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Biocompatibility and biodegradation studies of subconjunctival implants in rabbit eyes.

Peng Y, Ang M, Foo S, Lee WS, Ma Z, Venkatraman SS, Wong TT - PLoS ONE (2011)

Bottom Line: PLC70/30 15±0.6%; P = 0.91) over a period of 6 months.Histology, immunohistochemistry and immuno-fluorescence also revealed no significant inflammatory reaction from either of the microfilms, which confirmed that both microfilms are biocompatible.The duration of the drug delivery can be tailored by selecting the materials, which have different degradation kinetics, to suit the desired clinical therapeutic application.

View Article: PubMed Central - PubMed

Affiliation: School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore.

ABSTRACT
Sustained ocular drug delivery is difficult to achieve. Most drugs have poor penetration due to the multiple physiological barriers of the eye and are rapidly cleared if applied topically. Biodegradable subconjunctival implants with controlled drug release may circumvent these two problems. In our study, two microfilms (poly [d,l-lactide-co-glycolide] PLGA and poly[d,l-lactide-co-caprolactone] PLC were developed and evaluated for their degradation behavior in vitro and in vivo. We also evaluated the biocompatibility of both microfilms. Eighteen eyes (9 rabbits) were surgically implanted with one type of microfilm in each eye. Serial anterior-segment optical coherence tomography (AS-OCT) scans together with serial slit-lamp microscopy allowed us to measure thickness and cross-sectional area of the microfilms. In vitro studies revealed bulk degradation kinetics for both microfilms, while in vivo studies demonstrated surface erosion kinetics. Serial slit-lamp microscopy revealed no significant inflammation or vascularization in both types of implants (mean increase in vascularity grade PLGA50/50 12±0.5% vs. PLC70/30 15±0.6%; P = 0.91) over a period of 6 months. Histology, immunohistochemistry and immuno-fluorescence also revealed no significant inflammatory reaction from either of the microfilms, which confirmed that both microfilms are biocompatible. The duration of the drug delivery can be tailored by selecting the materials, which have different degradation kinetics, to suit the desired clinical therapeutic application.

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Change of film thickness of PLGA50/50 and PLC70/30 in vitro (PBS, pH 7.4).
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pone-0022507-g005: Change of film thickness of PLGA50/50 and PLC70/30 in vitro (PBS, pH 7.4).

Mentions: The thickness of PLGA50/50 was unchanged (within 10%) in the first 21 days, but a sudden drop of 60% occurred on the day 28, and immeasurable on day 42,. From the observed changes on mass loss, PLGA50/50 lost 90% of its initial weight on day 42, and corresponded to the change in film thickness. In contrast, PLC70/30 maintained its shape throughout the entire duration of the study period, with minimal change in film thickness (Figure 5).


Biocompatibility and biodegradation studies of subconjunctival implants in rabbit eyes.

Peng Y, Ang M, Foo S, Lee WS, Ma Z, Venkatraman SS, Wong TT - PLoS ONE (2011)

Change of film thickness of PLGA50/50 and PLC70/30 in vitro (PBS, pH 7.4).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3142149&req=5

pone-0022507-g005: Change of film thickness of PLGA50/50 and PLC70/30 in vitro (PBS, pH 7.4).
Mentions: The thickness of PLGA50/50 was unchanged (within 10%) in the first 21 days, but a sudden drop of 60% occurred on the day 28, and immeasurable on day 42,. From the observed changes on mass loss, PLGA50/50 lost 90% of its initial weight on day 42, and corresponded to the change in film thickness. In contrast, PLC70/30 maintained its shape throughout the entire duration of the study period, with minimal change in film thickness (Figure 5).

Bottom Line: PLC70/30 15±0.6%; P = 0.91) over a period of 6 months.Histology, immunohistochemistry and immuno-fluorescence also revealed no significant inflammatory reaction from either of the microfilms, which confirmed that both microfilms are biocompatible.The duration of the drug delivery can be tailored by selecting the materials, which have different degradation kinetics, to suit the desired clinical therapeutic application.

View Article: PubMed Central - PubMed

Affiliation: School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore.

ABSTRACT
Sustained ocular drug delivery is difficult to achieve. Most drugs have poor penetration due to the multiple physiological barriers of the eye and are rapidly cleared if applied topically. Biodegradable subconjunctival implants with controlled drug release may circumvent these two problems. In our study, two microfilms (poly [d,l-lactide-co-glycolide] PLGA and poly[d,l-lactide-co-caprolactone] PLC were developed and evaluated for their degradation behavior in vitro and in vivo. We also evaluated the biocompatibility of both microfilms. Eighteen eyes (9 rabbits) were surgically implanted with one type of microfilm in each eye. Serial anterior-segment optical coherence tomography (AS-OCT) scans together with serial slit-lamp microscopy allowed us to measure thickness and cross-sectional area of the microfilms. In vitro studies revealed bulk degradation kinetics for both microfilms, while in vivo studies demonstrated surface erosion kinetics. Serial slit-lamp microscopy revealed no significant inflammation or vascularization in both types of implants (mean increase in vascularity grade PLGA50/50 12±0.5% vs. PLC70/30 15±0.6%; P = 0.91) over a period of 6 months. Histology, immunohistochemistry and immuno-fluorescence also revealed no significant inflammatory reaction from either of the microfilms, which confirmed that both microfilms are biocompatible. The duration of the drug delivery can be tailored by selecting the materials, which have different degradation kinetics, to suit the desired clinical therapeutic application.

Show MeSH
Related in: MedlinePlus