Medical containers

Details Medical containers Medical containers

1999-11-23

2004-03-30

Nolan, Sandra M. (Department: 1772)

Stock material or miscellaneous articles

Hollow or container type article

Polymer or resin containing

C428S035200, C428S213000, C428S349000, C428S516000

Reexamination Certificate

active

06713137

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a multilayered film suitable for the manufacturing of flexible containers for medical fluids. The film comprises polyolefins only and is assembled with coextrusion into several polyolefinic layers with complementary characteristics to build up a flexible film with high clarity. Further, the film is autoclavable and capable of forming weldings of controlled strength with conventional welding equipment.
BACKGROUND OF THE INVENTION
The efforts of developing containers of polymeric materials for parenterally administerable medical products to replace glass bottles are described in the International Patent Application PCT/SE97/00590. To find acceptance with authorities giving approvals to medical systems, such polymeric containers after being filled and finally sealed must be capable of being sterlized by high pressure steam (i.e. autoclavation at 121° C. for at least 15 minutes) with a maintained barrier capacity against the environment and safety from migration of potentially hazardous agents. Moreover, the container must maintain its shape, have a suitable aesthetic value and be easy to recycle after use. It is also of considerable importance that the material must have low production costs, since it is intended to be used for packaging medical fluids produced in large scale, including parenteral nutrient solutions.
As disclosed in the aforementioned International Patent Application, a polymer material suitable for a container for medical fluids for parenteral use must comply with several important requirements. The material must be possible to be permanently welded to a bag including other details of polymeric material, for example conventional saddle-formed port system and filling ports. It must also admit the formation of welded seams of different strength, in particular (weak) peclable seal seams possible to rupture manually, as well as permanently sealing welded seams, preferably by simple modifications of the welding conditions.
The material should be substantially impermeable for water vapor even during steam sterilization, but need not be completely airtight, since in many applications where an effective barrier against environmental oxygen is required to protect an oxygen-degradable product, it is advantageous to use a secondary outer airtight envelope enclosing the inner container filled with the product together with a sachet comprising an oxygen scavenger composition. In such a case, it is of advantage if the material of the container could permit an oxygen transfer from the degradable fluid to the oxygen scavenger for consumption of substantially all the dissolved residual oxygen in the product.
A polymeric material suitable for a medical container with many of mentioned characteristics would preferably comprise polyolefins, since they are cheap and chemically inert and free from potentially hazardous migrating agents compared to for examples halogenated polymers. With respect to this, various qualities of polyethylene and polypropylene are regarded as suitable materials. However, many polyethylenes are too soft and lack in heat resistance when heat sterilizing temperatures are reached which often is required in the pharmaceutical industry.
For many reasons, it would be desirable to use pure polypropylenes for the films when considering their capacity of withstanding autoclavation and maintain a barrier against water vapor and its favorable optical properties. However, pure polypropylenes are brittle and rigid, so in practice they often need to be blended with polymers which impart a softness and flexibility to provide a material with higher mechanical processability, such as polyethylene and certain thermoplastic elastomers.
In order to overcome the mentioned drawbacks of pure polyolefins, such as the insufficient flexibility and brittleness of polypropylenes and the softness and low melting point of polyethylenes, multilayered film materials consisting of several layers with complementary properties frequently have been developed for use in the packaging of medical fluids. For example, polypropylenes often have been combined with a supplementary elastomer to improve its flexibility and resilience. For multilayered materials, it has been preferred to have an inner, sealant layer comprising polypropylene to benefit from its compatibility to stored fluids and for facilitating the manufacturing of a container by means of different welding techniques. It has also been a desire to introduce a flexible layer with a high melting point which provides the material with an improved stability at the high temperatures locally reached during the welding. If such a material is comprised in a multilayered film, it is placed as an outer, release layer. In addition it is often requested that such a layer shall be printable in order to carry important information to the user and for this reason, it must not allow migration from the printing ink. Suitable materials for such an outer layer can be found among certain polyesters and copolymers thereof and in particular cycloaliphatic polyesters. To obtain a suitable flexibility to a multilayered film an elastomer may be introduced in the inner layers. Examples of this type of multilayered films are found in EP 0 228 819 and in EP 0 199 871. Such a material suitable for medical containers is Excel® from McGaw Inc. and as disclosed in the aforementioned PCT/SE97/00590, it has an acceptable compatibility with lipophilic fluids, such as the parenteral nutrient Intalipid® fat emulsion, although a certain amount of the elastomer SEBS (styrene-ethylene-butadiene-styrene) is compounded with the polypropylene in the inner, sealant layer facing the lipids during storage. Also in WO 95/26177, it is disclosed a similar material having a sealant layer comprising a polypropylene copolymer and an elastomer in a mixture. Furthermore, EP 0 229 475, EP 0 230 114 and EP 0 301 773 disclose multiple layer films comprising blends of polyolefinic polymers and elastomer modifiers.
Even if the mentioned multilayered films having elastomers and other polymers, besides polyolefins are suitable in many applications of medical containers, it is desirable to use only polyolefin materials in the packaging of medical fluids, especially in large scale packaging of parenteral nutrients including lipid emulsions. The most important reasons are the comparatively higher costs of many elastomers, the complicated production of multilayered materials including elastomers and that the remaining uncertainty of how such compounds may be affected during extended storage of particularly lipophilic medical fluids. Certain elastomer containing films have also demonstrated a tendency to delaminate, especially after autoclavation, due to low compatibility between the layers.
It would therefore be of great advantage to provide multilayered films only made from polyolefins of medical grade derived from a cheap source and yet retain the mentioned advantageous characteristics of the blended multilayered films discussed above.
EP 0 197 054 discloses a film having an outer high density polyethylene layer and an inner middle density polyethylene layer, suitable for autoclavable flexible containers. This film is reported to overcome difficulties in maintaining the shape of the container after autoclavation without compromising in other characteristics like impact strength and optical clarity. However, this type of film will not be suitable for welding seals of different strength as required for multi-chamber containers having easy rupturable seals as partitions between the chambers for readily mixing their contents before administration. Generally, layers made from polyethylene, due to their low softening temperature, hardly will be able withstand high pressure steam sterilization at 121° C. for required autoclavation periods over 15 minutes without being deformed. Moreover, polyethylene layers will reduce the impact strength of the material.
EP 0 216 639 describes a multi-layer film for packaging of physiologic solutions comprising at

Affiliated with

Also associated with

Rating

Medical containers does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Medical containers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Medical containers will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3276732