Direct Compression Controlled Release Tablets Using Ethylcellulose Matrices

Upadrashta, Sathyanarayana M.; Katikaneni, Pruthvipathy R.; Hileman, Gregory A.; Keshary, Prakash R.

doi:10.3109/03639049309063202

Cited by 40 publications

(22 citation statements)

References 10 publications

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“…[11][12][13][14] Several reports have directly addressed the use of EC as a directly compressible excipient in a controlled-release matrix or in an immediaterelease tablet. [15][16][17] In our previous studies, EC powder with different micronized sizes has been directly compressed to form compact EC in which plastic deformation is the predominant consolidation mechanism. 18 Furthermore, the particle size of EC powder and the porosity in compact EC are the major factors that influence the uptake of water and the dissolution of drug from the compacted form.…”

Section: Introductionmentioning

confidence: 99%

Hydrophilic excipients modulate the time lag of time-controlled disintegrating press-coated tablets

Lin

2004

AAPS PharmSciTech

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An oral press-coated tablet was developed by means of direct compression to achieve the time-controlled disintegrating or rupturing function with a distinct predetermined lag time. This press-coated tablet containing sodium diclofenac in the inner core was formulated with an outer shell by different weight ratios of hydrophobic polymer of micronized ethylcellulose (EC) powder and hydrophilic excipients such as spray-dried lactose (SDL) or hydroxypropyl methylcellulose (HPMC). The effect of the formulation of an outer shell comprising both hydrophobic polymer and hydrophilic excipients on the time lag of drug release was investigated. The release profile of the press-coated tablet exhibited a time period without drug release (time lag) followed by a rapid and complete release phase, in which the outer shell ruptured or broke into 2 halves. The lag phase was markedly dependent on the weight ratios of EC/SDL or EC/HPMC in the outer shell. Different time lags of the press-coated tablets from 1.0 to 16.3 hours could be modulated by changing the type and amount of the excipients. A semilogarithmic plot of the time lag of the tablet against the weight ratios of EC/SDL or EC/HPMC in the outer shell demonstrated a good linear relationship, with r = 0.976 and r = 0.982, respectively. The predetermined time lag prior to the drug release from a presscoated tablet prepared by using a micronized EC as a retarding coating shell can be adequately scheduled with the addition of hydrophilic excipients according to the time or site requirements.

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Section: Introductionmentioning

confidence: 99%

Hydrophilic excipients modulate the time lag of time-controlled disintegrating press-coated tablets

Lin

2004

AAPS PharmSciTech

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“…However, the blood level is maintained at steady state as the drug is released from the sustaining granules. Among the different polymers, Eudragit (5,6) and ethylcellulose (7)(8)(9)(10)(11) have been used successfully to obtain appropriate sustained release matrix formulations of different materials. The present study aims at formulating bilayered tablets of propranolol hydrochloride with a fast release layer using sodium starch glycolate and a sustaining layer using hydrophobic polymers like ethylcellulose, Eudragit RLPO and Eudragit RSPO.…”

mentioning

confidence: 99%

Design and evaluation of sustained release bilayer tablets of propranolol hydrochloride

Patra¹,

Kumar²,

Pandit³

et al. 2007

Acta Pharmaceutica

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“…For water-soluble drugs, simple diffusion appears to be the mechanism of drug release from an EC matrix tablet, as with pseudoephedrine hydrochloride at 12.5-25% drug loading, in which the data are described by the Higuchi equation (50). Meanwhile, the release of slightly soluble theophylline or practically insoluble indomethacin at 50% or 25% drug loading, respectively, occurs by diffusion with polymer relaxation and erosion contributions (46). Pather et al also investigated an EC matrix tablet containing theophylline in which a release profile resembling the zero-order model has been reported (49).…”

Section: Non-lipid Based Matricesmentioning

confidence: 97%

“…Tablet hardness has a stronger impact on the dissolution half-life than viscosity grade. Lower viscosity grades induce more compressible dosage forms, allowing for a wider range of tablet hardness and, thus, of dissolution rates (46). Among the various viscosity grades of EC, a 10 cps viscosity grade is highly compressible and produces a harder tablet (47).…”

Section: Non-lipid Based Matricesmentioning

confidence: 99%

Controlled Release Systems Containing Solid Dispersions: Strategies and Mechanisms

et al. 2011

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In addition to a number of highly soluble drugs, most new chemical entities under development are poorly water-soluble drugs generally characterized by an insufficient dissolution rate and a small absorption window, leading to the low bioavailability. Controlled-release (CR) formulations have several potential advantages over conventional dosage forms, such as providing a uniform and prolonged therapeutic effect to improve patient compliance, reducing the frequency of dosing, minimizing the number of side effects, and reducing the strength of the required dose while increasing the effectiveness of the drug. Solid dispersions (SD) can be used to enhance the dissolution rate of poorly water-soluble drugs and to sustain the drug release by choosing an appropriate carrier. Thus, a CR-SD comprises both functions of SD and CR for poorly water-soluble drugs. Such CR dosage forms containing SD provide an immediately available dose for an immediate action followed by a gradual and continuous release of subsequent doses to maintain the plasma concentration of poorly water-soluble drugs over an extended period of time. This review aims to summarize all currently known aspects of controlled release systems containing solid dispersions, focusing on the preparation methods, mechanisms of action and characterization of physicochemical properties of the system.

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Direct Compression Controlled Release Tablets Using Ethylcellulose Matrices

Cited by 40 publications

References 10 publications

Hydrophilic excipients modulate the time lag of time-controlled disintegrating press-coated tablets

Hydrophilic excipients modulate the time lag of time-controlled disintegrating press-coated tablets

Design and evaluation of sustained release bilayer tablets of propranolol hydrochloride

Controlled Release Systems Containing Solid Dispersions: Strategies and Mechanisms

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