64and the second mold part70comprises a second cavity74. Generally, the first and second cavities64,74are sized, shaped and formed accordingly to form the body portion20and removable cap30, respectively to be produced. Preferably, the needle40is placed substantially within the first cavity64of the first mold part60to be encapsulated by the body portion20and the removable cap30when the mold is closed and plastic is injected therein, as is commonly referred to as plastic over-molding.

FIG. 3shows the mold50in a closed position wherein the lancet10is formed in the cavities64,74. Generally, the first and second mold parts60,70abut each other such that the cavities64,74communicate with each other to define a single mold cavity in which the product is to be formed. With the cavities communicating therewith, plastic is injected therein to fill the joined cavities64,74and to entirely encapsulate the needle40, which in turn forms the lancet10.

In preferred example embodiments, the needle40that is encapsulated in the integrally formed body portion20and removable cap30is sterilized during the manufacture of the lancet10, such that a separate post-production sterilization step is not required. In one form, sterilizing the needle40during the manufacture of the lancet10is accomplished by maintaining at least a specified minimum temperature (e.g., mold temperature) of the mold and/or plastic being injected therein for at least a specified minimum amount of time (e.g., cycle time), effective to sterilize the needle or other embedded object. In example embodiments, the specified minimum temperature of the mold and/or plastic is at least about 370 degrees Fahrenheit (° F.), more preferably at least about 375° F., and more preferably at least about 400° F. The specified amount of time to maintain the specified minimum temperature (“cycle time”) is at least about 10 seconds, or alternatively at least about 14 seconds, or alternatively at least about 15 seconds, or alternatively at least about 20 seconds. To maintain the specified minimum temperature, one or more heating elements80, hot runners, and/or other means of heating the mold may be provided. After maintaining the specified minimum temperature for a specified amount of time, the mold and/or plastic is cooled (allowing the body portion20and removable cap30to solidify), and the mold50is then moved to an open position wherein the lancet10is ejected therefrom. Thus, the needle40is sterilized during the manufacture of the lancet10, which eliminates the need for post-manufacturing sterilization.

In an additional example embodiment, the present invention relates to a method for sterilizing a medical device component. The method includes providing a mold; providing a needle within the mold; injecting plastic within the mold to encapsulate the needle, the plastic having a mold temperature; and maintaining the temperature of the plastic at the mold temperature for a cycle time, effective to sterilize the needle or other embedded object. Similarly, according to another example embodiment, the present invention relates to a method for simultaneously manufacturing and sterilizing. The method includes providing a tool; providing a portion of a medical device component within the tool; injecting a plastic within the tool to encapsulate the medical device component, the plastic being at a tool temperature; and maintaining the plastic at the tool temperature for a cycle time effective to sterilize the needle or other embedded object. Additionally, in yet another example embodiment, the present invention relates to a method for manufacturing a sterile lancet. The method includes providing a mold, the mold having a cavity; placing a lancet needle within the cavity; injecting plastic within the cavity to encapsulate the needle therein, the plastic having a mold temperature; and maintaining the plastic at the mold temperature for a cycle time effective to sterilize the needle or other embedded object. The invention also includes a product having a metal component encapsulated with plastic, for example a lancet having a metal needle encapsulated in a plastic lancet body, produced according to any of the methods described herein.