Thermal treating as a tool for sustained release of indomethacin from Eudragit RS and RL matrices

Azarmi, Shirzad; Farid, J; Nokhodchi, Ali; Bahari-Saravi, S.M; Valizadeh, Hadi

doi:10.1016/s0378-5173(02)00378-2

Cited by 57 publications

(35 citation statements)

References 19 publications

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“…2,3) In reference to the annealing processes just described, the thermal treatment of polymeric pharmaceutical dosage forms has been studied in only a few cases. [7][8][9] Omelczuk and McGinity studied the effect of thermal treatment on the physical-mechanical and dissolution properties of tablets containing polylactic acid (PLA). 7) They showed that thermally treating the tablets to temperatures above the Tg of the PLA significantly retarded the drug release compared to tablets which were not thermally treated.…”

mentioning

confidence: 99%

Thermal Treating of Acrylic Matrices as a Tool for Controlling Drug Release

Hasanzadeh

Ghaffari

Monajjemzadeh

et al. 2009

CHEMICAL & PHARMACEUTICAL BULLETIN

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The purpose of the present study was to investigate the effect of thermal-treating on the release of ibuprofen from the granules prepared using aqueous dispersions of Eudragit. To accomplish this goal, different formulations were prepared using wet granulation method containing two different types of Eudragit aqueous dispersions, RS30D, RL30D and Avicel as filler. Tablets were prepared using direct compression method. The prepared tablets were thermally treated at 50 and 70°C for 24 h. The drug release from tablets was assessed before and after thermal-treating. The results of release study showed that, thermally-treating the tablets at the temperatures higher than glass transition temperature (Tg) of the polymer can decrease the drug release from matrices. For mechanistic evaluation of the effect of thermal-treating, powder X-ray diffraction (XPD), scanning electron microscopy (SEM), differential scanning calorimeter (DSC), Fourier transform infrared (FT-IR) and helium pycnometer have been employed. The SEM graphs showed that the tablets have smoother surface with less porosity after thermal-treating. FT-IR spectra showed no change in the spectrum of thermally-treated tablet compared to control. In DSC graphs, no crystalline change was seen in the heat-treated samples of ibuprofen tablets, but decreased and widened peak size were related to the probable formation of solid solution of ibuprofen in Eudragit matrix. The results of helium pycnometer showed a significant decrease in the total porosity of some heat-treated samples. This study revealed the importance of thermal treating on the drug release from sustained release tablets containing Eudragit polymer.

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confidence: 99%

Thermal Treating of Acrylic Matrices as a Tool for Controlling Drug Release

Hasanzadeh

Ghaffari

Monajjemzadeh

et al. 2009

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…As described in Azarmi et al, the effect of thermal treating causes a better coalescence of polymer particles with a decreased porosity and a smoother surface. 13 By altering the morphology of the outer layer, we successfully control the permeability and eliminate the initial burst, providing a more faithful picture of the experimental results. Table A1 in Appendix A.…”

Section: Discussionmentioning

confidence: 99%

“…Thermal treatments and compaction studies on Eudragit-RLPO matrix tablets revealed that the particles of the powder mixture move and diffuse during the heating process, coalescing the polymer particles and forming matrices with decreased porosity and increased tortuosity. [13][14] Porosity and tortuosity are important factors that affect the dissolution and release rate, as well as the possible formation of a thin polymer film on the surface of the tablet. 13 The release kinetics from laboratory studies show that, as the amount of polymer is increased, drug release from heated tablets approaches ''first-order kinetics'', i.e.…”

Section: Initializationmentioning

confidence: 99%

“…[13][14] Porosity and tortuosity are important factors that affect the dissolution and release rate, as well as the possible formation of a thin polymer film on the surface of the tablet. 13 The release kinetics from laboratory studies show that, as the amount of polymer is increased, drug release from heated tablets approaches ''first-order kinetics'', i.e. nearly linear release with respect to time (see Figure 7 in Baeumer et al).…”

Section: Initializationmentioning

confidence: 99%

“…nearly linear release with respect to time (see Figure 7 in Baeumer et al). 7 We simulate the creation of a film, or shell on the outside of the tablet as an effect of heating, as suggested in Azarmi et al 13 In the model, polymer particles can move towards the surface during thermal treatment, resulting in a higher chance of polymer being found on the tablet surface than in the interior. The user specifies the thickness of the shell layer (w in the program) and an imbalance factor b ≥ 1 that represents the preference of polymer particles to locate in the shell over the remainder of the tablet.…”

Section: Initializationmentioning

confidence: 99%

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Swallowing a cellular automaton pill: Predicting drug release from a matrix tablet

Buchla¹,

Hinow

Najera

et al. 2014

SIMULATION

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Matrix tablets are drug delivery devices designed to release a drug in a controlled manner over an extended period of time. We develop a cellular automaton (CA) model for the dissolution and release of a water-soluble drug and excipient from a matrix tablet of water-insoluble polymer. Cells of the CA are occupied by drug, excipient, water or polymer and the CA updating rules simulate the dissolution of drug and excipient and the subsequent diffusion of the dissolved substances. In addition we simulate the possible fracture of brittle drug and excipient powders during the tablet compression and the melting of the polymer during a possible thermal curing process. Different stirring mechanisms that facilitate the transport of dissolved drug in the fluid in which the tablet is immersed are modeled in the water cells adjacent to the boundary of the tablet. We find that our simulations can reproduce experimental drug release profiles. Our simulation tool can be used to streamline the formulation and production of sustained release tablets.

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