A comparative in vitro assessment of the drug release performance of pH-responsive polymers for ileo-colonic delivery

Ibekwe, Valentine C.; Fadda, Hala M.; Parsons, Gary E.; Basit, Abdul W.

doi:10.1016/j.ijpharm.2005.10.038

Cited by 127 publications

(74 citation statements)

References 27 publications

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“…Microbially triggered systems are based on compression coating of immediate release tablets with natural polysaccharides which are degraded by anaerobic microflora of the colon (5,9). However, various factors may quantitatively change the composition of the human gut ecosystem (10,11). Moreover, a larger amount of coat is required to prevent premature drug release due to higher hydrophilicity of the polysaccharides (12).…”

Section: Introductionmentioning

confidence: 99%

“…In vitro release of PDL from the resulting compression-coated tablets was evaluated in a dissolution medium devoid of any enzyme or simulated colonic fluid. The intention of this study was to develop a compression-coated tablet that can restrict the premature drug release to or below 10% for at least 6 h and thereafter provide almost a complete release within 4-6 h. Prednisolone has been chosen as a model drug because of its local pharmacological effect in colonic diseases (10).…”

Section: Introductionmentioning

confidence: 99%

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Compression-Coated Tablet for Colon Targeting: Impact of Coating and Core Materials on Drug Release

Maity

2015

AAPS PharmSciTech

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Abstract. This work was envisaged to develop compression-coated tablets using a blend of Ca +2 ion crosslinked carboxymethyl xanthan gum (CMXG) and sodium alginate (SAL) for delayed release of immediate pulse release tablets of prednisolone (PDL) in the colon without the need of colonic bacterial intervention for degradation of the polysaccharide coat. The core tablets containing PDL and other compatible excipients were prepared by direct compression method and subsequently compression coated with different ratios of CMXG and SAL. Long T lag , the time required to restrict the drug release below 10%, and short T rap , the time required for immediate release following the T lag , were considered as suitable release parameters for evaluation of colon targeting of PDL tablets. Among the various compression coats, a blend of CMXG and SAL in a ratio of 1.5:3.5 provided T lag of 5.12±0.09 h and T rap of 6.50±0.05 h. The increase in microcrystalline cellulose (MCC) and crospovidone (CP) in the core tablets did not change T lag significantly although decreased the T rap marginally. Inclusion of an osmogen in the core tablets decreased the T lag to 4.05±0.08 h and T rap to 3.56±0.06 h. The increase in coat weight to 225 mg provided a reasonably long T lag (6.06±0.09 h) and short T rap (4.36±0.20 h). Drug release from most of the formulations followed the Hixson-Crowell equation and sigmoidal pattern as confirmed by the Weibull equation. In conclusion, tablets, compression coated with CMXG and SAL in a ratio of 1.5:3.5 and having 225-mg coat weight, were apparently found suitable for colon targeting.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Compression-Coated Tablet for Colon Targeting: Impact of Coating and Core Materials on Drug Release

Maity

2015

AAPS PharmSciTech

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“…We have previously demonstrated that MAc-coated alginate beads may prevent cell release in acidic media and could protect cells under simulated gastric conditions at pH 2 for 90 min (THAM et al, 2014). However, under prolonged storage, subsequent diffusion of acidic media into the beads could occur leading to reduced cell viability (IBEKWE et al, 2006).…”

Section: Storagementioning

confidence: 99%

Survivability of encapsulated lactobacilli in high acid foods

Tham¹,

Peh²,

Liong³

2015

Acta Alimentaria

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This study aimed to evaluate the survivability of lactobacilli cells encapsulated in calcium alginate beads coated with methacrylic acid copolymers (MAc) in high acidic foods (orange juice and mayonnaise). Lactobacilli survived well at low temperature (4 °C) for 6 wk in orange juice, 4 wk in heat-treated orange juice, 12 wk in mayonnaise, and 8 wk in heat-treated mayonnaise (P<0.05), without affecting the acidity of orange juice and mayonnaise during storage. FTIR spectra showed that the characteristic peaks of calcium alginate and MAc were not altered, designating no high affi nity interaction between calcium alginate and MAc. DSC of MAc-coated alginate beads indicated an increased in melting temperature, demonstrating improvement in molecular orientation in the MAc-coated alginate beads compared to the control. Sensory evaluation revealed that panellists could detect the presence of MAc-coated alginate beads, leading to a lower acceptance score.

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“…Two and half grams of triethyl citrate as a plasticizer and 1.25 g talc as a glidant were added (14,15). Then the mixture was stirred for 24 h to ensure sufficient plasticization of the polymer and to get homogeneous solution (16).…”

Section: Coating Of the Prepared Tabletsmentioning

confidence: 99%

Once Daily, High-Dose Mesalazine Controlled-Release Tablet for Colonic Delivery: Optimization of Formulation Variables Using Box–Behnken Design

2011

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Abstract. The aim of this work was to statistically optimize a novel high-dose, mesalazine colonic delivery matrix system, potentially suitable for once daily administration, using simple wet granulation method. A hydrophobic-hydrophilic polymeric blend was used to manipulate drug release. A three-factor, three-level Box-Behnken design was used to construct polynomial models correlating the dependent and independent variables. Independent formulation variables were the percentages of the hydrophilic polymer Carbopol® 940, hydrophobic polymer Eudragit® RS, and the superdisintegrant croscarmellose sodium. The cumulative percentages of drug released at 6, 10, and 14 h were selected as dependent variables and restricted to 7.5-22.5% (Y 1 ), 42.5-57.5 % (Y 2 ), and 72.5-87.5% (Y 3 ), respectively. A second-order polynomial equation fitted to the data was used to optimize the independent formulation variables. Based on Box-Behnken experimental design, different mesalazine release profiles were obtained. The optimized formulation containing 5.72% Carbopol®, 9.77% Eudragit® RS, and 1.45% croscarmellose sodium was prepared according to the software determined levels. It provided a release profile which was very close to the targeted release profile, where the calculated values of f 1 and f 2 were 8.47 and 67.70, respectively, and followed zero-order release kinetics.

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A comparative in vitro assessment of the drug release performance of pH-responsive polymers for ileo-colonic delivery

Cited by 127 publications

References 27 publications

Compression-Coated Tablet for Colon Targeting: Impact of Coating and Core Materials on Drug Release

Compression-Coated Tablet for Colon Targeting: Impact of Coating and Core Materials on Drug Release

Survivability of encapsulated lactobacilli in high acid foods

Once Daily, High-Dose Mesalazine Controlled-Release Tablet for Colonic Delivery: Optimization of Formulation Variables Using Box–Behnken Design

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