Optima: A Windows-Based Program for Computer-Aided Optimization of Controlled-Release Dosage Forms

Dr, Lu; Abu-Izza, Khawla; W, Chen

doi:10.3109/10837459609031435

Cited by 10 publications

(2 citation statements)

References 4 publications

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“…A direct fitting of the drug-release data to the non-linear equations described above is usually avoided by performing a linear transformation of the data, followed by regression analysis. Nevertheless, this method may not be mathematically accurate, as it uses transformed values (logarithms) instead of the original data [24]. Therefore, a direct non-linear fitting of the experimental results was carried out in the present work, for each of the mathematical models considered (through minimisation of the sum of the squared residuals).…”

Section: Kinetic Mechanismmentioning

confidence: 99%

Influence of cellulose ether polymers on ketoprofen release from hydrophilic matrix tablets

Vueba

Carvalho

Veiga

et al. 2004

European Journal of Pharmaceutics and Biopharmaceutics

141

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The present work reports the study of different ketoprofen:excipient formulations, in order to determine the effect of the polymer substitution and type of diluent on the drug-release mechanism. Substituted cellulose-methylcellulose, hydroxypropylcellulose and hydroxypropylmethylcellulose were used as polymers, while lactose monohydrate and beta-cyclodextrin were tested as diluents. Distinct test formulations were prepared, containing 57.14% of ketoprofen, 20.00% of polymer, 20.29% of diluent, and 1.71% of talc/0.86% of magnesium stearate as lubricants. The tablets were tested for their drug content, weight variation, hardness, thickness, tensile strength, friability, swelling and release ratio. Polymers MC25 and HPC were found not to be appropriate for the preparation of modified release ketoprofen hydrophilic matrix tablets, while HPMC K15M and K100M showed to be advantageous. The analysis of the release profiles in the light of distinct kinetic models (zero-order, first-order, Higuchi and Korsmeyer-Peppas) led to the conclusion that the type of polymer did not influence the release mechanism of the drug. The mean dissolution time (MDT) was determined, the highest MDT value being obtained for HPMC formulations. Moreover, the drug-release process was found to be slightly influenced by the type of diluent, either lactose or beta-cyclodextrin.

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Section: Kinetic Mechanismmentioning

confidence: 99%

Influence of cellulose ether polymers on ketoprofen release from hydrophilic matrix tablets

Vueba

Carvalho

Veiga

et al. 2004

European Journal of Pharmaceutics and Biopharmaceutics

141

View full text Add to dashboard Cite

show abstract

“…The direct fitting of the drug release data to the nonlinear equations mentioned earlier is usually avoided through linear transformation of the data, followed by a linear regression analysis. However, this method may not be mathematically accurate, since it uses transformed values (logarithms) instead of the original data (Lu et al, 1996). Consequently, a direct nonlinear fitting of the experimental results was performed in this work, for each of the mathematical models considered (through minimisation of the sum of the squared residuals).…”

Section: Kinetic Mechanismmentioning

confidence: 99%

Relaxation versus diffusion on the diclofenac sodium release from matrix tablets containing hydroxypropylmethylcellulose and/or chitosan

Vueba¹,

Carvalho²,

Pina³

2013

Afr. J. Pharm. Pharmacol.

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Different formulations of diclofenac sodium (DS) containing hydroxypropylmethylcellulose (HPMC) and/or chitosan were prepared, with a view to appraise the effect of the said polymers on the drug release behaviour from matrix tablets prepared by the direct compression method. The tablets were tested for different assays, including swelling and release performance. Differential scanning calorimetry (DSC) and Raman spectroscopy were performed in order to estimate the compatibility between the matrix components (DS and excipients). From the DSC and Raman results, non-negligible drug:excipient interactions were detected, although, these were found not to constitute an incompatibility effect. The dissolution tests and the kinetic analysis data indicated that the rate and the mechanism of DS release from tablets are mainly controlled by the drug/polymer ratio. The release rate became slower for a high polymer content of HPMC. Moreover, the results demonstrated that chitosan could accelerate the drug release with lower amount in the formulation. The analysis of the drug release profile was performed in the light of distinct kinetic mathematical models. Release from formulations F2 and F3 occurs by an anomalous transport mechanism (coupling of diffusion/erosion mechanisms), with Kosmeyer-Peppas exponent (n) values of 0.626 and 0.706, respectively. The balance between diffusion and polymer erosion competing mechanisms of drug release were assessed by the Peppas-Sahlin model.

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The effect of isopropanol addition on enhancement of transdermal controlled release of ibuprofen from ethylene vinyl acetate copolymer membranes

Emami

Hassannejad

Hasani-Sadrabadi

et al. 2011

J of Applied Polymer Sci

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This work reports the study of the addition of isopropanol on controlled release of ibuprofen from ethylene vinyl acetate (EVAc) copolymer membranes. An EVAc solution in cyclohexane (4% w/v) containing triethyl citrate (7% w/v) as plasticizer was mixed with ibuprofen at three different concentrations of 4, 6, and 8%. Isopropanol was mixed with each of the previous mixtures to form solutions of 1, 3, and 5% isopropanol concentrations. Samples were solvent cast on glass petridishes to form membranes. Home-made diffusion cells were used for in vitro study. These cells were composed of two compartments, donor (exposed to ambient conditions), and receptor (including buffer solution maintained at 37 C). Each cell was equipped with a sampling port and water in and out system. An ultraviolet spectrometer at 222 nm was used to measure release rates of obtained membranes. The diffusion mechanism for drug release was examined by zero-order, first-order, Higuchi and Korsmeyer-Peppas theories to confirm the obtained membranes follow the matrix-type system. By increasing the drug concentration from 4 to 8%, drug release (cumulative amount) was improved from 20 (47.5%) to 30 (36%) lg/ cm 2 after 24 h. Addition of 5% isopropanol to the above samples (4 and 8% loading) further increased drug release to 24 and 43 lg/cm 2 . Results were in good agreement with the Korsmeyer-Peppas theory for samples with 4 (% w/w) of ibuprofen. The highest percentage of drug release after 24 h was 59% for the sample with 4% drug loading compared to 50% for the sample with 8% drug loading, both with 5% isopropanol.

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Optima: A Windows-Based Program for Computer-Aided Optimization of Controlled-Release Dosage Forms

Cited by 10 publications

References 4 publications

Influence of cellulose ether polymers on ketoprofen release from hydrophilic matrix tablets

Influence of cellulose ether polymers on ketoprofen release from hydrophilic matrix tablets

Relaxation versus diffusion on the diclofenac sodium release from matrix tablets containing hydroxypropylmethylcellulose and/or chitosan

The effect of isopropanol addition on enhancement of transdermal controlled release of ibuprofen from ethylene vinyl acetate copolymer membranes

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