Cross-linked beta-cyclodextrin microcapsules. II. Retarding effect on drug release through semi-permeable membranes.
Microcapsules were prepared by interfacial cross-linking of beta-cyclodextrins (beta-CD) with terephthaloylchloride (TC) as described previously. Complexation assays were conducted with propranolol HCl. After 1 h incubation of 50 mg lyophilized microcapsules in 10 ml propranolol solution, the amounts of fixed drug were 507.5+/-8.6 micromol and 811.2+/-16.0 micromol per g lyophilized microcapsules with 1 mM and 2 mM solutions, respectively. A dialysis experiment was then performed. After 1 h incubation of microcapsules (10 or 50 mg) in 10 ml of 2 mM propranolol solution, the suspension was dialysed against a phosphate buffer pH 7.4 at 37 degrees C. The drug diffusion was all the more retarded that the amount of added beta-CD microcapsules was higher. Finally, double microcapsules were prepared using a suspension of beta-CD microcapsules (10-100 mg) in a solution of methylene blue in an acetate buffer pH 7.4. After adding human serum albumin (HSA), the suspension was emulsified in cyclohexane and double microcapsules were obtained by cross-linking the HSA with TC. In vitro release studies showed that the incorporation of beta-CD microcapsules resulted in a decrease in release rate of methylene blue, the decrease being related to the amount of encapsulated beta-CD microcapsules. The study then suggests interesting applications of beta-CD microcapsules for modulating the release rate of drugs through semi-permeable membranes.
Pariot
N
N
Laboratoire de Pharmacotechnie, UMR/CNRS 6013, IFR 53, Faculté de Pharmacie, Université de Reims, 51 Rue Cognacq-Jay, F-51096 Cedex, Reims, France.
Edwards-Lévy
F
F
Andry
M-C
MC
Lévy
M-C
MC
D000959:Antihypertensive Agents / Q000737:chemistry*; D002214:Capsules; D002626:Chemistry, Pharmaceutical; D003505:Cyclodextrins / Q000737:chemistry*; D005503:Food Additives / Q000737:chemistry*; D008567:Membranes, Artificial; D011433:Propranolol / Q000737:chemistry*; D047392:beta-Cyclodextrins
D000959:Antihypertensive Agents; D002214:Capsules; D003505:Cyclodextrins; D005503:Food Additives; D008567:Membranes, Artificial; D047392:beta-Cyclodextrins; D011433:Propranolol; C031215:betadex