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Slow-release characteristics of diltiazem from ethylated beta-cyclodextrin complexes
Y Horiuchi1, F Hirayama, K Uekama
1Faculty of Pharmaceutical Sciences, Kumamoto University, Japan.
Journal of Pharmaceutical Sciences
|February 1, 1990
Summary
Ethylated beta-cyclodextrins, like diethyl-beta-cyclodextrin, effectively create sustained-release drug delivery systems. These cyclodextrin complexes significantly slow diltiazem hydrochloride release, enhancing drug efficacy.
Area of Science:
- Pharmaceutical Sciences
- Drug Delivery Systems
- Polymer Chemistry
Background:
- Beta-cyclodextrins are cyclic oligosaccharides used in drug formulations.
- Ethylated beta-cyclodextrins offer modified properties for drug delivery.
- Diltiazem hydrochloride is a widely used calcium channel blocker.
Purpose of the Study:
- To evaluate ethylated beta-cyclodextrins as sustained-release carriers for diltiazem hydrochloride.
- To investigate the influence of environmental factors on drug release kinetics.
- To understand the release mechanism from cyclodextrin-based matrices.
Main Methods:
- Complexation of diltiazem hydrochloride with diethyl-beta-cyclodextrin and triethyl-beta-cyclodextrin.
- Dissolution testing of compressed tablets under various conditions (pH, stirring speed, additives).
- Microscopic analysis of tablet surfaces and measurement of water penetration rates.
- In vivo pharmacokinetic study in dogs following oral administration.
Main Results:
- Complexation with ethylated beta-cyclodextrins significantly retarded diltiazem hydrochloride release.
- Drug release was influenced by pH, rotating speed, and dissolution medium additives.
- A hydrophobic matrix formed by diethyl-beta-cyclodextrin facilitated slow drug release post-water penetration.
- Oral administration in dogs demonstrated a prolonged sustained-release profile without affecting the total drug exposure (AUC).
- Mixing ethylated beta-cyclodextrin complexes with parent beta-cyclodextrin allowed for tunable release rates.
Conclusions:
- Ethylated beta-cyclodextrins, particularly diethyl-beta-cyclodextrin, are effective matrices for developing sustained-release formulations of diltiazem hydrochloride.
- The release mechanism involves water penetration into a hydrophobic cyclodextrin matrix.
- Drug release kinetics can be modulated by formulation composition and environmental factors.
- These cyclodextrin-based systems offer a promising approach for achieving long-term therapeutic drug levels.