title: An investigation into the stabilization of diltiazem HCl release from matrices made from aged polyox powders.
abstract: Matrices containing PEO fail to provide stable drug release profiles when stored at elevated temperatures for a period of time. The present study aims to stabilize diltiazem HCl release from matrices made from various molecular weights of polyox powders. To this end, various molecular weights of polyox with and without vitamin E (0.25, 0.5 and 1% w/w) were stored at 40°C for 0, 2, 4 and 8 weeks. The aged polyox powders were then mixed with the model drug at a ratio of 1:1 and compressed into tablets. At different time intervals, the aged polyox with vitamin E were taken out of oven and mixed with the drug (1:1 ratio) and compressed into tablets. Dissolution studies showed a significant increase in diltiazem HCl release rate to occur with increased storage time at 40°C ± 1 from tablets made from the aged polyox (no vitamin E). This was as a result of depolymerization of the aged polyox powders as compared to the fresh polyox samples. This was confirmed by differential scanning calorimetry (DSC) which showed a reduction in the melting point of the aged samples. Concentrations of vitamin E as low as 0.25% w/w was able to overcome the quick release of drug from the matrices made from aged polyox powders. DSC traces showed that the melting point of aged polyox samples containing vitamin E remained the same as that of the fresh samples. The presence of vitamin E is essential to stabilize the drug release from polyox matrices containing diltiazem HCl.
authors.affiliation: Chemistry and Drug Delivery Group, Medway School of Pharmacy, University of Kent, Kent, UK.
authors.forename: Saeed
authors.initials: S
authors.lastname: Shojaee
authors.forename: Kofi
authors.initials: K
authors.lastname: Asare-Addo
authors.forename: Waseem
authors.initials: W
authors.lastname: Kaialy
authors.forename: Ali
authors.initials: A
authors.lastname: Nokhodchi
authors.forename: Iain
authors.initials: I
authors.lastname: Cumming
mesh_terms: D002121:Calcium Channel Blockers / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D004110:Diltiazem / Q000737:chemistry*; D004355:Drug Stability; D007700:Kinetics; D011092:Polyethylene Glycols / Q000737:chemistry*; D011208:Powders; D012995:Solubility; D013607:Tablets; D014810:Vitamin E / Q000737:chemistry / Q000493:pharmacokinetics
chemical_list: D002121:Calcium Channel Blockers; D011208:Powders; D013607:Tablets; D014810:Vitamin E; D011092:Polyethylene Glycols; D004110:Diltiazem
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