Background: In recent time, microwave-assisted procedures are becoming popular ecofriendly
approaches in the Green Chemistry. In chemical processing, microwave irradiation is evolving
as an efficient tool and has been utilized in various fields including polymer chemistry. Microwave
irradiation extends its use in the carboxymethylation of polysaccharides like starch, hemicellusose and
chitosan. However, to date, no study has reported the microwave-assisted carboxymethylation of xanthan
gum. In this background, the aim of the present investigation was to synthesize microwaveassisted
carboxymethyl xanthan gum.
Methods: In the present study, eco-friendly synthesis of carboxymethyl xanthan gum was carried out using microwave.
The optimum reaction conditions for the carboxymethylation of xanthan gum were studied by independent variation of six
parameters. The synthesized gum was characterized by Fourier transform infrared, X-ray diffraction, differential scanning
calorimetric analysis and scanning electron microscopy. Further, to evaluate drug release behavior, matrix tablets of diltiazem
hydrochloride were prepared.
Results: The results revealed maximum degree of substitution (0.818) with exposure time of 4 min, microwave power of
360 W, 3 g of NaOH, 1.5 g of monochloroacetic acid and alkalization time of 30 min. In characterization studies, non
toxic and semi-crystalline nature of carboxymethyl xanthan gum was observed. The drug release data showed a significantly
faster release of diltiazem hydrochloride from matrix tablets of carboxymethyl xanthan gum as compared to tablets
prepared using xanthan gum.
Conclusion: We suggest that the microwave-assisted carboxymethylation is an efficient Green Chemistry method for the
synthesis of carboxymethyl xanthan gum with zero toxicity rating and Super Case II transport.