title: A paradigm shift in enteric coating: achieving rapid release in the proximal small intestine of man.
abstract: The in vivo performance of a novel enteric double-coating technology designed to accelerate release in the proximal small intestine of humans was investigated. Tablet cores were coated with a double layer formulation consisting of an inner layer of EUDRAGIT L 30 D-55 neutralised to pH 6.0 in the presence of 10% citric acid, and an outer layer of standard EUDRAGIT L 30 D-55. A conventional single coating of EUDRAGIT L 30 D-55 was also applied to tablets for comparison purposes, with the identical coating formulation and thickness (5mg/cm(2)) as the outer layer of the double coating. Eight fasted volunteers received the double-coated and single-coated tablets in a two-way crossover study. The formulations were radiolabelled and followed by gamma scintigraphy; the disintegration times and positions were recorded. After leaving the stomach, tablets coated with the single-coating formulation showed a significant time delay before disintegration occurred in the mid to distal small intestine, with a mean disintegration time of 66 ± 22 min post gastric emptying. The double-coated tablets disintegrated earlier at 28 ± 6min post gastric emptying with consistent disintegration in the proximal small intestine. The accelerated in vivo disintegration of the double-coating system can overcome the limitations of conventional enteric coatings.
authors.affiliation: Department of Pharmaceutics, The School of Pharmacy, University of London, 29/39 Brunswick Square, London WC1N 1AX, UK.
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.forename: Abdul W
authors.initials: AW
authors.lastname: Basit
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D004337:Drug Carriers / Q000737:chemistry; D004339:Drug Compounding; D005746:Gastric Emptying; D006801:Humans; D007421:Intestine, Small / Q000000981:diagnostic imaging / Q000378:metabolism*; D008297:Male; D008689:Methacrylates / Q000737:chemistry; D011108:Polymers; D011868:Radioisotopes; D011877:Radionuclide Imaging; D012995:Solubility; D013608:Tablets, Enteric-Coated / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics; D013997:Time Factors; D055815:Young Adult
chemical_list: D004337:Drug Carriers; C477852:Eudragit L 30 D-55; D008689:Methacrylates; D011108:Polymers; D011868:Radioisotopes; D013608:Tablets, Enteric-Coated