Preparation and in vitro evaluation of a novel combined multiparticulate delayed-onset sustained-release formulation of diltiazem hydrochloride
A combined delivery system, containing two kinds of diltiazem hydrochloride multi-layer coated pellets with different release characteristics, was developed to meet chronotherapeutic requirements. The dissolution studies in vitro indicated that the combined system could constantly
release drug at a predetermined time in synchrony with the biologic rhythm of disease activity. These two kinds of pellets were mixed at the ratio 1 : 1. Pellet 2 could provide drug during the later phase of drug release from pellet 1, because the amount released was insufficient in the later
phase (about 14–24 h after administration) for pellet 1. Addition of Tween 20 in the HPMC swelling layer was able to modify the hydration rate of HPMC layer which controlled the delayed time of the release system. It was found that the drug release kinetics followed Hixson-Crowell equation
and this indicated that the main drug-transport mechanism inside the pellets was an erosion mechanism. The drug release rate was independent of the hydrodynamic conditions and pH of the external environment, and showed a decrease with increasing of osmotic pressure of the dissolution medium.
These release characteristics indicated that the drug release from this system was driven by osmotic-pressure gradient.
Document Type: Research Article
Affiliations: 1: Department of Pharmaceutics, China Pharmaceutical University, Nanjing, P.R. China 2: Department of Pharmaceutics, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing, 210009, P.R. China, Email: [email protected]
Publication date: 01 December 2007
- Pharmazie is a leading journal in the field of pharmaceutical sciences. As a peer-reviewed scientific journal, Pharmazie is regularly indexed in the relevant databases like Web of science, Journal Citation Reports and many others. The journal is open for submissions from the whole spectrum of pharnaceutical sciences including Pharmaceutical Chemistry, Experimental and Clinical Pharmacology, Drug Analysis, Pharmaceutics, Pharmaceutical Biology, Clinical Pharmacy etc.
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