Hollow microspheres and aqueous phase behavior of pH-responsive poly(methyl methacrylate-co-methacrylic acid) copolymers with a blocky comonomer distribution

Manokruang, Kiattikhun; Manias, Evangelos

doi:10.1016/j.matlet.2009.01.046

Cited by 16 publications

(10 citation statements)

References 21 publications

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“…The structural changes on glassy polymer surfaces have been attributed to possible effects of STRESS and strains on surface as the material swells [9]. This is suggested to be as a result of response to any of the following: effects of temperature change, effects of activity differences, and effects of prehistory and sample dimensions [10]- [12]. The release has therefore been modeled as non-fickian where diffusion and dissolution depends on stress on the matrix and not on concentration gradient.…”

Section: Analysis Of Releasementioning

confidence: 99%

Controlled-Release Analysis of Potassium Permanganate Using PMMA Matrix

Ighere¹,

Chawla²

2014

JMMCE

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Excess amount of potassium permanganate has often been used in-situ for chemical oxidation of contaminated sites. The consequences are not limited to secondary contamination and cost but also inefficient remediation. Encapsulation of permanganate using PMMA enables controlled dissolution of the oxidant and aids long-term processes. This paper focuses on the oxidant release efficiency from polymer matrix and analysis of data using existing models for glassy polymers. The efficiency profile obtained using mass ratios of 2:1, 4:1, and 8:1 of PMMA to KMnO 4 showed a decrease in the extent of release with increasing mass ratio with 79%, 55.35% and 33.59% respectively. Patches were noticed on the surfaces of PMMA after the release of KMnO 4 , these were attributed to crevices created by the non-fickian diffusion of the oxidant.

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Section: Analysis Of Releasementioning

confidence: 99%

Controlled-Release Analysis of Potassium Permanganate Using PMMA Matrix

Ighere¹,

Chawla²

2014

JMMCE

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“…19,20 The final one contains ionisable groups (carboxylic acid) and has been the focus of intensive research, since its pH-dictated ionization can be utilized for the development of systems with reversible water solubility controlled by pH. 21,22 This polymer is typically water-soluble when charged, but becomes water-insoluble when neutral. These materials also find application in areas such as controlled release of drugs in the form of hollow microspheres for the protection of sensitive species in acidic media.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of the dissolution profile of the diuretic hydrochlorothiazide by elaboration of microspheres

Larbi

Merine

Ramli³

et al. 2018

JSCS

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Hydrochlorothiazide (HCTZ), which was developed and introduced in the late 1950s, is still one of the most frequently employed drugs in antihypertensive treatments. Its poor aqueous solubility is one of the reasons for its limited bioavailability after oral administration. The present paper provides details of the preparation of HCTZ-loaded microspheres by the solvent evaporation technique. A total of seven formulations were prepared using ethyl cellulose, poly(?-caprolactone) (PCL), ?-cyclodextrin (?-CD) and synthesized poly-(methyl methacrylate) (PMMA) of different molecular weights in different drug-to-carrier ratios in order to investigate their effect on the encapsulation efficiency and drug release kinetics. The prepared formulations were characterized by Fourier transform-infrared (FTIR) spectroscopy, powder X-ray diffractometry, differential scanning calorimetry, yield, drug loading, optical microscopy, surface morphology by scanning electron microscopy (SEM), and in vitro release studies in simulated gastrointestinal tract fluid. The loading efficiency was found in the range from 18?0.34 to 39?0.95 %. The microspheres were spherical, and the mean Sauter diameter (d32) of the obtained microparticles ranged from 26?0.16 to 107?0.58 ?m. The presence of the drug and polymer carriers in the microparticles was confirmed by FTIR spectroscopy and XRD analysis. In vitro dissolution studies showed that the release rate was largely affected by the characteristics of the microparticles, namely the particle size and the nature of the matrix. The release data are best fitted to the Higuchi model with high correlation coefficients (r?).

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“…Colloidosomes are hollow particles whose shells are composed of a closed-packed layer of colloidal particles [1]. The work on colloidosomes was first reported by Velev and colleagues in 1996 [2] although the term was introduced later by Dinsmore et al [1].This hollow particle plays significant roles in microencapsulation: a process in microscopic formation of thin coatings of wall material around an active ingredient [3] This process has been used in varies applications such as controlled release of drugs [4], aroma [5], food industries [6] and protection of biologically active species [7]. Microcapsules preparation methods can takes several steps which might be complex, time consuming and in need of binders [1,8].…”

Section: Introductionmentioning

confidence: 99%

The Formulation Parameter Influence on PHB Hollow Colloidosomes Formation Prepared via Two Step Solvent Evaporation Method

SyakirISMAIL¹,

Abdullah²,

Shahidan³

2018

IJCRSET

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This study demonstrates polyhydroxybutyrate (PHB) as a potential polymer to produce colloidosomes trough two step solvent evaporation method. In this study, the surfactant concentrations, molecular weight and oil phase volume were varied which proven that a range of average diameter, Dave and higher yield of PHB colloidosomes can be successfully achieved. The Dave increased slightly by 0.03 µm when surfactant concentration decreases from 1.2 wt.% to 0.5 wt.%. However, Dave increases significantly from 1.33 to 8.68µm when the average molecular weight, Mw of surfactant used increases from 13,000 to 130,000. In addition, the colloidosomes yield also increases as the surfactant average Mw increases. This study also displayed the simplicity of the method, where it is straightforward and used commercially available materials.

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Hollow microspheres and aqueous phase behavior of pH-responsive poly(methyl methacrylate-co-methacrylic acid) copolymers with a blocky comonomer distribution

Cited by 16 publications

References 21 publications

Controlled-Release Analysis of Potassium Permanganate Using PMMA Matrix

Controlled-Release Analysis of Potassium Permanganate Using PMMA Matrix

Enhancement of the dissolution profile of the diuretic hydrochlorothiazide by elaboration of microspheres

The Formulation Parameter Influence on PHB Hollow Colloidosomes Formation Prepared via Two Step Solvent Evaporation Method

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