A technique for saturation of bioresorbable drainages with dexamethasone to prevent excessive scarring in the surgical treatment of glaucoma

Background: drainage saturated with antiproliferative substances is one of promising strategies to prevent excessive scarring in glaucoma surgery. Glucocorticosteroids (in particular, dexamethasone) are the safest and the most efficient representatives of the drugs. To achieve a target result, a surgical site should be exposed to this drug for a long time. Aim: to develop a technique for saturation of an antiglaucomatous drainage with dexamethasone suspension ex tempore to provide extended release of the drug substance at therapeutic concentrations in vitro. Materials and Methods: a bioresorbable drainage made of poly(D,L-lactide-co-glycolide) with a pore size of 5–50 μm (biodegradation period: ≤8 months) was used as a substrate for saturation with dexamethasone. To saturate the drainages, they were placed in 0.1% dexamethasone powder suspension in saline solution and ultrasonicated. Two modes of ultrasonication were used in the test. To be saturated, samples 1 (3 pcs) were ultrasonicated (power — 100 W, frequency –22 kHz) for 6 minutes. Samples 2 (3 pcs) were exposed to ultrasound (power — 20 W, frequency — 30 kHz) for 15 minutes. After ultrasonication, the drainages were removed from the suspension, squeezed, dried, and then weighed to determine weight gain. For both groups, the minimum drainage saturation time was set when weight gain was not reported. To determine a profile of dexamethasone release from the drainages under close-to-real conditions, the samples saturated with dexamethasone by the abovementioned method (3 pcs each) were kept in glass vials with balanced salt solution (BSS) at 37 °C for one month. Every day the drainages were transferred to a new BSS whose volume was calculated by reference to volume of intraocular fluid passing through a filtering bleb within a predetermined period of time (i.e., 3 ml/day). Dexamethasone level in the washing solutions was determined by spectrophotometry. Results: low-power high-frequency ultrasound (20 W, 30 kHz, 15 minutes) resulted in a significant increase in sorbed dexamethasone amount which ensured maintenance of therapeutic concentrations within 26 days (i. e., the most critical period for inflammation and proliferative processes). Conclusions: a bioresorbable antiglaucomatous drainage tube made of poly(D,L-lactide-co-glycolide) saturated with dexamethasone by the developed technique may be used as a safe and an efficient strategy to manage postoperative scarring in the surgical treatment of glaucoma. KEYWORDS: glaucoma, excessive scarring, antiproliferative drugs, antiglaucoma drain, surgical treatment. FOR CITATION: Radaykina M.V., Zolotarev A.V., Karlova E.V., Glubokova M.N. A technique for saturation of bioresorbable drainages with dexamethasone to prevent excessive scarring in the surgical treatment of glaucoma. Russian Journal of Clinical Ophthalmology. 2025;25(4):238–242 (in Russ.). DOI: 10.32364/2311-7729-2025-25-4-2