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Background: The use of synthetic and semi-synthetic materials in drug delivery systems has associated drawbacks like costly synthesis, toxicity, and biocompatibility issues. Therefore, there is a need to introduce novel materials to overcome such issues. Naturally occurring and water-swellable polysaccharides are advantageous in overcoming the above-mentioned issues. Therefore, we are reporting a novel hydrogel (SSH) isolated from the seeds of Salvia spinosa as a sustained release material. Methods: SSH was explored for its pH-dependent and salt-responsive swelling before and after compression in a tablet form. Stimuli-responsive swelling and deswelling were also monitored at pH 7.4 and pH 1.2 in deionized water (DW) and normal saline and DW and ethanol. The sustained-release potential of SSH-based tablets was monitored at gastrointestinal tract (GIT) pH. The transit of SSH tablets was ascertained through an X-ray study. Results: The swelling of SSH in powder and tablet form was found in the order of DW > pH 7.4 > pH 6.8 > pH 1.2. An inverse relation was found between the swelling of SSH and the concentration of the salt solution. The SSH showed stimuli-responsive swelling and de-swelling before and after compression, indicating the unaltered nature of SSH even in a closely packed form, i.e., tablets. Sustained release of theophylline (< 80%) was witnessed at pH 6.8 and 7.4 during the 12 h study following zeroorder kinetics, and radiographic images also showed 9 h retention in GIT. Conclusion: These investigations showed the potential of SSH as a pH-sensitive material for sustained and targeted drug delivery.

Herein, the focus of this research is to develop a novel pH-responsive and non-toxic hydrogel via free radical polymerization of Artemisia vulgarisseed mucilage/hydrogel (AVH) and acrylic acid (AA) monomer using methylene-bis-acrylamide (MBA) as a cross-linking agent. The prepared copolymer hydrogel (AVH-co-AA) was characterized by FTIR and solid-state CP/MAS 13C NMR spectroscopic techniques. The thermal analysis revealed AVH-co-AA as a thermally stable material. The effect of pH and concentration of AVH, AA, and MBA on the dynamic and equilibrium swelling, sol-gel analysis, porosity measurement, drug loading, and in vitrodrug release pattern of AVH-co-AA were evaluated. The maximum swelling of AVH-co-AA and the highest release of the drug (pantoprazole) was noticed at pH 7.4. The swelling indices (15.99 ± 1.1 to 26.07 ± 1.1 g/g at pH 7.4), porosity (33.41–56.03%), drug loading (103.4 ± 1.5 to 127.9 ± 2.2 mg/g), and drug release (66.6–98.2% after 24 h) were increased with increasing the concentration of AVH and AA, whereas all above parameters were decreased by increasing the concentration of MBA. The gel fraction decreased from 90.35 to 83.44% by increasing the concentration of AVH and increased from 87.23 to 90.43% and 85.60–89.75% by increasing the concentration of AA and MBA, respectively. The swelling of AVH-co-AA was also examined at pH 7.4 using MRI. The drug release followed zero-order kinetics and super case-II transport mechanism. Acute oral and dermal toxicity studies of AVH-co-AA did not exhibit any hematological, biochemical, or histopathological changes in the rat and rabbit models. Therefore, it can be concluded that AVH-co-AA is a pH-responsive and non-toxic polymeric material to develop sustained-release oral drug delivery systems.

Linseed polysaccharides (LSP) were used to develop a nanoparticle carrier system for the effective delivery of docetaxel (DTX). DTX was loaded in LSP core and further protected by pluronic F-68 shell. Formation, morphology and size distribution of DTX loaded LSP-pluronic nanoparticles (DLP-NPs) were characterized by DLS, FESEM, and PXRD. Spherical shaped DLP-NPs were observed using FESEM image having diameter to be 155 ± 44 nm depending on the drug loading (DL). Encapsulation efficiency (EE) and DL was found in the range from 98 to 78.33% and 0.98–2.35%, respectively. In vitrodrug release studies showed prolong (more than 96 h) and sustain release of DTX from DLP-NPs. The cytotoxicity and cellular uptake study indicated the minimum toxicity of LSP and formulation was found chemotherapeutically effective. Results of the current study demonstrated a potential application of naturally occurring biopolymers in building novel hydrophilic nanoparticle formulation for delivering anticancer therapeutic agents.

Salvia spinosaseeds hydrogel (SSH) was chemically cross-linked with four different concentrations of citric acid (CA), i.e., 1.25%, 2.5%, 5.0%, and 10.0%. The fabrication of CA cross-linked SSH (CA-cl-SSH) was confirmed through Fourier transform infrared spectroscopic analyses. The CA-cl-SSH appeared thermally as stable as SSH. The CA-cl-SSH was found pH-sensitive and exhibited maximum swelling in deionized water (DW) as compared to the buffers of pH 1.2, 6.8, and 7.4 following the order pH 1.2 < pH 6.8 < pH 7.4 < DW. Stimuli-responsive swelling and deswelling (on-off switching) behavior of CA-cl-SSH (2.5% CA) was found reversible at pH 7.4 and 1.2, in DW and normal saline, and DW and ethanol. CA-cl-SSH sustained the release of aceclofenac following the zero-order kinetics and non-Fickian diffusion mechanism. The in vivoradiographic images revealed the presence of CA-cl–SSH–based tablet formulation in GIT for 9 h. Hemocompatibility studies confirmed the non-thrombogenic and non-hemolytic potential of CA-cl-SSH. Acute oral toxicity study presented its safety profile owing to the absence of any mortality and toxic effects. Therefore, it can be concluded that CA-cl-SSH is a novel stimuli-responsive, biocompatible, and non-toxic polysaccharide-based biomaterial having the potential for the development of sustained-release drug delivery system following zero-order kinetics.

Herein, we evaluate the swelling behavior and drug release attributes of Artemisia vulgarishydrogel (AVH) after pressing into tablet form. The swelling response of AVH tablet and AVH based different tablet formulations of caffeine (CF) and levosulpiride (LS) depicted excellent swelling indices at physiological pH of the gastrointestinal tract (GIT), i.e., 6.8 and 7.4. Inverse swelling response of tablets to different molar concentrations of electrolytes, i.e., NaCl and KCl were observed. All tablets showed reproducible on-off swelling/switching behavior in water and ethanol, water and normal saline, and buffer of pH 7.4 and 1.2. The surface morphology of tablets was observed through a SEM and found porous which facilitates the absorption and retention of aqueous media. Real-time swelling behavior of tablet was observed through MRI. A minute amount of drug was released at pH 1.2, whereas, sustained-release at pH 6.8, 7.4 and in deionized water for 12 h was observed proving AVH as a promising biomaterial for developing pH-responsive sustained drug material. CF and LS release followed zero-order release kinetics and super case II transport mechanism. In vivoX-ray study showed the transit of tablet in GIT. Haemocompatibility studies of AVH confirmed its non-thrombogenic and non-hemolytic nature which broaden its application.

Herein, we report on the cross-linking of a glucuronoxylan isolated from Mimosa pudica(MP) seed and its stimuli (biomimetic) responsive properties, i.e., pH, saline and solvent responsive swelling-deswelling. Cross-linked MP hydrogel (CL-MPH) was prepared by esterification of MPH using citric acid (CA) as a cross-linking agent (CLA). Three products of different cross-linking degree were synthesized with different concentrations of CA and characterized by FTIR spectroscopic analysis. CL-MPH (with 5% CA) showed high swelling at pH 6.8, 7.4 and in deionized water while negligible swelling was observed in pH 1.2. This CL-MPH sample exhibited swelling-deswelling (on-off switching) behavior in water to ethanol, water to saline (0.9% NaCl) and basic (pH 7.4) to acidic (pH 1.2) buffer, respectively. Scanning electron microscope (SEM) analysis revealed the presence of interconnected macro-pores in CL-MPH. Tablets prepared with CL-MPH and diclofenac sodium were evaluated for sustained release potential of CL-MPH. Drug release kinetics and release mechanism followed zero-order and non-Fickian diffusion, respectively. Haemocompatibility studies revealed the non-thrombogenic and non-haemolytic potential of CL-MPH. Due to these attributes of CL-MPH; it can find its applications as a pH-sensitive smart biomaterial for targeted/controlled/sustained drug delivery systems.