Optimization of pH conditions and characterization of polyelectrolyte complexes between gellan gum and cationic guar gum

Abstract

The present study was aimed to investigate optimum pH conditions for polyelectrolyte complexation between gellan gum (GG) and cationic guar gum (CGG). The pKa of both the polymers was determined using potentiometric titrations. The complex formation was investigated at three pH values (based upon the pKa interval of two polymers) and at different mixing ratios (ranging from 10:90 to 90:10). Zeta potential and turbidity studies elucidated the optimum pH and mixing ratio at which maximum interaction takes place between the polymers. The studies revealed neutral zeta potential, highest turbidity, and low transmittance at mixing ratio 30:70 and 40:60 (GG:CGG; pH 5.5), indicating maximum complex formation at these ratios. The percentage yield and viscosity studies of supernatant also revealed maximum interaction at these mixing ratios of polymers. The polyelectrolyte complexes (PECs) were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and for their swelling behavior in pH progression medium. The FTIR spectra confirmed formation of bonds between COO¯and -N + (CH 3 ) 3 of GG and CGG, respectively. DSC studies revealed the stability, affinity, and spontaneous nature of complexation between these polymers. The morphological changes detected through SEM studies in GG-CGG PECs exposed to different pH buffers also found to exhibit pH-dependent swelling. The FTIR spectra, DSC, SEM, and swelling studies of PECs treated with buffer pH 1.2 followed by buffer pH 7.4 suggested that PECs comprising 40:60 ratio of GG:CGG, prepared at pH 5.5, could be used to formulate a pH-sensitive drug delivery system.

Layer-by-layer assembly of cationic guar gum, cellulose nanocrystals and hydroxypropyl methylcellulose based multilayered composite films

“…These changes in the -OH band position depicts the formation of Hbonding that strengthens with the incorporation of HPMC layer in composite lm. Further, the CGg spectra showed sharp bands at 1653 cm − 1 and 1445 cm − 1 depicting the presence of quaternary ammonium cations (Dai et al 2020;Kaur et al 2018). In case of CGg/cCNCs and CGg/cCNCs/HPMC multilayered composite lm the characteristic band appeared at around 1635 cm − 1 which can be related to the electrostatic interactions between carboxylate groups of cCNCS and quaternary ammonium cations of CGg and the overlapping of characteristic bands of CGg and cCNCs (Dai et al 2020;Kaur et al 2018).…”

“…Further, the CGg spectra showed sharp bands at 1653 cm − 1 and 1445 cm − 1 depicting the presence of quaternary ammonium cations (Dai et al 2020;Kaur et al 2018). In case of CGg/cCNCs and CGg/cCNCs/HPMC multilayered composite lm the characteristic band appeared at around 1635 cm − 1 which can be related to the electrostatic interactions between carboxylate groups of cCNCS and quaternary ammonium cations of CGg and the overlapping of characteristic bands of CGg and cCNCs (Dai et al 2020;Kaur et al 2018). Further the band at 1445 cm − 1 shifted to lower wavenumber at 1425 cm − 1 for CGg/cCNCs lm, suggesting the strong electrostatic interaction or H-bonding between CGg and cCNCs (Dai et al 2017;Kaur et al 2018).…”

“…In case of CGg/cCNCs and CGg/cCNCs/HPMC multilayered composite lm the characteristic band appeared at around 1635 cm − 1 which can be related to the electrostatic interactions between carboxylate groups of cCNCS and quaternary ammonium cations of CGg and the overlapping of characteristic bands of CGg and cCNCs (Dai et al 2020;Kaur et al 2018). Further the band at 1445 cm − 1 shifted to lower wavenumber at 1425 cm − 1 for CGg/cCNCs lm, suggesting the strong electrostatic interaction or H-bonding between CGg and cCNCs (Dai et al 2017;Kaur et al 2018). For CGg/cCNCs/HPMC multilayered composite lm, the splitting of the 1445 cm − 1 band was apparent at 1440 cm − 1 and 1415 cm − 1 .…”

An Extensive Review of Natural Polymers Used as Coatings for Postharvest Shelf-Life Extension: Trends and Challenges

“…Therefore, it was suggested that flexibility and hardness can be better controlled through blends with natural and synthetic polymers [ 103 ]. The negative charge of gellan allows the production of polyelectrolytes with other oppositely charged polymers such as chitosan and cationic guar gum [ 104 , 105 ]. The gelling properties of gellan gum depend on several factors such as the presence of cations, pH, temperature, and polymer concentration [ 103 , 106 ].…”

A Review of Gum Hydrocolloid Polyelectrolyte Complexes (PEC) for Biomedical Applications: Their Properties and Drug Delivery Studies

“…Mass ratio G:C = 5:10, 6:12, 7:14 [58] Tragacanth gum (T) Insulin (I) (% w/w) ratio T:I = (0.1, 0.5, 1): 0.02, pH of Tragacanth was adjusted to 3.7, 4.3, 4.6 or 6 [59] Xanthan gum Chitosan % weight ratio X:C = 1.5:1.5 [60] Gellan gum Cationic guar gum Mixing ratios G:CGG = 10:90 until 90:10, pH 3.72, 5.5, and 7.13 [61] Okra gum (O) Chitosan Ratio O:C = 10:90 until 90:10, pH 5.0 [62] Xanthan gum Chitosan (% w/v) ratio X:C = 0.5:0.5 [63] Gellan gum Chitosan Ratio G:C = 10:90 until 65:35, 60 Arabinogalactans gum acacia (GA)…”