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Method of purification of polymeric medical device materials using continuous soxhlet extraction

Inactive Publication Date: 2005-05-19
LAI YU CHIN +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0008] Polymeric medical device materials such as those useful in the manufacture of contact lenses, corneal inlays and intraocular lenses are produced with sufficiently low levels of contaminants and / or leachables in accordance with the present invention through a novel continuous soxhlet extraction process. The continuous soxhlet extraction process of the present invention eliminates difficulties formerly encountered in the purification of polymeric medical device materials using batch extraction. The subject continuous soxhlet extraction process is effective in achieving sufficiently low levels of contaminants and / or leachables in cases where the target application of the medical device has very stringent requirements in terms of low levels of impurities and / or leachables. Additionally, the continuous soxhlet extraction process of the present invention is relatively simplistic in that it does not require the use of large quantities of solvent and does not require frequent solvent replacement. Because there is no need for frequent solvent replacement, extraction disruptions and solvent costs are reduced. Additionally, continuous soxhlet extraction in accordance with the present invention is an environmentally friendly purification process since large quantities of dirty waste solvent are not produced.
[0010] Another object of the present invention is to provide an effective purification process for polymeric medical device materials with target applications having very stringent requirements in terms of low levels of impurities and / or leachables.
[0011] Another object of the present invention is to provide an effective purification process for polymeric medical device materials that reduces clean solvent requirements.
[0012] Another object of the present invention is to provide an effective purification process for polymeric medical device materials that reduces solvent waste production.
[0013] Still another object of the present invention is to provide an effective purification process for polymeric medical device materials that is economical and environmentally friendly.

Problems solved by technology

If not removed, contaminants and / or leachables in the material of medical devices may cause adverse effects on patient health or the ultimate outcome of the medical procedure.
Such adverse effects can be so severe as to defeat the original purpose of conducting the medical procedure.
However, batch extraction may not be sufficiently effective in cases where the target application of the medical device has very stringent requirements in terms of low levels of impurities and / or leachables.
Additionally, batch extraction is cumbersome in that it requires the use of large quantities of clean solvent and requires frequent solvent replacement.
Frequent solvent replacement causes extraction disruption and increased costs.
Batch extraction is likewise not evironmentally friendly in that the process creates large quantities of dirty waste solvent.

Method used

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  • Method of purification of polymeric medical device materials using continuous soxhlet extraction

Examples

Experimental program
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Effect test

example 1

Static Solvent Extraction at Ambient Temperature

[0024] Ten (10) intraocular lenses with a dry weight of 0.3231 g, were submerged and settled on the bottom of a flask filled with 180 cc of isopropanol (IPA). After 3 hours, all lenses were recovered and dried in vacuum oven at 70° C. overnight. The weight of the dried lenses was 0.3144 g, for a loss of 2.69 percent.

example 2

Batch Soxhlet Extraction with Lens Samples in Teflon™ Holder

[0025] A soxhlet extractor capable of holding 180 cc of solvent without overflow was attached to a 500 mL round bottom flask filled with IPA and a refluxed condenser. The variance was adjusted and the IPA was heated to reflux. The temperature of the main body of the soxhlet extractor was found to be 75° C.

[0026] Ten (10) intraocular lenses with a dry weight of 0.3223 g were placed in open cages cut out from circular Teflon™ (E.I. Dupont de Nemours, Wilmington, Del.) plates (5 cages on each plate). The Teflon™ plates were then stacked vertically and held together using a central holder. The holder with the plates and lenses was then placed in the soxhlet extractor and underwent extraction for three hours. During the extraction, all solvent siphoned back into the flask once the level of the solvent within the extractor reached a level above that of the peak of the liquid arm. After three hours of extraction, the lenses were...

example 3

Batch Soxhlet Extraction with Lens Samples in Glass Thimble with Coarse Sintered Glass Filter

[0027] Ten (10) intraocular lenses having a dry weight of 0.3216 g were placed in a glass thimble on top of a coarse sintered glass filter placed in the bottom thereof. The glass thimble was then placed in a soxhlet extractor attached to a flask and a condenser. The lenses then underwent extraction for three hours. During the extraction, all solvent except for the solvent within the glass thimble was recycled once the level of the solvent within the extractor reached a level above that of the peak of the liquid arm. Accordingly, the lenses were continuously submerged in solvent throughout the extraction process although solvent flow was not continuous due to recycling. After extraction, the lenses were removed from the glass thimble and air dried for three hours. The lenses were then dried under vacuum at 70° C. overnight. The weight of the dried lenses was 0.3105 g, for a loss of 3.45 perc...

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Abstract

A process for removing contaminants and / or leachables from polymeric materials useful in the manufacture of biocompatible medical devices such as intraocular lenses, corneal inlays and contact lenses using continuous soxhlet extraction.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method of polymer purification through continuous soxhlet extraction useful in the manufacture of biocompatible polymeric medical devices. More particularly, the present invention relates to a method of removing contaminants and / or leachables from polymeric materials useful in the manufacture of biocompatible medical devices such as intraocular lenses, corneal inlays and contact lenses using continuous soxhlet extraction. BACKGROUND OF THE INVENTION [0002] Medical devices are designed for particular medical applications. Many medical devices are manufactured from polymeric materials, which must be free from contaminants and / or leachables to be useful for the particular medical application for which it is designed. If not removed, contaminants and / or leachables in the material of medical devices may cause adverse effects on patient health or the ultimate outcome of the medical procedure. Such adverse effects can be so s...

Claims

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Application Information

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IPC IPC(8): A61F2/16C08J7/00
CPCA61F2/16C08J2401/02C08J2383/04C08J7/047C08F6/28C08G77/34C08L33/00B01D11/00C08J7/0427
Inventor LAI, YU-CHINRUSCIO, DOMINIC V.VANDERBILT, DAVID P.
Owner LAI YU CHIN
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