Preparation and evaluation of a time-controlled release capsule made of ethylcellulose for colon delivery of drugs.

Niwa, Kiyoshi; Takaya, Tomohiro; Kondo, Shin‐ichiro; Takeshita, Yoko; Takada, Kanji

doi:10.2745/dds.10.121

Cited by 11 publications

(10 citation statements)

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“…The lag time varied from 1.8 h to 5.8 h with an average value of 3.52 ± 1.73 h and was mainly attributed to individual differences among dogs. Nevertheless, the value was coincident with the average time it takes to reach the colon, which has been estimated by colon-specific delivery capsules to be 3.3 h (Niwa et al, 1995;Takaya et al, 1995). The quick disintegration of the core tablet in the stomach and subsequent dissolution resulted in a comparatively higher concentration of indomethacin in upper gastrointestinal tract.…”

Section: Pharmacokinetics In Beagle Dogsmentioning

confidence: 95%

Anin situcrosslinked compression coat comprised of pectin and calcium chloride for colon-specific delivery of indomethacin

Wei

Lü

et al. 2014

Drug Delivery

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(2015) An insitu crosslinked compression coat comprised of pectin and calcium chloride for colon-specific delivery of indomethacin, Drug Delivery, 22:3, 298-305, DOI: 10.3109/10717544.2013 AbstractThe use of pectin for colon-specific drug delivery has been extensively investigated; however, when used alone, pectin is often compromised due to its high solubility. This study explored the feasibility of using an in situ compression-coated crosslinking system, composed of pectin and calcium chloride, for colon-specific drug delivery. A pectin/calcium chloride (P/Ca) coating was compressed onto a core tablet. The colon specificity of the compression-coated tablet was verified by dissolution, pharmacokinetics and scintigraphy with 99m Tc labeling. The in situ pectin and calcium chloride gel slowed the release of indomethacin. The lag time varied between 3 h and 7 h depending on the amount of calcium chloride and the coating weight. Pectinase triggered the release of indomethacin from the compression-coated tablet, which was then accelerated by the calcium chloride in the coating layer. The compression-coated tablet had a prolonged t max and apparent t 1/2 , as well as a decreased C max and AUC 0-t , compared with the core tablet counterpart. Evaluation with g-scintigraphy verified colonspecific delivery of the compression-coated tablet. In conclusion, the P/Ca in situ crosslinking system worked well for colon-specific drug delivery.

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Section: Pharmacokinetics In Beagle Dogsmentioning

confidence: 95%

Anin situcrosslinked compression coat comprised of pectin and calcium chloride for colon-specific delivery of indomethacin

Wei

Lü

et al. 2014

Drug Delivery

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“…21 The degradable capsule of ethyl cellulose was prepared by coating a parent mold of gelatin, which was later coated with ethyl cellulose with various thicknesses. Upon dissolving gelatin in water, the coating of ethyl cellulose provided a large number of mechanically produced micropores that allowed the diffusion of water in the capsule.…”

Section: Bulk Eroding Systemsmentioning

confidence: 99%

Barrier-Mediated Pulsatile Release

Gandhi

Gosse

Nishii

et al. 2015

Journal of Membrane Science

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ii To my loving wife and wonderful parents.iii ACKNOWLEDGMENTS First and foremost I would like to thank my research advisor Dr. Eric Nuxoll for his support, brilliant advice, professionalism and endless patience. He has been a great mentor throughout my doctoral studies at the University of Iowa since I became his first graduate student. Besides overall research skills, I learned much more including how to address a problem in a practical way, determine priorities and most importantly how to express and defend ideas. I have had the privilege to work with very talented undergrad students Matthew Gosse and Derek Baerenwald, who directly contributed to this project. I am also grateful to Yasuhiro Nishii, a visiting scholar from Japan, for his partial contributions to this work and continued work forward with this project. Guiding and mentoring these bright individuals was an exciting opportunity and also a great experience for me. Others who have helped me along the way include my fellow research group members Ann O'Toole, Joel Coffel, Erica Bader and Bryce Hundley. iv I am incredibly grateful to my parents who have always supported me. I have been blessed to be born in a loving family that has fully encouraged and enabled me to achieve my dreams. Finally, no words can express my thankfulness to Khushbu, my wife, who always stood by me throughout this journey. Without her encouragement and motivation I would not have pursued the education to the length I have.v ABSTRACT Solutes are often most efficiently deployed in discrete pulses, for example in the delivery of herbicides or drugs. Manual application of each pulse can be labor-intensive, automated application of each pulse can be capital intensive, and both are often costly and impractical. Barrier-Mediated Pulsatile Release (BMPR) systems offer a materialsbased alternative for automated pulsatile drug delivery, without pumps, power supplies, or complex circuitry. While earlier materials-based approaches such as delayed-release microcapsules are limited to two or three pulses due to the independent nature of each pulse's timing control, BMPR systems link the timing of each pulse to the previous pulse.Each dose of drug is sequestered in its own stimuli-sensitive depot, releasing only upon contact with the stimulant. These depots are stacked with sacrificial barriers in between, each of which block the stimulant for a predetermined time. For instance, layers of soluble drug may be separated by degradable polymer layers. Water, as the stimulant, will erode the polymer layer over a fixed period of time, followed by quick dissolution and release of the underlying drug and the start of degradation for the next polymer layer.This example, however, is quickly limited by irregular polymer erosion, a single stimulant (water), and difficulty in scaling delay times.The research work presented in this thesis reports the development of a generalized BMPR system which overcomes those limitations. Model drugs (methylene blue and methyl orange) were immobilized in a pH-sensitive ...

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“…Li et al (2008) concluded from the outcome of their research that programmed delivery of the drug can be obtained from the tablets in the capsule system by systemic formulation approach to achieve pulsatile release three times daily. Niwa et al (1995) prepared a novel capsule made from EC for the time-controlled release of drugs in the colon. The EC capsules were prepared by coating the gelatin capsule with EC.…”

Section: Time Controlled Systemmentioning

confidence: 99%