Abstract
Purpose :
This study investigated the potential of using poly(ethylene glycol) diacrylate (PEGDA) and poly(lactic-co-glycolic acid) (PLGA) based preformed photocrosslinked implants (PPcI) for sustained delivery of a small molecule, triamcinolone acetonide (TA).
Methods :
Gels were formulated by mixing PEGDA, PLGA, photoinitiator and TA at room temperature. PPcI implants were formed by casting the gels into moulds followed by exposure to photocrosslinking at 365 nm for selected time period. The formulations were tested for the effect of lamp intensity (LI) (50 & 100 %), PLGA content (2.5 & 5% w/w), pore forming agent (MgCO3) & PEGDA (6000 Da and 700 Da) molecular weight (Mw) on sustained release of TA. Prepared implants were characterized for surface morphology viascanning electron microscopy (SEM) and in vitro release in phosphate buffer saline (PBS) at pH 7.4, 37°C & 40 rpm in horizontal shaking incubator. TA release was quantified using a validated HPLC-UV method.
Results :
The PPcI implants formed had non-porous smooth surface as observed under SEM. At a LI of 100% and 50% the PPcI showed a mean release of 62% and 74% in 35 days, respectively (Figure 1A). Increasing the PLGA content from 2.5 to 5% w/w increased the release of TA from 46% to 52% in 14 days. Furthermore, to improve the release of TA, a pore forming agent (MgCO3) was used which further increased TA release. On the other hand, high Mw PEGDA showed significantly higher burst release (~70%) compared to low Mw PEGDA which showed ~5% burst release (Figure 1B), however, sustained release was achieved for over 60 days.
Conclusions :
In conclusion, the novel biodegradable PPcI can provide sustained drug release profiles for 2-9 months. Formulation and fabrication variables enable tailored release profiles. The PPcI implants provide the potential for sustained intraocular delivery of drug molecules in treating both front and back of the eye diseases.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.