Fostering kappa (κ)-carrageenan hydrogels with the power of a natural crosslinker: a comparison between tender coconut water and potassium chloride (KCl) for therapeutic applications

This study investigated the potential of tender coconut water as a natural alternative to potassium chloride (KCl) to crosslink κ-carrageenan hydrogels. κ-Carrageenan hydrogels crosslinked with tender coconut water, KCl, and their combination were formulated with diclofenac sodium as model drug, and their morphology, chemical bonding, compressive strength, water uptake capacity, degradation resistance, and cytotoxicity were assessed. The results showed that crosslinking κ-carrageenan hydrogels with both tender coconut water and KCl increased their compressive strength by up to 450%, provided excellent water retention capacity, and resulted in only 5% degradation after 20 days. Scanning electron microscopy revealed that crosslinking the hydrogel with both tender coconut water and KCl compacted its morphological structure, which remained biocompatible when tested with 3T3 cells. Infrared analysis confirmed that incorporated diclofenac sodium remained inert during preparation of the hydrogel matrices. Furthermore, the in vitro release behavior and antimicrobial properties of the hydrogels were assessed. The drug release profile from hydrogels crosslinked with both tender coconut water and KCl was sustained over 24 h. Such hydrogels also showed a unique antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli)-with the activity against E. coli being more pronounced. In conclusion, these results confirm that crosslinking with tender coconut water and KCl is a superior alternative to just with KCl for κ-carrageenan hydrogels.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-025-04254-0.

Curcumin - Bioavailability Enhancement by Prodrug Approach and Novel Formulations

Curcumin is a diverse natural pharmacological agent involved in various signal transduction mechanisms. Therapeutically, this potent molecule faces different challenges and issues related to low bioavailability due to its poor aqueous solubility, less permeability, faster elimination and clearance. Experts in synthetic chemistry and pharmaceuticals are continuously sparing their efforts to overcome these pharmacokinetic challenges by using different structural modification strategies and developing novel drug delivery systems. In this mini-review article, we are focusing on development of curcumin derivatives by different possible routes like conjugation with biomolecules, natural polymers, synthetic polymers, natural products, metal conjugates and co- administration with natural metabolic inhibitors. In addition to that, it was also focused on the preparation of modified formulations such as micelles, microemulsions, liposomes, complexes with phospholipids, micro and nanoemulsions, solid lipid nanoparticles, nano lipid carriers, biopolymer nanoparticles and microgels to improve the pharmacokinetic properties of the curcumin without altering its pharmacodynamics activity. This review helps to understand the problems associated with curcumin and different strategies to improve its pharmacokinetic profile.

Recent Update on Nanoemulsion Impregnated Hydrogel: a Gleam into the Revolutionary Strategy for Diffusion-Controlled Delivery of Therapeutics

Since earlier times, dermatological remedies have been utilized to treat diseases associated with pain, irritation, and skin conditions. Compared to other routes of drug delivery, topical delivery of drugs offers several benefits. Scientists are investigating different alterations in dosage forms in addition to existing topical formulations such as ointments, gels, creams, lotions, and ointments to significantly improve the permeation of drugs and enhance the pharmacological efficacy of medications that are poorly absorbed via the skin. Conventional formulations have a plethora of problems viz. poor absorption, no target specificity, low spreadability, and inadequate bioavailability which leads the researchers toward developing novel formulations like nanoemulsions. The nanoemulsion can enhance the gradient in concentration and thermodynamic movement toward the epidermis and enhance the penetration of its constituents. However, due to its difficult application, nanoemulsion's lower viscosity limited its use in transdermal delivery. Thus, the development of nanoemulsion-based hydrogels has shown to be a successful strategy for removing obstacles from existing drug formulations. The simple application, expedient spreadability, non-stickiness, safety, and effectiveness of nanoemulsion-based hydrogel have led to substantial growth in their research in recent years. This review gives a brief idea about the prevalence of skin diseases, skin as an obstacle for drug delivery, and recent research insights to combat these obstacles. The work highlights the mechanism of drug release via nanoemulsion, hydrogels, and nanoemulsion-based hydrogels with reference to recent research on hydrophobic and hydrophilic drugs.

Encapsulation of cannabidiol in oil-in-water nanoemulsions and nanoemulsion-filled hydrogels: A structure and biological assessment study

HYPOTHESIS

Lipophilic cannabidiol can be solubilized in oil-in water nanoemulsions, which can then be impregnated into chitosan hydrogels forming another colloidal system that will facilitate cannabidiol's release. The delivery from both systems was compared, alongside structural and biological studies, to clarify the effect of the two carriers' structure on the release and toxicity of the systems.

EXPERIMENTS

Oil-in-water nanoemulsions (NEs) and the respective nanoemulsion-filled chitosan hydrogels (NE/HGs) were formulated as carriers of cannabidiol (CBD). Size, polydispersity and stability of the NEs were evaluated and then membrane dynamics, shape and structure of both systems were investigated with EPR spin probing, SAXS and microscopy. Biocompatibility of the colloidal delivery systems was evaluated through cytotoxicity tests over normal human skin fibroblasts. An ex vivo permeation protocol using porcine ear skin was implemented to assess the release of CBD and its penetration through the skin.

FINDINGS

Incorporation of the NEs in chitosan hydrogels does not significantly affect their structural properties as evidenced through SAXS, EPR and confocal microscopy. These findings indicate the successful development of a novel nanocarrier that preserves the NE structure with the CBD remaining encapsulated in the oil core while providing new rheological properties advantageous over NEs. Moreover, NE/HGs proved to be more efficient as a carrier for the release of CBD. Cell viability assessment revealed high biocompatibility of the proposed colloids.

Potential low-calorie model that inhibits free fatty acid release and helps curcumin deliver in vitro: Ca2+-induced emulsion gels from low methyl-esterified pectin with the presence of erythritol

Our previous study showed that pectin de-esterified by high hydrostatic pressure assisted enzymatic method (HHP-pectin) had better Ca2+-induced gel performance and more stable emulsion than those from conventional enzymatic and alkaline methods. In this study, Ca2+-induced emulsion gels were further prepared by HHP-pectin in the presence of erythritol, and their texture properties, moisture distribution, the release of free fatty acids (FFAs) and curcumin were investigated. Results showed that gel strength, gel elasticity, and water cut-off capacity of the prepared emulsion gels significantly increased with Ca2+ concentration increasing. Compared with emulsions, HHP-pectin emulsion gels can significantly decrease FFAs and curcumin release in vitro digestion, especially for samples with better texture properties (higher Ca2+ concentration). This study indicated that Ca2+-induced HHP-pectin emulsion gels prepared with erythritol may provide a new choice for low-calorie foods preparing, and may become a potential alternative model that inhibiting FFAs release and helping fat-soluble nutrients (curcumin) deliver.

Effect of nanoemulsion-loaded hybrid biopolymeric hydrogel beads on the release kinetics, antioxidant potential and antibacterial activity of encapsulated curcumin

Nanoemulsion encapsulated in the hydrogel beads are important entrants for loading hydrophobic active ingredients for enhancing their bioavailability and biological activities relevant in the pharmaceutical, food and cosmetic industries. Herein, we report the formulation of curcumin-loaded nanoemulsion encapsulated in ionotropic hybrid hydrogel beads of alginate, chitosan, gelatin and polyethylene oxide for effective delivery of curcumin. The release behaviour in simulated gastric and intestinal fluids (SGF and SIF) at 37 °C showed faster release in SGF which could be explained on the basis of mesh size, the extent of hydration and the complexation of the curcumin with the Ca2+ ions present within the hydrogel network. The free radical scavenging and antibacterial activities of the released curcumin in SGF were significantly greater than in SIF. This study shows promises of such hybrid systems, ignored so far, for proper encapsulation, protection and delivery of curcumin for the development of functional foods and pharmaceutics. The high structural stability of these nanoemulsion carriers and their effective delivery of curcumin provide a novel and tailored formulation out of existing polymers with plethora of advantages for oral drug delivery. Moreover, this study opens new door for different possibilities to improve the physicochemical characteristics and delivery of bioactive molecules like curcumin.