β-Cyclodextrin-based (IA-co-AMPS) Semi-IPNs as smart biomaterials for oral delivery of hydrophilic drugs: Synthesis, characterization, in-Vitro and in-Vivo evaluation

Edible thermosensitive chitosan/hydroxypropyl β-cyclodextrin hydrogel with natural licoricidin for enhancing oral health: Biofilm disruption and demineralization prevention

Dental caries, a widespread and significantly detrimental health condition, is characterized by demineralization, pain, compromised tooth functionality, and various other adverse effects. Licoricidin (LC), a natural isoflavonoid, demonstrates potent antimicrobial properties for maintaining oral health. However, its practical application is significantly hindered by its limited water solubility and susceptibility to removal within the oral environment. To tackle this issue, we developed a delivery oral system by an edible thermosensitive chitosan- disodium beta-glycerol phosphate pentahydrate (CS/β-GP) hydrogel to load LC/Hydroxypropyl beta-cyclodextrin (HP-β-CD) inclusion complexes. These hydrogels (LC/HP-β-CD/CS/β-GP) could solidify rapidly at oral temperature and sustainably release LC, thereby preventing its rapid clearance from the oral cavity. We confirmed the significant antibacterial activity of this hydrogel against Streptococcus mutans and Staphylococcus aureus. Additionally, the HP-β-CD combination enhanced LC to penetrate bacterial biofilms and inhibit biofilm growth, leading to leakage of cellular proteins and DNA. Additionally, we studied the effect of LC/HP-β-CD/CS/β-GP on intracellular ROS levels and MMP, comprehensively exploring its antimicrobial mechanism. Furthermore, LC/HP-β-CD/CS/β-GP exhibited the ability to inhibit demineralization and demonstrated excellent biocompatibility. In summary, this study presented a safer approach to oral delivering bioactive substances, offering a promising strategy for enhanced oral health and safety.

Ellagic Acid Inclusion Complex-Loaded Hydrogels as an Efficient Controlled Release System: Design, Fabrication and In Vitro Evaluation

Oxidants play a crucial role in the development of oxidative stress, which is linked to disease progression. Ellagic acid is an effective antioxidant with applications in the treatment and prevention of several diseases, since it neutralizes free radicals and reduces oxidative stress. However, it has limited application due to its poor solubility and oral bioavailability. Since ellagic acid is hydrophobic, it is difficult to load it directly into hydrogels for controlled release applications. Therefore, the purpose of this study was to first prepare inclusion complexes of ellagic acid (EA) with hydroxypropyl-β-cyclodextrin and then load them into carbopol-934-grafted-2-acrylamido-2-methyl-1-propane sulfonic acid (CP-g-AMPS) hydrogels for orally controlled drug delivery. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) were used to validate ellagic acid inclusion complexes and hydrogels. There was slightly higher swelling and drug release at pH 1.2 (42.20% and 92.13%) than at pH 7.4 (31.61% and 77.28%), respectively. Hydrogels had high porosity (88.90%) and biodegradation (9.2% per week in phosphate-buffered saline). Hydrogels were tested for their antioxidant properties in vitro against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). Additionally, the antibacterial activity of hydrogels was demonstrated against Gram-positive bacterial strains (Staphylococcus aureus and Escherichia coli) and Gram-negative bacterial strains (Pseudomonas aeruginosa).

Optimisation of a Greener-Approach for the Synthesis of Cyclodextrin-Based Nanosponges for the Solubility Enhancement of Domperidone, a BCS Class II Drug

BCS class II molecules suffer from low oral bioavailability because of their poor permeability and sub-optimal aqueous solubility. One of the approaches to enhance their bioavailability is using cyclodextrin-based nanosponges. This study aimed to optimise and evaluate the feasibility of a microwave-assisted approach to synthesise nanosponges and improve domperidone's solubility and drug delivery potential. In the production process, microwave power level, response speed, and stirring speed were optimised using the Box-Behnken approach. Ultimately, the batch with the smallest particle size and highest yield was chosen. The optimised method of synthesis of the nanosponges resulted in a product yield of 77.4% and a particle size of 195.68 ± 2.16 nm. The nanocarriers had a drug entrapment capacity of 84 ± 4.2% and a zeta potential of -9.17± 0.43 mV. The similarity and the difference factors demonstrated proof-of-concept, showing that the drug release from the loaded nanosponges is significantly greater than the plain drug. Additionally, spectral and thermal characterisations, such as FTIR, DSC, and XRD, confirmed the entrapment of the drug within the nanocarrier. SEM scans revealed the porous nature of the nanocarriers. Microwave-assisted synthesis could be used as a better and greener approach to synthesise these nanocarriers. It could then be utilised to load drugs and improve their solubility, as seen in the case of domperidone.

Study of Hydroxypropyl β-Cyclodextrin and Puerarin Inclusion Complexes Encapsulated in Sodium Alginate-Grafted 2-Acrylamido-2-Methyl-1-Propane Sulfonic Acid Hydrogels for Oral Controlled Drug Delivery

Puerarin has been reported to have anti-inflammatory, antioxidant, immunity enhancement, neuroprotective, cardioprotective, antitumor, and antimicrobial effects. However, due to its poor pharmacokinetic profile (low oral bioavailability, rapid systemic clearance, and short half-life) and physicochemical properties (e.g., low aqueous solubility and poor stability) its therapeutic efficacy is limited. The hydrophobic nature of puerarin makes it difficult to load into hydrogels. Hence, hydroxypropyl-β-cyclodextrin (HP-βCD)-puerarin inclusion complexes (PIC) were first prepared to enhance solubility and stability; then, they were incorporated into sodium alginate-grafted 2-acrylamido-2-methyl-1-propane sulfonic acid (SA-g-AMPS) hydrogels for controlled drug release in order to increase bioavailability. The puerarin inclusion complexes and hydrogels were evaluated via FTIR, TGA, SEM, XRD, and DSC. Swelling ratio and drug release were both highest at pH 1.2 (36.38% swelling ratio and 86.17% drug release) versus pH 7.4 (27.50% swelling ratio and 73.25% drug release) after 48 h. The hydrogels exhibited high porosity (85%) and biodegradability (10% in 1 week in phosphate buffer saline). In addition, the in vitro antioxidative activity (DPPH (71%), ABTS (75%), and antibacterial activity (Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa) indicated the puerarin inclusion complex-loaded hydrogels had antioxidative and antibacterial capabilities. This study provides a basis for the successful encapsulation of hydrophobic drugs inside hydrogels for controlled drug release and other purposes.

Preparation of novel β-CD/P(AA-co-AM) hydrogels by frontal polymerization

In this paper, betaine (Bet) was used as a hydrogen bond acceptor (HBA), and acrylic acid (AA) and acrylamide (AM) were used as hydrogen bond donors (HBD) and mixed to form a deep eutectic solvent (DES). Different concentrations of β-cyclodextrin (β-CD) were dispersed in the DES, and a novel β-CD/P(AA-co-AM) hydrogel was prepared by frontal polymerization (FP). The characteristic structure and morphology of the hydrogels were analyzed using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM), and the properties of the hydrogels were investigated. The results show that the mechanical properties of the hydrogel were improved by β-CD acting as a second cross-linking agent in the polymerization process, thus increasing the cross-link density of the hydrogel. Because the carboxyl groups contained in the acrylic acid dissociate under alkaline conditions, the composite hydrogel shows excellent pH responsiveness under alkaline conditions. Tetracycline hydrochloride was used as a drug model to test the drug loading and drug release performance of the hydrogels. With the increase of β-CD content, the loading capacity of the hydrogels for tetracycline hydrochloride gradually increased. The data of drug release indicated that the hydrogel has good drug delivery performance and has promising applications in drug delivery systems and other areas.

Semi-Interpenetrating Polymer Networks Based on Hydroxy-Ethyl Methacrylate and Poly(4-vinylpyridine)/Polybetaines, as Supports for Sorption and Release of Tetracycline

Semi-interpenetrating polymer networks (semi-IPN) represent a type of polymeric material that has gained increasing amount of interest for their potential biomedical application. This study presents the synthesis, characterization and tetracycline loading/release capacities of semi-IPNs based on hydroxyethyl methacrylate (HEMA) and poly(4-vinylpyridine) (P4VP) or poly (1-vinyl-4-(1-carboxymethyl) pyridinium betaine) (P4VPB-1) and poly (1-vinyl-4-(2-carboxyethyl) pyridinium betaine) (P4VPB-2). The optimization of the semi-IPNs synthesis was achieved by studying the influence of reaction parameters (chemical structure of the cross-linking agent, HEMA:crosslinker ratio, HEMA:linear polymers ratio and the type of solvent of the linear polymers) on the yield of obtaining semi-IPNs and swelling capacity of these systems. Fourier-transform infrared analysis and scanning electron microscopy highlighted the chemical structures and morphologies of the semi-IPNs. The higher swelling capacity was observed in the case of the PHEMA/P4VPB-2 network due to the increased hydrophilicity of P4VPB-2 compared with P4VP and P4VPB-1 polymers. In vitro release studies of tetracycline reveal that the release mechanism is represented by non-Fickian diffusion being controlled by both diffusion and swelling processes. The antimicrobial activity of semi-IPN-tetracycline systems was tested against E. coli and S. aureus, demonstrating that tetracycline is released from the semi-IPN and retains its bactericidal activity. An increased value of the inhibition zone diameter compared with that of tetracycline indicates the possibility that the semi-IPN containing P4VPB-2 also exhibits intrinsic antimicrobial activity due to the presence of the polybetaine in the network structure.

Designing and In Vitro Characterization of pH-Sensitive Aspartic Acid-Graft-Poly(Acrylic Acid) Hydrogels as Controlled Drug Carriers

Acetaminophen is an odorless and white crystalline powder drug, used in the management of fever, pain, and headache. The half-life of acetaminophen is very short; thus, multiple intakes of acetaminophen are needed in a day to maintain a constant pharmacological action for an extended period of time. Certain severe adverse effects are produced due to the frequent intake of acetaminophen, especially hepatotoxicity and skin rashes. Therefore, a drug carrier system is needed which not only prolongs the release of acetaminophen, but also enhances the patient compliance. Therefore, the authors prepared novel aspartic acid-graft-poly(acrylic acid) hydrogels for the controlled release of acetaminophen. The novelty of the prepared hydrogels is based on the incorporation of pH-sensitive monomer acrylic acid with polymer aspartic acid in the presence of ethylene glycol dimethacrylate. Due to the pH-sensitive nature, the release of acetaminophen was prolonged for an extended period of time by the developed hydrogels. Hence, a series of studies was carried out for the formulated hydrogels including sol-gel fraction, FTIR, dynamic swelling, polymer volume analysis, thermal analysis, percent porosity, SEM, in vitro drug release studies, and PXRD analysis. FTIR analysis confirmed the grafting of acrylic acid onto the backbone of aspartic acid and revealed the development of hydrogels. The thermal studies revealed the high thermal stability of the fabricated hydrogels as compared to pure aspartic acid. An irregular surface with a few pores was indicated by SEM. PXRD revealed the amorphous state of the developed hydrogels and confirmed the reduction in the crystallinity of the unreacted aspartic acid by the formulated hydrogels. An increase in gel fraction was observed with the increasing concentration of aspartic acid, acrylic acid, and ethylene glycol dimethacrylate due to the availability of a high amount of free radicals. The porosity study was influenced by the various compositions of developed hydrogels. Porosity was increased due to the enhancement in the concentrations of aspartic acid and acrylic acid, whereas it decreased with the increase in ethylene glycol dimethacrylate concentration. Similarly, the pH-responsive properties of hydrogels were evaluated by dynamic swelling and in vitro drug release studies at two different pH levels (1.2 and 7.4), and a greater dynamic swelling and acetaminophen release were exhibited at pH 7.4 as compared to pH 1.2. An increase in swelling, drug loading, and drug release was seen with the increased incorporation of aspartic acid and acrylic acid, whereas a decrease was detected with the increase in the concentration of ethylene glycol dimethacrylate. Conclusively, the formulated aspartic acid-based hydrogels could be employed as a suitable nonactive pharmaceutical ingredient for the controlled delivery of acetaminophen.

Development, characterization and In-vitro evaluation of guar gum based new polymeric matrices for controlled delivery using metformin HCl as model drug

Currently, hydrogels are considered as ideal biomaterials due to their unique structure and characteristics that facilitates considerable hydrophilicity, swelling, drug loading and release. In this study, we report pH-responsive GG-MAA-AMPS hydrogel delivery system prepared via free radical polymerization technique. Hydrogels were loaded with Metformin HCl as a model drug. Hydrogels were characterized through Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). FTIR confirmed the successful crosslinking of reactants, hydrogel network formation and drug loading. TGA and DSC proved the higher thermal stability of reactants after crosslinking and drug loading. XRD analysis showed decrease in crystallinity of drug after loading into the hydrogels. SEM revealed smooth and glassy appearance of both loaded and unloaded hydrogels. Gel content was increased with increase in concentration of reactants. Drug entrapment was decreased by increasing concentration of GG and AMPS while MAA acted inversely. Hydrogels displayed pH-dependent swelling and drug release behavior being high at pH 6.8 and 7.4 while low at acidic pH (1.2). Oral tolerability in rabbits showed that hydrogels were safe without causing any hematological or histopathological changes in healthy rabbits. Based on the obtained results, GG-MAA-AMPS can be considered as potential carrier for metformin HCl as well as other hydrophilic drugs.

In Vitro and Biological Characterization of Dexamethasone Sodium Phosphate Laden pH-Sensitive and Mucoadhesive Hydroxy Propyl β-Cyclodextrin-g-poly(acrylic acid)/Gelatin Semi-Interpenetrating Networks

The current study reports the fabrication and biological evaluation of hydroxy propyl β-cyclodextrin-g-poly(acrylic acid)/gelatin (HP-β-CD-g-poly(AA)/gelatin) semi-interpenetrating networks (semi-IPN) for colonic delivery of dexamethasone sodium phosphate (DSP). The prepared hydrogels showed pH-dependent swelling and mucoadhesive properties. The mucoadhesive strength of hydrogels increased with an increasing concentration of gelatin. Based on the swelling and mucoadhesive properties, AG-1 was chosen as the optimized formulation (0.33% w/w of gelatin and 16.66% w/w of AA) for further analysis. FTIR revealed the successful development of a polymeric network without any interaction with DSP. SEM images revealed a slightly rough surface after drug loading. Drug distribution at the molecular level was confirmed by XRD. In vitro drug release assay showed pH-dependent release, i.e., a minute amount of DSP was released at a pH of 1.2 while 90.58% was released over 72 h at pH 7.4. The optimized formulation did not show any toxic effects on a rabbit's vital organs and was also hemocompatible, thus confirming the biocompatible nature of the hydrogel. Conclusively, the prepared semi-IPN hydrogel possessed the necessary features, which can be exploited for the colonic delivery of DSP.

Formulation, Characterization, and In Vitro Drug Release Study of β-Cyclodextrin-Based Smart Hydrogels

In this study, novel pH-responsive polymeric β-cyclodextrin-graft-poly(acrylic acid/itaconic acid) hydrogels were fabricated by the free radical polymerization technique. Various concentrations of β-cyclodextrin, acrylic acid, and itaconic acid were crosslinked by ethylene glycol dimethacrylate in the presence of ammonium persulfate. The crosslinked hydrogels were used for the controlled delivery of theophylline. Loading of theophylline was conducted by the absorption and diffusion method. The fabricated network of hydrogel was evaluated by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffractometry (XRD), and scanning electron microscopy (SEM). The crosslinking among hydrogel contents and drug loading by the fabricated hydrogel were confirmed by FTIR analysis, while TGA indicated a high thermal stability of the prepared hydrogel as compared to pure β-cyclodextrin and itaconic acid. The high thermal stability of the developed hydrogel indicated an increase in the thermal stability of β-cyclodextrin and itaconic acid after crosslinking. Similarly, a decrease in crystallinity of β-cyclodextrin and itaconic acid was observed after crosslinking, as evaluated by XRD analysis. SEM revealed an irregular and hard surface of the prepared hydrogel, which may be correlated with strong crosslinking among hydrogel contents. Crosslinked insoluble and uncrosslinked soluble fractions of hydrogel were evaluated by sol–gel analysis. An increase in gel fraction was seen with the increase in compositions of hydrogel contents, while a decrease in sol fraction was observed. Dynamic swelling and dissolution studies were performed in three various buffer solutions of pH 1.2, 4.6, and 7.4, respectively. Maximum swelling and drug release were observed at higher pH values as compared to the lower pH value due to the deprotonation and protonation of functional groups of the hydrogel contents; thus, the pH-sensitive nature of the fabricated hydrogel was demonstrated. Likewise, water penetration capability and polymer volume were evaluated by porosity and polymer volume studies. Increased incorporation of β-cyclodextrin, acrylic acid, and itaconic acid led to an increase in swelling, drug release, drug loading, and porosity of the fabricated hydrogel, whereas a decrease was detected with the increasing concentration of ethylene glycol dimethacrylate. Conclusively, the prepared hydrogel could be employed as a suitable and promising carrier for the controlled release of theophylline.

Designing of pH-Sensitive Hydrogels for Colon Targeted Drug Delivery; Characterization and In Vitro Evaluation

In the current research work, pH-sensitive hydrogels were prepared via a free radical polymerization technique for the targeted delivery of 5-aminosalicylic acid to the colon. Various proportions of chitosan, β-Cyclodextrin, and acrylic acid were cross-linked by ethylene glycol dimethacrylate. Ammonium persulfate was employed as an initiator. The development of a new polymeric network and the successful encapsulation of the drug were confirmed by Fourier transform infrared spectroscopy. Thermogravimetric analysis indicated high thermal stability of the hydrogel compared to pure chitosan and β-Cyclodextrin. A rough and hard surface was revealed by scanning electron microscopy. Similarly, the crystallinity of the chitosan, β-Cyclodextrin, and fabricated hydrogel was evaluated using powder X-ray diffraction. The swelling and drug release studies were performed in both acidic and basic medium (pH 1.2 and 7.4, respectively) at 37 °C. High swelling and drug release was observed at pH 7.4 as compared to pH 1.2. The increased incorporation of chitosan, β-Cyclodextrin, and acrylic acid led to an increase in porosity, swelling, loading, drug release, and gel fraction of the hydrogel, whereas a decrease in sol fraction was observed. Thus, we can conclude from the results that a developed pH-sensitive network of hydrogel could be employed as a promising carrier for targeted drug delivery systems.

Synthesis and In Vitro Evaluation of Aspartic Acid Based Microgels for Sustained Drug Delivery

The main focus of the current study was to sustain the releasing behavior of theophylline by fabricated polymeric microgels. The free radical polymerization technique was used for the development of aspartic acid-co-poly(2-acrylamido-2-methylpropanesulfonic acid) microgels while using various combinations of aspartic acid, 2-acrylamido-2-methylpropanesulfonic acid, and N′,N′-methylene bisacrylamide as a polymer, monomer, and cross-linker, respectively. Ammonium peroxodisulfate and sodium hydrogen sulfite were used as initiators. Characterizations such as DSC, TGA, SEM, FTIR, and PXRD were performed for the fabricated microgels to assess their thermal stability with unreacted polymer and monomer, their surface morphology, the formation of a new polymeric system of microgels by evaluating the cross-linking of functional groups of the microgels’ contents, and to analyze the reduction in crystallinity of the theophylline by fabricated microgels. Various studies such as dynamic swelling, drug loading, sol–gel analysis, in vitro drug release studies, and kinetic modeling were carried out for the developed microgels. Both dynamic swelling and percent drug release were found higher at pH 7.4 as compared to pH 1.2 due to the deprotonation of functional groups of aspartic acid and AMPS. Similarly, sol–gel analysis was performed and an increase in gel fraction was observed with the increasing concentration of microgel contents, while sol fraction was decreased. Conclusively, the prepared carrier system has the potential to sustain the release of the theophylline for an extended period of time.