Effect of drug loading extent on the in vitro release kinetic behaviour of nifedipine from polyacrylate microspheres

Benita, Simon; Barkai, Amiram I.; Pathak, Y. V.

doi:10.1016/0168-3659(90)90102-y

Cited by 39 publications

(23 citation statements)

References 10 publications

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“…Giving that AZT is highly hydrophilic (10 mg/mL), its 34.0±9.0% loading into the interior of the microballoons was considered satisfactory. Floating microparticulate gastroretentive systems similar to that obtained in this study have shown higher loading rate for poorly water-soluble drugs (9,10,(12)(13)(14)19). The low yield here was probably related to the drug's diffusion into the aqueous medium during microballoon formation.…”

Section: Floating and Loadingmentioning

confidence: 54%

“…Similar structures were called microballoons (9,(12)(13)(14)31). The microballoon formation mechanism proposed in this study is similar to the method proposed by Benita et al (19). Prior to obtaining this system, several pre-formulation studies (data not presented) were carried out, under different conditions and using different kinds of polymers.…”

Section: Resultsmentioning

confidence: 84%

“…1). Similar structures to this have been denominated microballoons (9,(12)(13)(14)19,31). To attain this structure, the flow rate of the AZT/Eudragit S100 solution was adjusted to 2 mL.min −1 , the stirring speed of the PVA K30 solution set to 250 rpm, and the temperature of the system kept between 24°C and 28°C.…”

Section: Resultsmentioning

confidence: 99%

“…The FGS was prepared using the diffusion and evaporation of the solvent (9,10,19). AZT and Eudragit S100 (1:5) were dissolved separately in an adequate amount of ethanol and mixed to obtain an isopropanol/ dichloromethane (2:5) solution.…”

Section: Floating Gastroretentive System Preparationmentioning

confidence: 99%

“…Many studies have been published on the usage of microballoons to achieve FGS for modified release of drugs with different properties (16)(17)(18). Although orally administered water-soluble drugs may also present bioavailability problems, the systems of modified release have been proposed mostly for drugs of poor solubility in water (9,10,19).…”

Section: Introductionmentioning

confidence: 99%

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Development and Evaluation of a Floating Multiparticulate Gastroretentive System for Modified Release of AZT

et al. 2011

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Abstract. The aim of this study was to develop and evaluate a floating multiparticulate gastroretentive system for the modified release of zidovudine (AZT). AZT was used as a model drug water-soluble at therapeutic doses. The floating gastroretentive system was obtained by co-precipitation, after solvent diffusion and evaporation. The proposed system was evaluated in vitro for particle morphology, lag time and floating time, loading rate, release profile, and the release kinetic of AZT release. AZT's physicochemical characteristics were evaluated by differential scanning calorimetry (DSC), X-ray diffraction (XDR) and infrared spectroscopy (IR). The particles obtained were sphere-shaped, hollow, and had porous walls. The floating was immediate, and floating time was higher than 12 h. The loading rate was 34.0±9.0%. The system obtained had an extended release. DSC and XDR results showed a modification in AZT's solid state. IR spectroscopy revealed that the chemical structure of the AZT was unchanged. The hollow microballoons presented gastroretentive, floating, and extended-release properties.

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Section: Floating and Loadingmentioning

confidence: 54%

Section: Resultsmentioning

confidence: 84%

Section: Resultsmentioning

confidence: 99%

Section: Floating Gastroretentive System Preparationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Development and Evaluation of a Floating Multiparticulate Gastroretentive System for Modified Release of AZT

et al. 2011

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Drug–polymer interaction and its significance on the physical stability of nifedipine amorphous dispersion in microparticles of an ammonio methacrylate copolymer and ethylcellulose binary blend

Huang

Wigent

Schwartz

2008

Journal of Pharmaceutical Sciences

114

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Zidovudine-Poly(l-Lactic Acid) Solid Dispersions with Improved Intestinal Permeability Prepared by Supercritical Antisolvent Process

Yoshida

Balcão

Vila

et al. 2015

Journal of Pharmaceutical Sciences

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A supercritical antisolvent (SAS) process for obtaining zidovudine-poly(L-lactic acid) (PLLA) solid dispersions (SDs) was used to attain a better intestinal permeation of this drug. A 3(2) factorial design was used, having as independent variables the ratio 3'-azido-2'3'-dideoxythymidine (AZT)-PLLA and temperature/pressure conditions, as dependent variables the process yield and particle macroscopic morphology. AZT-PLLA production batches were carried out by the SAS process, and the resulting products evaluated via scanning electron microscope, X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared analyses. From the nine possible combinations of tests performed experimentally, only one combination did not produced a solid. The L3 batch of SD, produced with 1:2 (AZT-PLLA) ratio, resulted in a 91.54% yield, with 40% AZT content. Intestinal permeability studies using the AZT-PLLA from L3 batch led to an AZT permeability of approximately 9.87%, which was higher than that of pure AZT (∼3.84%). AZT remained in crystalline form, whereas PLLA remained in semicrystalline form. AZT release is controlled by a diffusion mechanism. It has been demonstrated that it is possible to use PLLA carrier and SAS process to obtain SD, in a single step.

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Effect of drug loading extent on the in vitro release kinetic behaviour of nifedipine from polyacrylate microspheres

Cited by 39 publications

References 10 publications

Development and Evaluation of a Floating Multiparticulate Gastroretentive System for Modified Release of AZT

Development and Evaluation of a Floating Multiparticulate Gastroretentive System for Modified Release of AZT

Drug–polymer interaction and its significance on the physical stability of nifedipine amorphous dispersion in microparticles of an ammonio methacrylate copolymer and ethylcellulose binary blend

Zidovudine-Poly(l-Lactic Acid) Solid Dispersions with Improved Intestinal Permeability Prepared by Supercritical Antisolvent Process

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