In vitro and in vivo evaluation of an oral system for time and/or site-specific drug delivery

Sangalli, M.E.; Maroni, Alessandra; Busetti, C.; Giordano, F.; Gazzaniga, A.

doi:10.1016/s0168-3659(01)00291-7

Cited by 133 publications

(67 citation statements)

References 13 publications

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“…In order to achieve the development of chronopharmaceutical dosage forms, currently, the siteand/or time-controlled release preparation with a designated initial lag time phase without drug release followed by a rapid release phase has been investigated. [5][6]14 These preparations enable us to predict and reproduce the drug absorption at the predetermined time and/or site. For this purpose, various designed dosage forms including the time clock system and sigmoidal release systems have been developed by using various unique techniques and functional polymers or additives.…”

Section: Resultsmentioning

confidence: 99%

“…[3][4] Time-controlled release preparations have been extensively developed to achieve time-and/or site-specific release. [5][6][7] In order to achieve the chronopharmaceutical design for these time-controlled release preparations, currently formulation design to control the lag time is prior to the substantial release of drug. [8][9] Recently, a TIMERx technology with an erosion mechanism was developed to achieve the chronotherapeutic delivery system.…”

Section: Introductionmentioning

confidence: 99%

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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: Resultsmentioning

confidence: 99%

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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“…Further, physiologically, a highly alkaline pH of 7.4 of the small intestine often contributes to premature drug release and failure of the pH-dependent release systems before reaching the colon [4]. The pH-independent release systems suffer from the drawback of incomplete drug release and have to be combined with other polymers that are either soluble at colonic pH or are capable of being degraded by colonic bacteria [5]. Many researchers have reported the use of natural or modified polysaccharides for sustained or colon delivery of drugs.…”

Section: Introductionmentioning

confidence: 99%

Investigations on chitosan-carboxymethyl guar gum complexes interpolymer complexes for colon delivery of fluticasone.

Kumar¹,

Tiwary²,

Kaur³

2010

Int j Drug delivery

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The present study was designed to formulate colon release tablets of fluticasone by employing cross linked chitosan (CH) and carboxymethyl guar gum (CMG) interpolymer complexes (IPC). Matrix tablets were prepared by wet granulation method using IPC as binder and coating agent. The IPC were characterized by Fourier transform infrared spectroscopy (FTIR). The uncoated and coated tablets were tested for their suitability as colon specific drug delivery system by in vitro dissolution studies. The coated tablets were evaluated for their pharmacodynamic performance after oral administration to TNBS induced ulcerative colitic rats. FTIR studies demonstrated that the IPC was formed through an electrostatic interaction between -COO − groups of CMG and -NH 3 + groups of CH. Tablets formulated with 50:50 CH:CMG as binder and coated with the respective ratio of IPC was capable of protecting the drug release in stomach and small intestine and delivering the drug in the colon. Histopathology of the rat colon after oral administration of these IPC film coated tablets revealed significantly greater (p<0.05) reduction in TNBS-induced ulcerative colitis The study confirmed that selective delivery of fluticasone to the colon can be achieved using cross-linked CH and CMG polysaccharides.

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“…In particular, systems for delayed release are meant to deliver the active principle after a programmed period following administration. These systems constitute a relatively new class of devices, the importance of which is especially connected with recent advances in chronopharmacology 6 .…”

Section: -3mentioning

confidence: 99%

Effect of Coating Solvent Ratio on the Drug Release Lag Time of Coated Theophylline Osmotic Tablets

Kanakal¹,

Sakeena²,

Azmin³

et al. 2009

Trop. J. Pharm Res

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In vitro and in vivo evaluation of an oral system for time and/or site-specific drug delivery

Cited by 133 publications

References 13 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

Investigations on chitosan-carboxymethyl guar gum complexes interpolymer complexes for colon delivery of fluticasone.

Effect of Coating Solvent Ratio on the Drug Release Lag Time of Coated Theophylline Osmotic Tablets

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