Neomycin Intercalation in Montmorillonite: The Role of Ion Exchange Capacity and Process Conditions

The study examined the possibility of intercalation of montmorillonite with neomycin in an aqueous drug solution and the factors influencing the effectiveness of this process, such as the ion exchange capacity and process conditions, including the time and temperature of incubation with the drug. X-ray diffractometry (XRD), infrared spectroscopy (FTIR), thermal analysis (DSC/TG), and Zeta potential measurement were used to confirm drug intercalation as well as to investigate the nature of clay-drug interactions. The obtained conjugates with the most favorable physicochemical properties were also tested for antibacterial response against Gram-negative bacteria (Escherichia coli) to confirm that the bactericidal properties of neomycin were retained after intercalation and UV-VIS spectrophotometry was used to examine the kinetics of drug release from the carrier. The results of the conducted research clearly indicate the successful intercalation of neomycin in montmorillonite and indicate the influence of process parameters on the properties of not only the conjugates themselves but also the properties of the intercalated drug, particularly its bactericidal activity. Ultimately, a temperature of 50 °C was found to be optimal for effective drug intercalation and the conjugates obtained within 2 h showed the highest antibacterial activity, indicating the highest potential of the thus-obtained montmorillonite conjugates as neomycin carriers.

Surface Modifications of Superparamagnetic Iron Oxide Nanoparticles with Chitosan, Polyethylene Glycol, Polyvinyl Alcohol, and Polyvinylpyrrolidone as Methylene Blue Adsorbent Beads

Due to the negative impacts the dye may have on aquatic habitats and human health, it is often found in industrial effluent and poses a threat to public health. Hence, to solve this problem, this study developed magnetic adsorbents that can remove synthetic dyes like methylene blue. The adsorbent, in the form of beads, consists of a polymer blend of chitosan, polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, and superparamagnetic iron oxide nanoparticles (average size of 19.03 ± 4.25 nm). The adsorption and desorption of MB from beads were carried out at pH values of 7 and 3.85, respectively. At a concentration of 9 mg/L, the loading capacity and the loading amount of MB after 5 days peaked at 29.75 ± 1.53% and 297.48 ± 15.34 mg/g, respectively. Meanwhile, the entrapment efficiency of MB reached 29.42 ± 2.19% at a concentration of 8 mg/L. The cumulative desorption capacity of the adsorbent after 13 days was at its maximum at 7.72 ± 0.5%. The adsorption and desorption kinetics were evaluated.

Removal of diclofenac sodium from aqueous solution using different ionic liquids functionalized tragacanth gum hydrogel prepared by radiation technique

Diclofenac sodium (DCF) was reported as an important emerging environmental pollutant and its removal from wastewater is very urgent. In this study, different alkyl substituted ionic liquids (1-alkyl -3-vinyl- imidazolium bromide [CnVIm]Br, n = 4, 6, 8, 10, 12) functionalized tragacanth gum (TG-CnBr) are prepared by radiation induced grafting and crosslinking polymerization. The adsorption behaviors of ionic liquids functionalized tragacanth gum for diclofenac sodium from aqueous solutions are examined. The adsorption capacity of TG-CnBr for diclofenac sodium increases with the increasing of alkyl chain length of the imidazolium cation and the hydrophobicity of the hydrogels. The maximum adsorption capacity by TG-C12Br for diclofenac sodium at 30, 40 and 50 °C were 327.87, 310.56 and 283.29 mg/g, respectively. The adsorption of TG-C12Br towards diclofenac sodium was little decreased with NaCl increasing. The removal efficiency was still remained 94.55 % within 5 adsorption-desorption cycles by 1 M HCl. Also, the adsorption mechanism including electrostatic attraction, hydrophobic interaction, hydrogen bonding, and π - π interaction was proposed.

Recent advances in natural nanoclay for diagnosis and therapy of cancer: A review

Cancer is still one of the deadliest diseases, and diagnosing and treating it effectively remains difficult. As a result, advancements in earlier detection and better therapies are urgently needed. Conventional chemotherapy induces chemoresistance, has non-specific toxicity, and has a meager efficacy. Natural materials like nanosized clay mineral formations of various shapes (platy, tubular, spherical, and fibrous) with tunable physicochemical, morphological, and structural features serve as potential templates for these. As multifunctional biocompatible nanocarriers with numerous applications in cancer research, diagnosis, and therapy, their submicron size, individual morphology, high specific surface area, enhanced adsorption ability, cation exchange capacity, and multilayered organization of 0.7-1 nm thick single sheets have attracted significant interest. Kaolinite, halloysite, montmorillonite, laponite, bentonite, sepiolite, palygorskite, and allophane are the most typical nanoclay minerals explored for cancer. These multilayered minerals can function as nanocarriers to effectively carry a variety of anticancer medications to the tumor site and improve their stability, dispersibility, sustained release, and transport. Proteins and DNA/RNA can be transported using nanoclays with positive and negative surfaces. The platform for phototherapeutic agents can be nanoclays. Clays with bio-functionality have been developed using various surface engineering techniques, which could help treat cancer. The promise of nanoclays as distinctive crystalline materials with applications in cancer research, diagnostics, and therapy are examined in this review.

Bentonite as a water-insoluble amorphous solid dispersion matrix for enhancing oral bioavailability of poorly water-soluble drugs

Bentonite (BT), an orally administrable natural clay, is widely used for medical and pharmaceutical purposes due to its unique properties, including swelling, adsorption and ion-exchange. However, its application as a matrix of amorphous solid dispersion (ASD) formulations is rarely reported, despite the fact that drugs can adsorb to BT in an amorphous state. The objective of this study was to explore the feasibility of BT as a water-insoluble ASD matrix for enhancing the oral bioavailability of poorly water-soluble drugs, including sorafenib (SF). We prepared a novel BT-based ASD of an SF-BT composite (SFBTC) by adsorbing SF onto BT under acidic conditions using the ionic interaction between cationic SF and negatively charged BT. Scanning electron microscopy (SEM), powder X-ray diffractometry (pXRD), and differential scanning calorimetry (DSC) analyses revealed that SF adsorbed to BT in an amorphous state at SF:BT ratios from 1:3 to 1:10. In pharmacokinetic studies in rats, SFBTC (1:3) significantly improved the oral bioavailability of SF, and the AUClast of SFBTC (1:3) was 3.3-fold higher than that of NEXAVAR®, a commercial product of SF. An in vitro release study under sink conditions revealed that SFBTC (1:3) completely released SF in a pH-dependent manner, while a nonsink condition study indicated the generation of supersaturation under intestinal pH conditions. A kinetic solubility study showed that the release of SFBTC (1:3) followed the diffusion-controlled mechanism, which is a typical characteristic of water-insoluble matrix-based ASDs. The pharmacokinetic studies of drug-BT composites of various drugs belonging to BCS class II indicated that the pKa value of the adsorbed drugs is one of the most important factors determining their dissolution and oral bioavailability. These results suggest that BT could be a promising water-insoluble ASD matrix for improving the oral bioavailability of poorly water-soluble drugs, including SF.

Formulation and evaluation of taste-masked oral disintegrating tablet containing tolterodine-loaded montmorillonite

Background and purpose

The present study aimed to obtain a taste-masked oral disintegrating tablet (ODT) containing tolterodine tartrate (TT) intercalated into montmorillonite (MMT).

Experimental approach

The TT-MMT hybrid was prepared by ion exchange reaction. The effect of the initial concentration of TT, MMT, temperature, and pH on the encapsulation efficiency (EE) % of the drug in MMT was evaluated. The selected TT-MMT hybrid was characterized by X-ray diffraction (XRD), Fourier transforms infrared (FTIR), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Then, the optimized TT-MMT hybrid was incorporated in the ODT prepared by direct compression method and taste-masking assessment performed by a human test panel.

Findings/Results

The EE% of TT was in the range of 22.67 to 71.06% in different formulations. It was found that increases in MMT concentration significantly increased EE%. DSC and XRD studies indicated that the TT was intercalated in the MMT interlayer space in an amorphous or molecular state. In-vitro release studies at pH 6.8 showed that the amount of the drug released from the TT-MMT hybrid was negligible for the first 3 min. The post-compression of ODT also showed satisfactory results in terms of friability, hardness, disintegration time, and taste.

Conclusion and implications

MMT-ODT could be a suitable vehicle for the taste masking of TT, with the potential for use in patients with swallowing problems.

Biodegradable Gg-cl-poly(NIPAm-co-AA)/-o-MWCNT based hydrogel for combined drug delivery system of metformin and sodium diclofenac: in vitro studies

In the present study Gg-cl-poly(NIPA-co-AA) and Gg-cl-poly(NIPA-co-AA)/-o-MWCNT hydrogels were synthesized using free radical polymerization. We looked into whether combining metformin with diclofenac, a nonsteroidal anti-inflammatory drug (NSAID), would be effective in examining complex formation and analysing the types and intensities of complexes that could result from metformin-diclofenac interactions. The interaction of metformin and diclofenac was studied in vitro at various pH levels and body temperatures. The structure and morphology of the produced hydrogel were characterised using FTIR spectra, SEM analysis, and drug loading tests. As a model drug, the hydrogel was loaded with metformin hydrochloride and sodium diclofenac (DS), and the medicines were released pH-dependently. To explore the drug release kinetics and mechanism, the zero order and first order kinetic models, the Korsemeyar-Peppas model, the Higuchi model, and the Hixson-Crowell model have all been employed. Drug release studies revealed notable characteristics in connection to physiologically predicted pH values, with a high release rate at pH = 9.2. At pH = 9.2, however, both metformin and sodium diclofenac exhibited a Fickian mechanism. Combination treatment may reduce the effective dose of a single drug and hinder metabolic rescue mechanisms. More study is needed to detect any negative effects on individuals.

Design of ophthalmic micelles loaded with diclofenac sodium: effect of chitosan and temperature on the block-copolymer micellization behaviour

Diclofenac sodium 0.1% is a commonly used NSAID with well-documented clinical efficacy in reducing postoperative inflammation; however, its corneal tolerability and ophthalmic tissue bioavailability require further improvement. Advanced micellar delivery systems composed of block-copolymers and chitosan showing fine balance between the mucoadhesion and mucus permeation, capable to slip through the mucus barrier and adhere to the epithelial ocular surface, may be used to tackle both challenges. The aggregation behaviour of the block-copolymers in the presence of different additives will dramatically influence the quality attributes like particle size, particle size distribution, drug-polymer interaction, zeta potential, drug incorporation, important for the delicate balance among mucoadhesion and permeation, as well as safety and efficacy of the ophthalmic micelles. Therefore, quality by design approach and D-optimal experimental design model were used to create a pool of useful data for the influence of chitosan and the formulation factors on the block copolymer's aggregation behaviour during the development and optimization of Diclofenac loaded Chitosan/Lutrol F127 or F68 micelles. Particle size, polydispersity index, dissolution rate, FTIR and DSC studies, NMR spectroscopy, cytotoxicity, mucoadhesivity, mucus permeation studies, and bioadhesivity were assessed as critical quality attributes. FTIR and DSC studies pointed to the chaotropic effect of chitosan during the micelle aggregation. Mainly, Pluronic F68 micellization behaviour was more dramatically affected by the presence of chitosan, and self-aggregation into larger micelles with high polydispersity index was favoured at higher chitosan concentration. The optimized formulation with highest potential for ophthalmic delivery of diclofenac sodium, good cytotoxicity profile, delicate balance of the mucoadhesivity, and mucus permeation was in the design space of Chitosan/Lutrol F127 micelles.

Preclinical developments of natural-occurring halloysite clay nanotubes in cancer therapeutics

The natural world holds useful resources that can be exploited to design effective therapeutic approaches. Ready-to-use tubular nanoclays, such as halloysite clay nanotubes (HNTs), are widely available, cost-effective, and sustainable submicron crystalline materials that have been showing great potential towards chronic multifactorial and malignant diseases, standing out as a promising anticancer nanotherapeutic strategy. Currently, several preclinical studies have reported the application of HNTs in cancer research, diagnosis, monitoring, and therapeutics. This groundbreaking review highlights the preclinical knowledge hitherto collected concerning the application of HNTs towards cancer therapy. Despite their reproducibility issues, HNTs were used as nanoarchitectonic platforms for the delivery of conventional chemotherapeutic, natural-occurring, biopharmaceutical, and phototherapeutic anticancer agents in a wide range of in vitro and in vivo solid cancer models. Overall, in different types of cancer mice models, the intratumoral and intravenous administration of HNTs-based nanoplatforms induced tumor growth inhibition without causing significant toxic effects. Such evidence raises a relevant question: does the therapeutic benefit of the parenteral administration of HNTs in cancer outweigh their potential toxicological risk? To answer this question further long-term absorption-distribution-metabolism-excretion studies in healthy and cancer animal models need to be performed. In cancer therapeutics, HNTs are envisaged as promising platforms for cancer multi-agent therapy, enabling the combination of different therapeutic modalities. Furthermore, HNTs might constitute suitable nanotheranostic platforms. Nevertheless, to confirm the potential and safety of the application of HNTs as nanodelivery systems for cancer therapy, it is necessary to perform in-depth in vivo pharmacokinetics and pharmacodynamic studies to further the translation to clinical trials.

Clay nanoparticles as pharmaceutical carriers in drug delivery systems

INTRODUCTION

Clay minerals are a class of silicates with chemical inertness, colloid, and thixotropy, which have excellent physicochemical properties, good biocompatibility, low toxicity, and have high application potential in biomedical fields. These inorganic materials have been widely used in pharmaceutical excipients and active substances. In recent years, nanoclay mineral materials have been used as drug vehicles for the delivery of a variety of drugs based on their broad specific surface area, rich porosity, diverse morphology, good adsorption performance, and high ion exchange capacity.

AREAS COVERED

This review introduces the structures, properties, and applications of various common natural and synthetic nanoclay materials as drug carriers. Natural nanoclays have different morphologies including nanoplates, nanotubes, and nanofibers. Synthetic materials have controllable sizes and flexible structures, where mesoporous silica nanoparticles, laponite, and imogolite are typical ones. These inorganic nanoparticles are often linked to polymers to form multifunctional drug delivery systems for better pharmaceutical performance.

EXPERT OPINION

The clay nanomaterials have typical properties, including enhanced solubility of insoluble drugs, targeting therapeutic sites, controlled release, and stimulation of responsive drug delivery systems.

Efficient removal of diclofenac and cephalexin from aqueous solution using Anthriscus sylvestris-derived activated biochar

The objective of this study was to investigate the adsorption of diclofenac (DF) and cephalexin (CPX) by Anthriscus sylvestris-derived activated biochar. The raw biochar (R-BC) and activated biochar (ACT-B) were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and elemental analyses techniques to obtain information regarding the morphology, functional groups and elements of the adsorbents. Batch studies were carried out to examine the effect of various operational parameters. The maximum adsorption capacity of ACT-B was 392.94 mg g^-1 for DF and 724.54 mg g^-1 for CPX. The removal of DF and CPX was influenced by temperature and the co-existing ions. The kinetic data fitted well with the pseudo-second-order kinetic model, whereas the isotherm data showed the best correlation with Langmuir isotherm model. Electrostatic adsorption, hydrophobic interaction and π-π bonding play a key role in adsorption of both adsorbates by ACT-B. Additionally, column studies were conducted using ACT-B at different flow rates and different concentrations of DF and CPX to investigate the practical applicability of ACT-B in removal of the target contaminants. Thus, this study provides a feasible approach to synthesize activated biochar that can minimize pharmaceuticals pollution in water bodies.

Adsorption site-dependent transport of diclofenac in water saturated minerals and reference soils

Use of reclaimed water for irrigation is a main way for pharmaceutical compounds such as diclofenac getting into the soil environment. However, the role of minerals, especially iron oxides, in the diclofenac adsorption to soils with low soil organic matter (SOM) is still in the lack of evaluation. In this study, adsorption of diclofenac onto six minerals (five nature minerals-hematite, goethite, magnetite, kaolinite and aluminium oxide and one engineered mineral-activated aluminia) and five reference soils was investigated by column chromatography. Adsorption of diclofenac onto minerals and soils was totally reversible and interactions such as H-bonding were the primary mechanisms. Adsorption affinity of iron oxides was much higher than that of nature silicon and aluminum oxides. Diclofenac tended to be adsorbed by mineral surface -OH groups with high thermodynamic stability, which were dehydroxylated at high temperature. Compared with the SOM-dominated sorption of naphthalene, adsorption of diclofenac onto soils was controlled by bonding with surface -OH groups of iron oxides. Adsorption coefficients of diclofenac onto soils can be well predicted by contents of extracted Fe by diethylenetriamine pentaacetic acid (DTPA) instead of total iron oxides contents, suggesting that the bonding was adsorption site-dependent. These findings highlighted the importance of iron oxides in the adsorption of diclofenac (an anionic pharmaceutical compound) in soils with relatively low SOM (e.g., 1.03-3.45%). It also indicated that contents of effective surface -OH groups and DTPA-Fe were the promising parameters to develop the predictive models for diclofenac adsorption onto minerals and soils, respectively.

Green-synthesized copper nano-adsorbent for the removal of pharmaceutical pollutants from real wastewater samples

The release of Non-Steroidal Anti-Inflammatory drugs (NSAIDs) such as Ibuprofen (Ibu), Naproxen (Nab) and Diclofenac (Dic) to the aquatic system cause serious environmental problems. In this study, green-synthesized copper nanoparticles (Cu NPs) have been used as nano-adsorbent for the removal of Ibu, Nab, and Dic from wastewater samples. Formation of Cu NPs was confirmed by different analytical techniques. The adsorption parameters such as temperature, pH, adsorbate concentration, adsorbent dose and contact time were studied. The best removal results were obtained at these conditions: temperature 298 K, pH = 4.5, 10.0 mg Cu NPs, 60 min. At these conditions, the removal percentage of Ibu, Nap, and Dic were found to be 74.4, 86.9 and 91.4% respectively. The maximum monolayer adsorption capacities were calculated as 36.0, 33.9 and 33.9 mg/g for Dic, Nap, and Ibu respectively. The kinetic studies conducted that the sorption process obeyed the second order kinetic model, while the thermodynamic results revealed that the adsorption process was spontaneous, endothermic (+23.8, +40.8 and +38.3 kJ/mol for Ibu, Nap and Dic respectively). The results revealed that green-synthesized copper nano-adsorbent may be used for the removal of the anti-inflammatory drugs from real wastewater efficiently.

Chitosan/beidellite nanocomposite as diclofenac carrier

Chitosan (CS) and purified sodium beidellite (Na-Bd) were used to obtain a nanocomposite able to carry anionic pharmaceutical ingredients. Diclofenac sodium (DS) was chosen as a model drug and was loaded by intercalation solution technique. Solid state characterization of the resultant hybrids was performed, including X-ray diffraction, Fourier transformed infrared spectroscopy, Thermal analysis and high resolution transmission electron microscopy coupled with energy dispersive X-Ray analysis. Drug loading capacity and encapsulation efficiency were quantified by measuring equilibrium concentration by UV-Vis spectroscopy at 276 nm. Solid-state characterization of the samples confirmed both chemical and physical interaction of DS with the nanocomposites. High drug loading along with a modified cumulative release of the drug in simulated intestinal fluid was obtained. The developed clay/polymer hybrids can act as potential candidates for the design of modified dosage forms of anionic drugs.

Adsorption of diclofenac on a magnetic adsorbent based on maghemite: experimental and theoretical studies

Maghemite nanoparticles synthesized by one-pot synthesis adsorb diclofenac efficiently.

Application of montmorillonite in bentonite as a pharmaceutical excipient in drug delivery systems

Montmorillonite is a multifunctional clay mineral and a major component of bentonite. Montmorillonite has been used in various industrial and pharmaceutical fields due to its unique characteristics, which include swelling and adsorption. The high adsorption capacity of montmorillonite contributes to increase drug entrapment and sustained-release of drugs. Montmorillonite generally sustains drug release in many formulations by strongly adsorbing to the drug. In addition, montmorillonite enhances the dissolution rate and bioavailability of hydrophobic drugs. Moreover, montmorillonite was applied to form composites with other polymer-based delivery systems. Thus, montmorillonite could be applied to formulate diverse drug delivery systems to control and/or improve the pharmaceutical properties of drugs, including solubility, dissolution rate, and absorption. In this review, perspectives of applying montmorillonite as a pharmaceutical excipient in drug delivery systems are discussed.