Pharmaceutical Technology: Controlled Drug Release, Volume 2

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CH. 7] A NEW IBUPROFEN PULSED RELEASE ORAL DOSAGE FORM 83 Fig. 1—Schematic representation of the prepared pulsed release system: a, layer containing the immediately available dose of drug (first dose); b, barrier of swellable polymeric material; c, layer containing the second dose of drug; d impermeable film container. (iv) the dissolution rate of the remaining dose. In vivo experiments A preliminary study involving two healthy adult volunteers was carried out. Each subject received a single oral administration of the following dosage forms: (a) conventional marketed plain tablets (300 mg of Ibuprofen); (b) Conventional plain tablets prepared with granulate A (300 mg of Ibuprofen); two preparations differing in particle size distribution of the active principle; (c) pulsed release system (2×300 mg of Ibuprofen). Collection of blood samples (10 ml) was effected over 12 h following dosing. Plasma was separated by centrifugation and stored at −20°C until analysed. ibuprofen concentration was determined by HPLC using the method described in ref. 14. RESULTS AND DISCUSSION The system prepared is presented in Fig. 1. Structural characteristics of the systems In vitro testing The system works as follows: on contact with the dissolution medium, the uncoated layer (a) rapidly disintegrates, leaving the remaining part of the system intact. The dissolution medium will then come into contact with the barrier (b), slowly interacting with it. The barrier delays the interaction between the dissolution medium and the second dose layer (c) for a time depending on its composition and thickness. As a result of medium-polymer interaction, the barrier slowly becomes viscous and its mechanical resistance decreases. When a sufficient amount of water crosses the barrier, the disintegrants present in layer c swell, thus developing a disintegrating
84 MATRIX FORMULATIONS [CH. 7 Fig. 2—Dissolution profile of the first dose of ibuprofen (pH 7.2 phosphate buffer, 37°C, mean of six replicates). Fig. 3—Dissolution profile of the second dose of ibuprofen (pH 7.2 phosphate buffer, 37°C, mean of six replicates). force. The barrier breaks and the disintegration of the third layer containing the second dose of ibuprofen occurs. The disintegrating force developed by the two doses of the drug on contact with aqueous fluids is the energy source for the delivery of active substance; it has been obtained using superdisintegrants (e.g. Polyplasdone XL ® , Primojel ® ). On in vitro testing when the pulsed release system is immersed in the dissolution medium, the following can be observed: (a) rapid disintegration of the uncoated part of the system (
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PHARMACEUTICAL TECHNOLOGY Controlle
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3 TABLET MACHINE INSTRUMENTATION IN
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First published in 1991 by ELLIS HO
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7 10 Controlled delivery of theophy
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Slow and steady wins the race Poems
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1 Influence of drug solubility in t
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CH. 1] INFLUENCE OF DRUG SOLUBILITY
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24 MATRIX FORMULATIONS [CH. 2 MATER
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26 MATRIX FORMULATIONS [CH. 2 Fig.
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28 MATRIX FORMULATIONS [CH. 2 Table
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30 MATRIX FORMULATIONS [CH. 2 The e
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134 CH. 12] BIODEGRADABLE POLYMERS
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142 CH. 13] A COMPARISON OF DISSOLU
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156 OPHTHALMIC FORMULATION [CH. 14
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162 CH. 15] A SUSTAINED RELEASE OPH
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172 IMPLANTS [CH. 16 The purpose of
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174 IMPLANTS [CH. 16 times with 5 m
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176 IMPLANTS [CH. 16 noted that the
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178 IMPLANTS [CH. 16 Fig. 1—The e
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180 IMPLANTS [CH. 16 Table 3—Tobr
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184 CH. 17] SILICON MATRIX SYSTEMS
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194 INDEX dry granulation, 43 elect
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Pharmaceutical Technology: Controlled Drug Release, Volume 2

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