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Effect of 2-hydroxypropyl-beta-cyclodextrin on the ocular absorption of dexamethasone and dexamethasone acetate.
Pharm Res 1991; 8(12):1495-9PR

Abstract

Complexation of dexamethasone (DX) and dexamethasone acetate (DXA) with 2-hydroxypropyl-beta-cyclodextrin (HPCD) was investigated with an ultimate goal of formulating a topical ophthalmic solution of DXA. Aqueous solubility of DX and DXA was markedly increased due to formation of soluble inclusion complexes with HPCD. Based on characterization of complex formation by phase solubility and UV-spectroscopy methods, a stoichiometry of 1:1 and 1:1, 1:2 was assumed for DX-HPCD and DXA-HPCD complexes, respectively. The stability constants for complex formation estimated by phase solubility and UV-spectroscopy methods, respectively, were as follows: for DX-HPCD complex, K1:1 = 2193 and 2221 M-1; and for DXA-HPCD complex, K1:1 = 2240 and 2445 M-1 and K1:2 = 3 and 17 M-1. K1:1 of 2266 M-1 and K1:2 of 20 M-1 were also estimated for the DXA-HPCD complex by kinetics. The kinetics of DXA degradation in pH 7 phosphate buffer at 25 degrees C followed pseudo first order. The addition of HPCD decreased the rate but the order of reaction remained unchanged. Free DXA degraded at a faster rate than complexed DXA. Ocular bioavailability in conjunctiva, cornea, iris, and aqueous humor postadministration of a 25-microliters dose of formulations containing an equivalent of 0.1% (w/v) DX followed a rank-order of DXA-HPCD solution greater than DXA suspension greater than DX-HPCD solution greater than DX suspension.

Authors+Show Affiliations

Division of Pharmaceutics and Medicinal Chemistry, School of Pharmacy, Northeast Louisiana University, Monroe 71209.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

1808612

Citation

Usayapant, A, et al. "Effect of 2-hydroxypropyl-beta-cyclodextrin On the Ocular Absorption of Dexamethasone and Dexamethasone Acetate." Pharmaceutical Research, vol. 8, no. 12, 1991, pp. 1495-9.
Usayapant A, Karara AH, Narurkar MM. Effect of 2-hydroxypropyl-beta-cyclodextrin on the ocular absorption of dexamethasone and dexamethasone acetate. Pharm Res. 1991;8(12):1495-9.
Usayapant, A., Karara, A. H., & Narurkar, M. M. (1991). Effect of 2-hydroxypropyl-beta-cyclodextrin on the ocular absorption of dexamethasone and dexamethasone acetate. Pharmaceutical Research, 8(12), pp. 1495-9.
Usayapant A, Karara AH, Narurkar MM. Effect of 2-hydroxypropyl-beta-cyclodextrin On the Ocular Absorption of Dexamethasone and Dexamethasone Acetate. Pharm Res. 1991;8(12):1495-9. PubMed PMID: 1808612.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effect of 2-hydroxypropyl-beta-cyclodextrin on the ocular absorption of dexamethasone and dexamethasone acetate. AU - Usayapant,A, AU - Karara,A H, AU - Narurkar,M M, PY - 1991/12/1/pubmed PY - 1991/12/1/medline PY - 1991/12/1/entrez SP - 1495 EP - 9 JF - Pharmaceutical research JO - Pharm. Res. VL - 8 IS - 12 N2 - Complexation of dexamethasone (DX) and dexamethasone acetate (DXA) with 2-hydroxypropyl-beta-cyclodextrin (HPCD) was investigated with an ultimate goal of formulating a topical ophthalmic solution of DXA. Aqueous solubility of DX and DXA was markedly increased due to formation of soluble inclusion complexes with HPCD. Based on characterization of complex formation by phase solubility and UV-spectroscopy methods, a stoichiometry of 1:1 and 1:1, 1:2 was assumed for DX-HPCD and DXA-HPCD complexes, respectively. The stability constants for complex formation estimated by phase solubility and UV-spectroscopy methods, respectively, were as follows: for DX-HPCD complex, K1:1 = 2193 and 2221 M-1; and for DXA-HPCD complex, K1:1 = 2240 and 2445 M-1 and K1:2 = 3 and 17 M-1. K1:1 of 2266 M-1 and K1:2 of 20 M-1 were also estimated for the DXA-HPCD complex by kinetics. The kinetics of DXA degradation in pH 7 phosphate buffer at 25 degrees C followed pseudo first order. The addition of HPCD decreased the rate but the order of reaction remained unchanged. Free DXA degraded at a faster rate than complexed DXA. Ocular bioavailability in conjunctiva, cornea, iris, and aqueous humor postadministration of a 25-microliters dose of formulations containing an equivalent of 0.1% (w/v) DX followed a rank-order of DXA-HPCD solution greater than DXA suspension greater than DX-HPCD solution greater than DX suspension. SN - 0724-8741 UR - https://www.unboundmedicine.com/medline/citation/1808612/Effect_of_2_hydroxypropyl_beta_cyclodextrin_on_the_ocular_absorption_of_dexamethasone_and_dexamethasone_acetate_ L2 - http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=1808612.ui DB - PRIME DP - Unbound Medicine ER -