Vials oversealing

A packaging component means any single part of a container closure system. Typical components are containers (e.g., ampules, vials, bottles), container liners (e.g., tube liners), closures (e.g., screw caps, stoppers), closure liners, stopper overseals, container inner seals, administration ports [e.g., on large-volume parenterals (LVPs)], overwraps, administration accessories, and container labels [4],... 

Primary pack Type 1 clear glass vial (10 m L) Rubber stopper Aluminium overseal... 

Special mention should be made of closures for IV solutions. The use of any screw closure with an inner rubber wad or plug always presents an unscrewing risk due to a watch spring effect. In addition, threading may hide a contamination due to residual cooling water. An overseal-type closure, similar to that employed for vials, appears to offer advantages (DIN Standard). 

Metal closures are still in wide use, being manufactured from tinplate, aluminium and alloys of aluminium, and these cover screw closures, various forms of lidding, aerosol valves, overseals (e.g. for vials), etc. 

Crimping—shaping, folding and crimping, e.g. collapsible tubes (metal). Aerosol valves for glass bottles. Overseals for injection vials. 

The primary seal is formed between the underside of the closure flange and top of the vial the secondary seals are formed between the vial side wall and the plug portion of the closure (termed flange seal and bore seal). It has been postulated that correct selection and specification of the aluminium overseal is as important as the primary packaging materials, since it forms an integral part of the sealing mechanism. 

Closures may be fiat discs or wads that rest on the vial, making contact with the flange, and being held in place by an overseal. This type of presentation is not used commonly nowadays, having been replaced in the main by plugs that fit into the neck of the vial (Fig. 2). These plugs also make contact with the flange of the vial and are held in place by an oversea . 

After the product has been dried to a desired moisture content, the vials are stoppered and removed from the freeze-drier before oversealing. Vials may be back-filled with an inert gas such as nitrogen or helium just prior to stoppering. When open ampoules or trays (which cannot be stoppered within the freeze-drier) are used instead of vials, it is necessary to use alternative sealing techniques in order to prevent the ingress of moist air into the dried product. 

The risk of vial breakage may be significant during oversealing particularly when automatic equipment is used for this operation. Two types of mechanical oversealers are commonly used ... 

Both types of oversealer require careful adjustment to ensure an acceptable seal with minimum vial breakage. Alternatively, vials may be sealed with a screw cap rather than an aluminium overseal and these alternatives may be safer to use when hazardous products are processed. 

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