Granted Patent B2

US 12,298,213 · App. 17/625,032 · Granted May 13, 2025

Inventors: Amer Ebied (London, CA); Eric D. Landry (London, CA); Peng Xiang (London, CA); Solmaz Karamdoust (London, CA)

G01N1/4055B01D11/0288G01N33/4833B01D2221/10G01N2001/4061

Abstract

Claims (18)

1. A method for the extraction of one or more polymeric biomaterials and/or pharmaceutical agents from an implantable medical device, said method comprising the steps:

i) excised polymers containing tissue and implantable device are dissolved in one or more solvents selected from the group comprising of oxygenated solvents, hydrocarbon solvents, halogenated solvents, organic solvents, aqueous buffers, alkaline solutions, and caustic solutions, thereby producing an extraction solution which is collected;

ii) the excised polymers are re-washed with solvents thereby producing one or more extraction solutions of polymer degradants;

iii) the solvent is removed from the different extracts under a stream of nitrogen gas and/or freeze-dried until dryness and then further dried under vacuum to produce a dried extract;

iv) the dried extract is fully dissolved in a mobile phase under gentle stirring for 2 to 24 hours between 25-70° C.; and

v) the dissolved extract is filtered and introduced into autosampler vials for analysis.

2. The method of claim 1 , wherein the medical device is a stent, pharmaceutical agent delivery vehicle, scaffold, or sutures.

3. The method of claim 2 , wherein the implanted medical device has been excised from animal organ tissue.

4. The method of claim 1 , wherein the mobile phase is selected from the group comprising of oxygenated solvents, hydrocarbon solvents, halogenated solvents, organic solvents, aqueous buffers, alkaline solutions, and caustic solutions.

5. A method for determining a degradation profile and concentration of one or more polymers or pharmaceutical agents from an excised previously implanted medical device comprising the following steps:

i) extracting one or more biodegradable polymers (or pharmaceutical agents) from a medical device, wherein excised polymer containing tissue and medical device are dissolved in a solvent selected from the group comprising chloroform (CHCl 3 ) or HFIP (1,1,1,3,3,3-hexafluoro-2-propanol), thereby producing an extraction solution which is collected, filtered;

ii) the excised polymers are re-washed with the solvent thereby producing one or more washed extraction solutions, each of which are filtered;

iii) the washed filtered extraction solutions are combined with the filtered extraction solution, producing a combined extract;

iv) the solvent is removed from the combined extract under a stream of nitrogen gas until dryness and then further dried under vacuum to produce a dried extract;

v) the dried extract is fully dissolved in the solvent for further analysis;

vi) determining baseline data including number-average molecular weight (Mn), and weight-average molecular weight (Mw), and calculating polydispersity index (PDI-Mw/Mn) as a measure of molecular weight distribution of a corresponding naïve non-implanted polymer;

vii) determining degradation data including number-average molecular weight (Mn), and weight-average molecular weight (Mw), and calculating polydispersity index (PDI=Mw/Mn) as a measure of molecular weight distribution of the polymer at various time points after implantation; and

viii) correcting the degradation data using the baseline date to provide an accurate degradation profile of the polymer from the excised previously implanted medical device at various time points.

Assignments (1)

Continuity (2)

References Cited (18)