Effect of radio-opaque filler on biodegradable stent properties.
The effect of the addition of a radio-opaque filler, barium sulfate (BaSO(4)), on the mechanical properties of a biodegradable amorphous polymer film (poly-lactic-co-glycolic acid, PLGA) was studied, as a function of degradation. With up to about 18% loading (v/v), the modulus of the filled polymer increases; beyond this concentration, agglomerates are formed. The filled systems are also radio-opaque, over a thickness range of 0.07-0.19 mm in stent form (helicoidal). These stents were then immersed in phosphate buffer pH 7.4 at 37(o)C for 2 weeks. The radial strength of stent was measured by using a compression test. It was found that filler-loaded stent (FS) increased in radial strength by about 4 times (14.95 +/- 1.20 N/mm) compared to the unfilled stent (UFS). However, both samples lost radial strength as the polymer degraded in buffer, but FS retained 60% (9.05 +/- 0.07 N/mm) of its strength after 2 weeks whereas only 36% (1.39 +/- 1.04 N/mm) was retained for UFS. Moreover, UFS lost its helical shape after 3 weeks. The findings have implications for optimization of degradable stent formulations.
Chan
W A
WA
School of Materials Science & Engineering, Nanyang Technological University, N4.1, B1-04 Nanyang Avenue, Singapore 637819.
Bini
T B
TB
Venkatraman
Subbu S
SS
Boey
F Y C
FY
D020341:Absorbable Implants; D001466:Barium Sulfate; D001672:Biocompatible Materials; D019344:Lactic Acid; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers; D015607:Stents
D001672:Biocompatible Materials; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D001466:Barium Sulfate; D011100:Polyglycolic Acid; D019344:Lactic Acid