TY - JOUR

T1 - Synthesis and characterization of novel succinyl chitosan-dexamethasone conjugates for potential intravitreal dexamethasone delivery

AU - Dubashynskaya, Natallia V.

AU - Bokatyi, Anton N.

AU - Golovkin, Alexey S.

AU - Kudryavtsev, Igor V.

AU - Serebryakova, Maria K.

AU - Trulioff, Andrey S.

AU - Dubrovskii, Yaroslav A.

AU - Skorik, Yury A.

N1 - Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2021/10/1

Y1 - 2021/10/1

N2 - The development of intravitreal glucocorticoid delivery systems is a current global chal-lenge for the treatment of inflammatory diseases of the posterior segment of the eye. The main ad-vantages of these systems are that they can overcome anatomical and physiological ophthalmic barriers and increase local bioavailability while prolonging and controlling drug release over several months to improve the safety and effectiveness of glucocorticoid therapy. One approach to the development of optimal delivery systems for intravitreal injections is the conjugation of low-molecu-lar-weight drugs with natural polymers to prevent their rapid elimination and provide targeted and controlled release. This study focuses on the development of a procedure for a two-step synthesis of dexamethasone (DEX) conjugates based on the natural polysaccharide chitosan (CS). We first used carbodiimide chemistry to conjugate DEX to CS via a succinyl linker, and we then modified the obtained systems with succinic anhydride to impart a negative ζ-potential to the polymer particle surface. The resulting polysaccharide carriers had a degree of substitution with DEX moieties of 2–4%, a DEX content of 50–85 μg/mg, and a degree of succinylation of 64–68%. The size of the obtained particles was 400–1100 nm, and the ζ-potential was −30 to −33 mV. In vitro release studies at pH 7.4 showed slow hydrolysis of the amide and ester bonds in the synthesized systems, with a total release of 8–10% for both DEX and succinyl dexamethasone (SucDEX) after 1 month. The de-veloped conjugates showed a significant anti-inflammatory effect in TNFα-induced and LPS-in-duced inflammation models, suppressing CD54 expression in THP-1 cells by 2-and 4-fold, respec-tively. Thus, these novel succinyl chitosan-dexamethasone (SucCS-DEX) conjugates are promising ophthalmic carriers for intravitreal delivery.

AB - The development of intravitreal glucocorticoid delivery systems is a current global chal-lenge for the treatment of inflammatory diseases of the posterior segment of the eye. The main ad-vantages of these systems are that they can overcome anatomical and physiological ophthalmic barriers and increase local bioavailability while prolonging and controlling drug release over several months to improve the safety and effectiveness of glucocorticoid therapy. One approach to the development of optimal delivery systems for intravitreal injections is the conjugation of low-molecu-lar-weight drugs with natural polymers to prevent their rapid elimination and provide targeted and controlled release. This study focuses on the development of a procedure for a two-step synthesis of dexamethasone (DEX) conjugates based on the natural polysaccharide chitosan (CS). We first used carbodiimide chemistry to conjugate DEX to CS via a succinyl linker, and we then modified the obtained systems with succinic anhydride to impart a negative ζ-potential to the polymer particle surface. The resulting polysaccharide carriers had a degree of substitution with DEX moieties of 2–4%, a DEX content of 50–85 μg/mg, and a degree of succinylation of 64–68%. The size of the obtained particles was 400–1100 nm, and the ζ-potential was −30 to −33 mV. In vitro release studies at pH 7.4 showed slow hydrolysis of the amide and ester bonds in the synthesized systems, with a total release of 8–10% for both DEX and succinyl dexamethasone (SucDEX) after 1 month. The de-veloped conjugates showed a significant anti-inflammatory effect in TNFα-induced and LPS-in-duced inflammation models, suppressing CD54 expression in THP-1 cells by 2-and 4-fold, respec-tively. Thus, these novel succinyl chitosan-dexamethasone (SucCS-DEX) conjugates are promising ophthalmic carriers for intravitreal delivery.

KW - Anti-inflammatory activity

KW - Dexamethasone

KW - Intravitreal delivery systems

KW - Succinyl chitosan

UR - http://www.scopus.com/inward/record.url?scp=85116686842&partnerID=8YFLogxK

U2 - 10.3390/ijms222010960

DO - 10.3390/ijms222010960

M3 - Article

C2 - 34681619

AN - SCOPUS:85116686842

VL - 22

JO - International Journal of Molecular Sciences

JF - International Journal of Molecular Sciences

SN - 1422-0067

IS - 20

M1 - 10960

ER -