Abstract
Purpose:
Intravitreal drugs injection is effective therapy for many posterior segment ocular disorders. However, the short half-lives of the drugs requires repeated injections to maintain their therapeutic effect. In the therapy, there are a high risk of complications and high-cost medical expenses for patients. Therefore, an effective drug delivery method will contribute the advanced treatment. In this study, we evaluate in vitro a self-assembling peptide gel for a potential controlled release drug carrier.
Methods:
100µl (1.25mg) of bevacizumab diluted to 12.5mg/ml was mixed to 200µl of the self-assembling peptide gel (final concentration of gel; 0.05, 0.1, 0.3, 0.5, 0.7 and 1.0%). After the gel-mixtures were stood for 1 hour at RT, 1ml of the distilled water was loaded on the mixtures carefully. After 10 minutes, the whole distilled water was collected and bevacizumab in the water was quantified by the ELISA (entrapment efficacy). Next, 1ml of balanced salt solution (BSS) was loaded on 0.05, 0.1 and 0.3% gel-mixtures. 500µl of the supernatant was collected and replaced with same volume of fresh BSS at frequent time points. Bevacizumab in the collected BSS was quantified (controlled release).
Results:
Bevacizumab entrapment efficacy was over 99%. In 0.05, 0.1% gel-mixtures, the average daily controlled release amount was 0.5µg and 1.3µg. Based on the initial 1.25mg bevacizumab, the each period up to the total amount of drug release was calculated 7 years and 2.5 years. In 0.3% gel-mixture, bevacizumab was not released from the gel.
Conclusions:
All combinations of self-assembling peptide gel concentration and bevacizumab were marked over 99% entrapment efficacy. Then controlled release of bevacizumab was confirmed in the 0.05% and 0.1% self-assembling peptide gel.
Keywords: 748 vascular endothelial growth factor •
412 age-related macular degeneration •
609 neovascularization