Examination of drug solubility, polymer types, hydrodynamics and loading dose on drug release behavior from a triple-layer asymmetric configuration delivery system

Yang, Libo; Fassihi, Reza

doi:10.1016/s0378-5173(97)00164-6

Cited by 60 publications

(30 citation statements)

References 27 publications

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“…To predict the mechanism of diffusional release, the following semiempirical equation of was used to analyze the data of controlled-release of this water soluble drug from the studied polymer matrices (Peppas 1985;Yang and Fassihi 1997). In this equation, Mt is amount of the released drug at time t, M∞ is the overall amount of the drug (whole dose), k is the constant incorporating structural and geometric characteristics of the controlled-release device, and n is the release exponent indicative of the drug release mechanism.…”

Section: Discussionmentioning

confidence: 99%

Formulation and evaluation of glipizide floating-bioadhesive tablets

Patel¹,

Chavda

2010

Braz. arch. biol. technol.

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Section: Discussionmentioning

confidence: 99%

Formulation and evaluation of glipizide floating-bioadhesive tablets

Patel¹,

Chavda

2010

Braz. arch. biol. technol.

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“…The varying loading dose of diltiazem HCl in three-layer tablets (prepared using polyethylene oxide combined with HPMC K4M) did not affect the drug release behavior (8). However, an increase in stirring rate during dissolution of those systems enhanced the drug release rate with the linearity of release profiles remained unaltered.…”

Section: Introductionmentioning

confidence: 92%

“…The coated layers were designed to initially delay the hydration rate of the middle layer. The external layers would disappear gradually at disproportionate rates, creating more surface area for drug diffusion, thus there was the counterbalancing of the reduction of diffusing surface area due to the erosion as well as the increase in diffusional path-length due to continuous system swelling (8).…”

Section: In Vitro Drug Release From the Prepared Tabletsmentioning

confidence: 99%

Variables Influencing Drug Release from Layered Matrix System Comprising Hydroxypropyl Methylcellulose

Phaechamud

2008

AAPS PharmSciTech

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Abstract. The purpose of this study was to prepare and evaluate layered matrix tablets of propranolol HCl containing HPMC and phytowax as matrix component using direct compression technique. Layering with this polymeric matrix could prolong the release of drug and shift the release pattern approach to zero order as described from the least square curve fitting. Increasing the amount of coating layer could apparently prolong the drug release. The longer lag time of drug release from one planar apparently when the amount of coating layer was increased. HPMC concentration and compression force did not affect the drug release from this three-layer tablet. The drug release from this three-layer tablet was influenced by hydrodynamic force. An increase in stirring rate was a corresponding increasing in the release rate. From photoimage and SEM, gel mass of HPMC was increased with time during dissolution and covered the core surface, therefore dissolved drug molecules were allowed to diffuse out from the core through the polymer network of gel layer containing the porous structure. This suggested that HPMC and phytowax could be fabricated into the layered matrix tablet exhibiting sustained drug release.

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“…Variations in hydrodynamic conditions recommended by specified stirring speed, namely 50 rpm, 100 rpm, and/or 150 rpm for the paddle method may provide valuable insight into system performance. 17) In some cases, low hydrodynamic intensity have shown to mimic in vivo situation more closely. 18,19) Changes in paddle speed or agitation intensity during the in vitro dissolution study might be a simple indicator of the environmental effect on the release rate.…”

Section: Effect Of Various Hydrodynamic Conditions and Ionicmentioning

confidence: 99%

Formulation Variation and in Vitro-in Vivo Correlation for a Rapidly Swellable Three-Layered Tablet of Tamsulosin HCl

Park

Shim

Park

et al. 2011

CHEMICAL & PHARMACEUTICAL BULLETIN

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Regular ArticleA novel three-layered tablet technology consisting of an inner immediate release layer and two extended release barrier layers with swellable polymers has been suggested and investigated as once-a-day tablet formulations. 1) In that formulation, dissolution medium quickly permeates to the inner layer of water-soluble excipients, and the two barrier layers swell to surround the inner layer rapidly, controlling drug release from the inner layer. After oral administration, the tablet might become fully hydrated quickly and reach the colon where little water is available. The hydrated state of the tablet might induce continuous drug release even in the colon.As an extended study on the technology and to investigate the feasibility as a once-a-day tablet formulation, a hydrophilic model drug (tamsulosin HCl) was selected and various three-layered tablet formulations were evaluated together with their properties. These formulations were also compared with a commercial product, tamsulosin OCAS ® , to achieve more consistent plasma drug concentrations. Additionally, a pharmacokinetic study of the three-layered tablets using beagle dogs was performed in comparison with the results of the reference tablet.Tamsulosin Fig. 1), is a third-generation a1-adrenoceptor (AR) antagonist and has been developed for the treatment of lower urinary tract symptoms suggestive of benign prostatic hyperplasia (LUTS/BPH). 2) Among the currently available a1-AR antagonists, tamsulosin is the most frequently prescribed pharmacological therapy due to its favorable selectivity for human prostatic tissue, which is probably related to the a1 A and a1 D -AR subtypes. 3,4) Tamsulosin HCl modified-release (MR) capsules are developed by Astellas Pharma Inc., and marketed under the trade names Harnal, Flomax, Flomaxtra, and Urimax. On the other hand, generic non-modified release capsules are still approved and marketed in many countries such as Canada and the U.S. The tamsulosin MR capsule formulations, however, have some limitations such as food dependent absorption.3) The labeling information recommends that the capsule needs to be taken after breakfast or after the first meal of the day. Lack of compliance with this dosing recommendation may cause increased exposure to the drug, leading to a higher risk of vasodilatation-related adverse effects like dizziness, headache, orthostatic hypotension, and syncope. 5) To reduce the occurrence of the adverse effects, new oral controlled absorption systems have been developed and used to overcome the low absorption properties even from the colon. 6) The OCAS ® formulation is a controlled release system of a gel matrix type, with gel-forming and gel-enhancing components. Polyethylene glycol (PEG), a gel-enhancing agent, is a hydrophilic agent that facilitates water uptake into the tablets. It may ensure very rapid and nearly complete gelation/hydration of a hydrophilic gel-forming agent (i.e., polyethylene oxide (PEO)) in the upper part of the gastrointestinal (GI) tract, stomach, and small int...

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Examination of drug solubility, polymer types, hydrodynamics and loading dose on drug release behavior from a triple-layer asymmetric configuration delivery system

Cited by 60 publications

References 27 publications

Formulation and evaluation of glipizide floating-bioadhesive tablets

Formulation and evaluation of glipizide floating-bioadhesive tablets

Variables Influencing Drug Release from Layered Matrix System Comprising Hydroxypropyl Methylcellulose

Formulation Variation and in Vitro-in Vivo Correlation for a Rapidly Swellable Three-Layered Tablet of Tamsulosin HCl

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