Study of the critical points of experimental HPMC–NaCMC hydrophilic matrices

Melgoza, Luz María; Villalobos, Rafael; Caraballo, Isidoro

doi:10.1016/j.ijpharm.2009.10.048

Cited by 17 publications

(5 citation statements)

References 19 publications

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“…Furthermore, these findings are in agreement with the conclusions of the previous study dealing with matrices containing HPMC, NaCMC, and KCl as model drugs [16]. This previous paper reports a partial collaboration between the two polymers in order to establish the gel layer.…”

Section: Resultssupporting

confidence: 91%

“…Ternary hydrophilic matrix systems were prepared in order to study the drug release behavior of these systems, investigating the existence of a critical excipient barrier and the possible differences with this found in a previous work using KCl as model drug [16]. …”

Section: Resultsmentioning

confidence: 99%

“…It has been demonstrated that the excipient percolation threshold influences the drug release from hydrophilic matrix systems [16, 21]. …”

Section: Resultsmentioning

confidence: 99%

“…In this work, the existence of an excipient critical barrier (in matrices prepared with each single polymer as well as matrices containing mixtures of the two polymers) was observed, and it was demonstrated that the excipients showed a partial collaboration between them in order to establish the gel layer [16]. …”

Section: Introductionmentioning

confidence: 99%

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Collaboration between HPMC and NaCMC in order to Reach the Polymer Critical Point in Theophylline Hydrophilic Matrices

Melgoza

Aguilar-de-Leyva

Caraballo

2012

The Scientific World Journal

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Percolation theory has been applied in order to study the existence of critical points as well as the possibility to find a “combined percolation threshold” for ternary hydrophilic matrices prepared with HPMC, NaCMC, and theophylline. For this purpose, different batches of ternary as well as binary hydrophilic matrices have been prepared. Critical points have been found for binary hydrophilic matrices between 21.5 and 31.3% (v/v) of HPMC and between 39 and 54% (v/v) of NaCMC, respectively. In a previous work carried out with the same polymers but a much more soluble drug (KCl), it was demonstrated the existence of a partial collaboration between the polymers in order to establish the gel layer. In this work, it has been observed for the first time the need of a minimum concentration of one of the matrix-forming polymer (between 10 and 20% v/v, approximately) for establishing an effective collaboration.

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Section: Resultssupporting

confidence: 91%

Section: Resultsmentioning

confidence: 99%

“…It has been demonstrated that the excipient percolation threshold influences the drug release from hydrophilic matrix systems [16, 21]. …”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Collaboration between HPMC and NaCMC in order to Reach the Polymer Critical Point in Theophylline Hydrophilic Matrices

Melgoza

Aguilar-de-Leyva

Caraballo

2012

The Scientific World Journal

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“…NaCl modifies the release rate of drug by preferential solubulity thereby creating pores and channels into the matrix through which drug can be released from the core. Utilization of NaCl in modulating drug release has previously been reported (Contreras et al, 2010). Formulation IX-NaCl was designed to evaluate the effect of NaCl on drug release from central core matrix tablet.…”

Section: Resultsmentioning

confidence: 99%

Release Modification of Indomethacin Controlled Release Press Coated Tablets

2016

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The study was carried out to evaluate the release modification of indomethacin press coated tablets through different polymers. Several batches of press coated tablets were prepared with indomethacin and Avicel PH 102. The core tablet was compression coated with minimal compression pressure. Formulation IX was modified by incorporating PEG 6000, sodium chloride and sodium lauryl sulphate (SLS). In vitro dissolution studies of the formulations of different excipients were done at pH 7.2 in phosphate buffer using USP apparatus 2 (paddle method) at 50 rpm and 37 ± 0.5 °C temperature. The drug release data was treated in different mathematical fashion to identify the kinetic behaviour. It was found that, drug release which was inversely proportional to the amount of xanthan gum in the coating formulations was significantly changed by the polymers used in the study. Incorporation of SLS caused the drug to be released in near zero order fashion. Drug release was found to follow Higuchi mechanism for all the formulations. The study reveals that the polymers used may be a significant factor for the discrepancy in release rate of indomethacin.

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