pH-sensitive sodium alginate/poly(vinyl alcohol) hydrogel beads prepared by combined Ca2+ crosslinking and freeze-thawing cycles for controlled release of diclofenac sodium

Hua, Shuibo; Ma, Haizhen; Li, Xun; Yang, Huixia; Wang, Aiqin

doi:10.1016/j.ijbiomac.2010.03.004

Cited by 389 publications

(164 citation statements)

References 27 publications

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“…Because of easy availability, cost effectiveness, biodegradability, and biocompatibility [1], natural polymers have been used extensively over the past few decades [2][3][4]. Among them, alginate, a type of polysaccharides composed of 1,4 --d-mannuronic acid (M-block) and -l-guluronic acid (Gblock), is plentiful in our environment [5,6].…”

Section: Introductionmentioning

confidence: 99%

The Size Stability of Alginate Beads by Different Ionic Crosslinkers

Huang

Lin

2017

Advances in Materials Science and Engineering

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Few studies have discussed the stability of gelled alginate bead size. Therefore, the present study investigated the dynamic shrinkage of gelled alginate beads affected by two common ionic crosslinkers at different concentrations and temperatures. The results indicate that the gelled alginate beads gradually shrank with longer gelling times. The beads incubated in a Ca 2+ solution shrank more dramatically than those incubated in a Ba 2+ solution. Those incubated at room temperature exhibited greater shrinkage than those incubated at a low temperature. A 25% size reduction occurred in the 1% Ca 2+ solution at room temperature after 300 minutes of gelling time. The alginate beads gelled took at least 120 minutes to become stable after the ionic gelation process.

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Section: Introductionmentioning

confidence: 99%

The Size Stability of Alginate Beads by Different Ionic Crosslinkers

Huang

Lin

2017

Advances in Materials Science and Engineering

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“…Due to its polyelectrolyte nature as well as good film forming ability, NaAlg has been widely explored in biomedical area as a drug carrier (18,19). The presence of carboxylic acid groups in NaAlg makes it a pH-sensing device (20), but the fast dissolution of the drug from the NaAlg hydrogel at higher pH is a major limitation. To overcome this, NaAlg has been blended with GG to make it a pH-sensitive device in the CR of proteins (21).…”

Section: Introductionmentioning

confidence: 99%

Novel pH- and Temperature-Responsive Blend Hydrogel Microspheres of Sodium Alginate and PNIPAAm-g-GG for Controlled Release of Isoniazid

2012

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Abstract. This paper reports the preparation and characterization of novel pH-and thermo-responsive blend hydrogel microspheres of sodium alginate (NaAlg) and poly(N-isopropylacrylamide)(PNIPAAm)-grafted-guar gum (GG) i.e., PNIPAAm-g-GG by emulsion cross-linking method using glutaraldehyde (GA) as a cross-linker. Isoniazid (INZ) was chosen as the model antituberculosis drug to achieve encapsulation up to 62%. INZ has a plasma half-life of 1.5 h, whose release was extended up to 12 h. Fourier transform infrared spectroscopy was used to confirm the grafting reaction and chemical stability of INZ during the encapsulation. Differential scanning calorimetry was used to investigate the drug's physical state, while powder X-ray diffraction confirmed the molecular level dispersion of INZ in the matrix. Scanning electron microscopy confirmed varying surface morphologies of the drug-loaded microspheres. Temperature-and pH-responsive nature of the blend hydrogel microspheres were investigated by equilibrium swelling, and in vitro release experiments were performed in pH1.2 and pH7.4 buffer media at 37°C as well as at 25°C. Kinetics of INZ release was analyzed by Ritger-Peppas empirical equation to compute the diffusional exponent parameter (n), whose value ranged between 0.27 and 0.58, indicating the release of INZ follows a diffusion swelling controlled release mechanism.

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“…[2,10] Tamarind seed gum (TG) is a natural polymer well known for its applicability in food industry. It consists of non-ionic, neutral, branched polysaccharide chain having cellulose-like backbone.…”

Section: Introductionmentioning

confidence: 99%

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Mali

2016

AJP

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Aim: The present investigation deals with the formulation of floating-bioadhesive matrix tablets of verapamil hydrochloride (VH). The main objective of this work was to overcome the limitations of the conventional floating matrix tablets. Materials and Methods: Hydroxypropyl methylcellulose (HPMC) K15M was used as a matrixforming agent whereas carboxymethyl tamarind gum (CMTG) was used to promote bioadhesion. Systematic optimization was performed using a central composite design with two independent variables and six dependent variables. Tablets were prepared by using the wet granulation method. The effect of polymer ratio (HPMC:CMTG) and sodium bicarbonate (SB) concentration on the total floating time (TFT), floating lag time (FLT), bioadhesion, swelling, and drug release (DR) was studied and optimized. Results and Discussion: Floating-bioadhesive matrix tablets of VH showed good physicochemical properties. The FLT was within the range of 2.87-14.41 min and TFT was more than 12 h. The tablets showed 17-30% of burst release in the 1 st h and controlled release over a period of 12-h. DR and swelling were significantly (P < 0.05) affected by polymer ratio and concentration of SB in formulation. The polynomial mathematical models, generated for various response variables using multiple regression analysis, were found to be statistically significant (P < 0.05). Optimized batch showed FLT of 6.14 min, bioadhesion of 17.23 g, swelling of 74.83% at 5 h, and DR of 75.48% at 10 h, with anomalous release mechanism. The observed values were near to the predicted values obtained by the experimental design. Conclusion: The floating-bioadhesive tablets of VH prepared using HPMC and CMTG exhibited a potential to retain and control the release of drug in stomach for more than 12 h and may be used as an alternative to the conventional floating tablets of VH.

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pH-sensitive sodium alginate/poly(vinyl alcohol) hydrogel beads prepared by combined Ca2+ crosslinking and freeze-thawing cycles for controlled release of diclofenac sodium

Cited by 389 publications

References 27 publications

The Size Stability of Alginate Beads by Different Ionic Crosslinkers

The Size Stability of Alginate Beads by Different Ionic Crosslinkers

Novel pH- and Temperature-Responsive Blend Hydrogel Microspheres of Sodium Alginate and PNIPAAm-g-GG for Controlled Release of Isoniazid

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