The mechanism of bensulfuron-methyl complexation with β-cyclodextrin and 2-hydroxypropyl-β-cyclodextrin and effect on soil adsorption and bio-activity

Bioavailability enhancement of sildenafil citrate via hydrogel-forming microneedle strategy in combination with cyclodextrin complexation

Sildenafil citrate (SIL) as a first-line treatment for erectile dysfunction is currently reported to have poor solubility and bioavailability. Moreover, SIL undergoes first-pass metabolism when taken orally and its injection can lead to discomfort. In this study, we introduce a novel transdermal delivery system that integrates hydrogel-forming microneedles with the inclusion complex tablet reservoir. The hydrogel-forming microneedle was prepared from a mixture of polymers and crosslinkers through a crosslinking process. Importantly, the formulations showed high swelling capacity (>400 %) and exhibited adequate mechanical and penetration properties (needle height reduction < 10 %), penetrating up to five layers of Parafilm® M (assessed to reach the dermis layer). Furthermore, to improve the solubility of SIL in the reservoir, the SIL was pre-complexed with β-cyclodextrin. Molecular docking analysis showed that SIL was successfully encapsulated into the β-cyclodextrin cavity and was the most suitable conformation compared to other CD derivatives. Moreover, to maximize SIL delivery, sodium starch glycolate was also added to the reservoir formulation. As a proof of concept, in vivo studies demonstrated the effectiveness of this concept, resulting in a significant increase in AUC (area under the curve) compared to that obtained after administration of pure SIL oral suspension, inclusion complex, and Viagra® with relative bioavailability > 100 %. Therefore, the approach developed in this study could potentially increase the efficacy of SIL in treating erectile dysfunction by being non-invasive, safe, avoiding first-pass metabolism, and increasing drug bioavailability.

Fabricating Polymer/Surfactant/Cyclodextrin Hybrid Particles for Possible Nose-to-Brain Delivery of Ropinirole Hydrochloride: In Vitro and Ex Vivo Evaluation

Ropinirole is a non-ergolinic dopamine agonist used to manage Parkinson's disease and it is characterized by poor oral bioavailability. This study aimed to design and develop advanced drug delivery systems composed of poloxamer 407, a non-ionic surfactant (Tween 80), and cyclodextrins (methyl-β-CD or hydroxy-propyl-β-CD) for possible brain targeting of ropinirole after nasal administration for the treatment of Parkinson's disease. The hybrid systems were formed by the thin-film hydration method, followed by an extensive physicochemical and morphological characterization. The in vitro cytotoxicity of the systems on HEK293 cell lines was also tested. In vitro release and ex vivo mucosal permeation of ropinirole were assessed using Franz cells at 34 °C and with phosphate buffer solution at pH 5.6 in the donor compartment, simulating the conditions of the nasal cavity. The results indicated that the diffusion-controlled drug release exhibited a progressive increase throughout the experiment, while a proof-of-concept experiment on ex vivo permeation through rabbit nasal mucosa revealed a better performance of the prepared hybrid systems in comparison to ropinirole solution. The encouraging results in drug release and mucosal permeation indicate that these hybrid systems can serve as attractive platforms for effective and targeted nose-to-brain delivery of ropinirole with a possible application in Parkinson's disease. Further ex vivo and in vivo studies to support the results of the present work are ongoing.

Stability improvement of UV-filter between methoxy cinnamic acid derivatives and cyclodextrins inclusion complexes based on DFT and TD-DFT investigations

Structures and UV-vis absorption spectra of the host-guest interaction of the methoxy cinnamic acid (MCA) derivatives and cyclodextrins (CDs) were performed by using the density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. All geometries of MCA derivatives (4-MCA, 245-MCA, 246-MCA), three types of CD (αCD, βCD, γCD), and five host-guest inclusion complexes between MCA and CD consisting of 4-MCA/αCD (1), 4-MCA/βCD (2), 245-MCA/βCD (3), 246-MCA/βCD (4), and 246-MCA/γCD (5) were fully optimized by using the M06-2X/6-31G (d,p) levels of theory. Two orientations (A and B) of the MCA guest molecule were considered. Upon examining the optimized geometry, five complexes of the methoxy cinnamic acid molecules are located inside the cavity of CD. Orientation B was more stable than orientation A because of the stronger intermolecular hydrogen bonds between the hydroxyl group of CD and the carboxylic group of MCA. The results indicated that the intermolecular hydrogen bond is mainly the driving force of formation between methoxy cinnamic acid and cyclodextrins. To reveal the host-guest interaction that is relevant to UV-filter compounds, the UV-vis absorption spectra were performed using TD-DFT calculations. The obtained results confirmed that orientation B is the most stable orientation and can absorb in both UVB and UVA regions which is similar to the parent MCA. Therefore, this knowledge will bring to understand the host-guest interaction between methoxy cinnamic acid and cyclodextrin complexes. The theoretical results are expected to provide valuable information for improving the stability of further UV-filter compounds.

A new series of acylhydrazones derived from metribuzin with modulated herbicidal activity

This paper reports the preparation and herbicidal evaluation of a small library of acylhydrazones based on the synthetic herbicide metribuzin. The hydrazone linkage easily obtained by reaction of metribuzin with aliphatic and aromatic aldehydes, masks efficiently the exocyclic amino group, thereby altering significantly H-bonding with the receptor and increasing the lipophilicity relative to the parent herbicide. The structures of all compounds, including key stereochemical issues on conformation and E/Z configuration around the C[bond, double bond]N bond were thoroughly elucidated by spectroscopic methods, and unambiguously corroborated by X-ray diffraction analysis. The herbicidal assays using an aliphatic and an aromatic acylhydrazone were performed on tomato and rapeseed plants grown in greenhouse. Our results demonstrate, regardless of rate application, that such acylhydrazone formulations do not alter the selectivity of metribuzin. Moreover, the herbicide activity was even higher in the alkyl derivative than that achieved by commercial metribuzin, thus suggesting that this substance can be applied with no need of combination with chemical coadjuvants, unlike most formulations of commercially available herbicides. Therefore, the study shows the promising effect of chemical derivatization of a common herbicide as metribuzin, to improve the herbicide activity without compromising selectivity, and allowing the farmers its use in crop protection safely and effectively.

A general supramolecular adjuvant for pesticides based on host-guest recognition

BACKGROUND

Pesticides are indispensable in agriculture and can effectively improve the yields and quality of crops. Due to their weak water solubility, most pesticides need to be dissolved by adding solubilizing adjuvants. In this work, based on molecular recognition of the macrocyclic host, we developed a novel supramolecular adjuvant, called sulfonated azocalix[4]arene (SAC4A), which significantly improves the water solubility of pesticides.

RESULTS

SAC4A presents multiple advantages, including high water solubility, strong binding affinity, universality, and simple preparation. SAC4A showed an average binding constant value of 1.66 × 105  M-1 for 25 pesticides. Phase solubility results indicated that SAC4A increased the water solubility of pesticides by 80-1310 times. The herbicidal, fungicidal, and insecticidal activities of supramolecular formulations were found to be superior to those of technical pesticides, and the herbicidal effects were even better than those of commercial formulations.

CONCLUSION

Overall results revealed the potential of SAC4A to improve the solubility and effectiveness of pesticides, providing a new development idea for the application of adjuvants in agriculture. © 2023 Society of Chemical Industry.

Insights from molecular dynamics and DFT calculations into the interaction of 1,4-benzodiazepines with 2-hydroxypropyl-βCD in a theoretical study

This study delves into the interaction between benzodiazepine (BZD) drugs and 2-hydroxypropyl-β-cyclodextrin (2HPβCD), a cyclodextrin (CD) known to improve drug delivery and enhance therapeutic outcomes. We find that the 2HPβCD's atoms become more rigid in the presence of chlordiazepoxide (CDP), clonazepam (CLZ), and diazepam (DZM), whereas they become more flexible in the presence of nordazepam (NDM) and nitrazepam (NZP). We also investigated the structure of 2HPβCD and found that loading these drugs increases both the area and volume of the 2HPβCD cavity, making it more suitable for drug delivery. Moreover, this research found that all drugs exhibited negative values for the binding free energy, indicating thermodynamic favorability and improved solubility. The binding free energy order of the BZDs was consistent in both molecular dynamics and Monte Carlo methods, with CDP and DZM having the highest affinity for binding. We also analyzed the contribution of different interaction energies in binding between the carrier and the drugs and found that Van der Waals energy is the primary component. Our results indicate that the number of hydrogen bonds between 2HPβCD/water slightly decreases in the presence of BZDs, but the hydrogen bond's quality remains constant.

Characterization of New Polymer Material of Amino-β-Cyclodextrin and Sodium Alginate for Environmental Purposes

The β-cyclodextrin polymer (PβCD) cross-linked with pyromellitic dianhydride (PD) and functionalized with an amino group (PAβCD) was introduced into a matrix made of sodium alginate (SA). Scanning electron microscopy (SEM) images showed a homogeneous surface of the composite material. Infrared spectroscopy (FTIR) testing of the PAβCD confirmed polymer formation. The tested polymer increased its solubility relative to the polymer without the amino group. Thermogravimetric analysis (TGA) confirmed the stability of the system. Differential scanning calorimetry (DSC) showed the chemical binding of PAβCD and SA. Gel permeation chromatography (GPC-SEC) showed high cross-linking of PAβCD and allowed for accurate determination of its weight. The formation of the composite material such as PAβCD introduced into a matrix made of sodium alginate (SA) has several potential environmental implications, including the use of sustainable materials, reduced waste generation, reduced toxicity, and improved solubility.

Study of the inclusion complexes formed between 4-phenylbutyrate and α-, β- and γ-cyclodextrin in solution and evaluation on their taste-masking properties

OBJECTIVES

4-Phenylbutyrate (PB), which is used in the management of urea cycle disorders, has an unpleasant taste leading to poor patient compliance. Existing PB formulations though helpful, have some limitations in their use. This study reports on attempts to mask this unpleasant taste by complexing PB with cyclodextrins (CDs) to improve patient compliance.

METHODS

α, β and γCD were used as CDs. Phase solubility studies, circular dichroism, 1H-NMR spectroscopy, including ROESY, and molecular modelling were used to investigate and characterize the PB-CD interactions in solution. The taste-masking effect of the CDs was evaluated using in vitro taste sensor measurements.

KEY FINDINGS

PB interacts with α, β and γCD in solution to form 1:1, 1:1 and 1:2 CD: PB inclusion complexes, respectively, with stability constants in the order αCD > βCD > γCD. Taste evaluation revealed that the CDs significantly mask the taste of PB through the formation of the inclusion complexes. Notably, αCD masked the bitter taste of PB to 30% of the initial taste at a 1:1 molar ratio.

CONCLUSION

αCD significantly masks the unpleasant taste of PB in solution and can be used to formulate PB to address the limitations of existing formulations and improve patient compliance and quality of life.

Alternative Methotrexate Oral Formulation: Enhanced Aqueous Solubility, Bioavailability, Photostability, and Permeability

The poor aqueous solubility and/or permeability and thereby limited bioavailability largely restricts the pharmaco-therapeutic implications of potent anticancer drugs such as methotrexate (MTX). Furthermore, MTX’s inherently unstable nature makes it difficult to develop a viable oral formulation. In this study we developed the spray-dried amorphous inclusion complexes of MTX with native β-cyclodextrin (β-CD) and its derivatives, namely HP-β-CD, M-β-CD, and DM-β-CD to enhance the aqueous solubility, photostability, permeability, and oral bioavailability of MTX in rats. Our findings show that the 1:1 stoichiometry ratio of MTX and CDs improves the aqueous solubility, stability, and pharmacokinetic profiles of the drug, the better results being obtained particularly with DM-β-CD as a host, which has a higher complexation ability with the drug compared to other β-CDs. Specifically, the pharmacokinetic analysis demonstrated 2.20- and 3.29-fold increments in AUC and Cmax, respectively, in comparison to free MTX. Even though the absorptive permeability of MTX and MTX/DM-β-CD inclusion complexes was similar, the efflux of the absorbed MTX from ICs was significantly lower compared to the free MTX (4.6- vs. 8.0-fold). Furthermore, the physicochemical characterization employing SEM, DSC, and PXRD confirmed the transformation of crystalline MTX to its amorphous state. In solution, ¹H NMR studies revealed that MTX embedded into the DM-β-CD cavity resulting in both H-3 and H-5 chemical shifts implied the presence of intermolecular interaction between the drug and CD moiety. It was, therefore, evident that an MTX IC could be a successful oral formulation technique, preventing MTX degradation and enhancing its pharmacologically relevant properties.

Cyclodextrin Dispersion of Mebendazole and Flubendazole Improves In Vitro Antiproliferative Activity

Mebendazole and flubendazole are antihelmintic drugs that have re-entered the research spotlight due to their exhibited anticancer effects, thus making them strong candidates as repurposed drugs. However, these benzimidazole derivatives exhibit poor solubility in water and various organic solvents, which limits their bioavailability. With the aim of obtaining an improved drug solubility and increased biological effect, mebendazole and flubendazole were complexed with 2-hydroxypropyl-β-cyclodextrin (HPBCD). The binary 1:1 conjugates were physicochemically evaluated by X-ray diffraction, thermal analysis, and FTIR spectroscopy, revealing the formation of physical mixtures. The increased aqueous solubility of the binary 1:1 conjugates vs. pure benzimidazole compounds was demonstrated by performing dissolution tests. The in vitro antiproliferative activity of mebendazole and flubendazole, as well as their combination with HPBCD, was tested on two cancer cell lines, human melanoma—A375 and pulmonary adenocarcinoma—A549 by the MTT assay. The cytotoxic activity manifested in a dose-dependent manner while the presence of HPBCD increased the antiproliferative activity against the targeted cells. Treatment of A375 and A549 cell lines with the binary conjugates induced a significant inhibition of mitochondrial respiration, as revealed by high-resolution respirometry studies. Molecular docking analysis showed that one of the mechanisms related to MEB and FLU cytotoxic activity may be due to the inhibition of MEK/ERK proteins.

Tyrosine-Derived Novel Benzoxazine Active in a Rat Syngenic Mammary Tumor Model of Breast Cancer

In continuing efforts of improving benzoxazepine derivatives as an anti-breast cancer agent, a new chemical entity, benzoxazine, was designed from scaffold morphing. Structure-activity relationship studies revealed that H, -OMe, -CF₃, and -F were well tolerated on R₁ and R₂ positions of ring A, and R² as -CH₂CH₂N(CH₂)₄ (N-ethyl pyrrolidine) and -CH₂CH₂N(CH₂)₅ (N-ethyl piperidine) chains on ring D increased activities (Series B, Figure 3). 13d selected as a lead compound (IC₅₀: 0.20 to 0.65 μM) induces apoptosis, cell cycle arrest, and loss of mitochondrial membrane potential in breast cancer cells. Compound 13d was formulated into 13d-f using cyclodextrin to improve its solubility for a pharmacokinetic, in vivo efficacy study. Both 13d and 13d-f regressed tumor growth at concentrations of 5 and 20 mg/kg better than tamoxifen without any mortality in a rat syngenic mammary tumor model. Collectively, our data suggest that tyrosine-derived novel benzoxazine 13d could be a potential lead for the treatment of breast cancer and hence deserve further in-depth studies.

Pesticide remediation with cyclodextrins: a review

The aim of this review is to highlight and provide an update on the current development of pesticide remediation methods, focusing on the utilization of different cyclodextrin (CD) molecules. Because of less environmental impact and non-toxic nature, CDs are beneficial for pesticide remediation, reducing environmental risk and health hazards. They are advantageous for the removal of pesticides from contaminated areas, as well as for better pesticide formulation and, posing significant effects on the hydrolysis or degradation of pesticides. The review focuses on the current trend and innovations regarding the methods and strategies employed for using CDs in designing pesticide remediation. Nowadays, in addition to the conventional experimental techniques, molecular simulation approaches are significantly contributing to the study of such phenomena and hence are recognized as a widely used tool.

1-Octyl-3-methylimidazolium hexafluorophosphate-functionalised magnetic poly β-cyclodextrin for magnetic solid-phase extraction ofpyrethroids from tea infusions

In this study, a novel sorbent, 1-octyl-3-methylimidazolium hexafluorophosphate functionalised magnetic poly β-cyclodextrin, was successfully synthesised and applied to magnetic solid-phase extraction for the determination of pyrethroids in tea infusions. The sorbent was characterised by transmission electron microscopy, energy-dispersive spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, vibrating sample magnetometer and Brunauer-Emmett-Teller measurement. All factors affecting extraction efficiency, such as sorbent amount, extraction time, ionic strength and desorption conditions, were optimised individually. Under the chosen conditions, wide linearity (2.5-500 μg L^-1) with determination coefficients ranging from 0.9995 to 0.9999, low limits of detection of 0.32-0.54 μg L^-1 and good precision (intra-day: 2.6-7.0%; inter-day: 3.5-7.6%) were achieved for four pyrethroids in tea infusions. The relative recoveries of target analytes in real tea infusion samples were from 70% to 101% with relative standard deviations lower than 9.1%. We conclude that the proposed method is promising in the detection of pyrethroids in tea infusions.

Nasal biocompatible powder of Geraniol oil complexed with cyclodextrins for neurodegenerative diseases: physicochemical characterization and in vivo evidences of nose to brain delivery

Recently, many studies have shown that plant metabolites, such as geraniol (GER), may exert anti-inflammatory effects in neurodegenerative diseases and, in particular, Parkinson's disease (PD) models. Unfortunately, delivering GER to the CNS via nose-to-brain is not feasible due to its irritant effects on the mucosae. Therefore, in the present study β-cyclodextrin (βCD) and its hydrophilic derivative hydroxypropyl-beta-cyclodextrin (HPβCD) were selected as potential carriers for GER nose-to-brain delivery. Inclusion complexes were formulated and the biocompatibility with nasal mucosae and drug bioavailability into cerebrospinal fluid (CSF) were studied in rats. It has been demonstrated by DTA, FT-IR and NMR analyses that both the CDs were able to form 1:1 GER-CD complexes, arising long-term stable powders after the freeze-drying process. GER-HPβCD-5 and GER-βCD-2 complexes exhibited comparable results, except for morphology and solubility, as demonstrated by SEM analysis and phase solubility study, respectively. Even though both complexes were able to directly and safely deliver GER to CNS, GER-βCD-2 displayed higher ability in releasing GER in the CSF. In conclusion, βCD complexes can be considered a very promising tool in delivering GER into the CNS via nose-to-brain route, preventing GER release into the bloodstream and ensuring the integrity of the nasal mucosa.

Fluorescence-Based Sensing of Pesticides Using Supramolecular Chemistry

The detection of pesticides in real-world environments is a high priority for a broad range of applications, including in areas of public health, environmental remediation, and agricultural sustainability. While many methods for pesticide detection currently exist, the use of supramolecular fluorescence-based methods has significant practical advantages. Herein, we will review the use of fluorescence-based pesticide detection methods, with a particular focus on supramolecular chemistry-based methods. Illustrative examples that show how such methods have achieved success in real-world environments are also included, as are areas highlighted for future research and development.

Complexation of an Azo Dye by Cyclodextrins: A Potential Strategy for Water Purification

The chemistry of the host-guest complex formation has received much attention as a highly efficient approach for use to develop economical adsorbents for water purification. In the present study, the synthesis of three β-cyclodextrin (β-CD) inclusion complexes with the oil orange SS (OOSS) azo dye as a guest molecule and their potential applications in water purification are described. The complexes were synthesized by the coprecipitation method and characterized by Fourier transform infrared (FTIR) spectroscopy, UV-vis spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). FTIR and thermal analyses confirmed the encapsulation of OOSS dye within the hydrophobic cavity of β-CD. The encapsulation of hydrophobic dye inside the β-CD cavity was mainly due to the hydrophobic-hydrophobic interaction. The results showed that the stability of the OOSS dye had been improved after the complexation. The effect of three different compositions of the host-guest complexes was analyzed. The present study demonstrated that the hydrophobic dye could be removed from aqueous solution via inclusion complex formation. Thus, it can play a significant role in removing the highly toxic OOSS dye from the industrial effluent.

Inclusion complex of clausenidin with hydroxypropyl-β-cyclodextrin: Improved physicochemical properties and anti-colon cancer activity

The long-term objective of the present study was to prepare, physicochemically characterize and determine the anticancer of clausenidin/hydroxypropyl-β-cyclodextrin (Clu/HPβCD) inclusion complex. We used differential scanning calorimetry, X-ray diffractometer, fourier transform infrared spectroscopy, ultraviolet–visible spectrophotometer and ¹³C and ¹H nuclear magnetic resonance followed by in vitro anticancer assays. The orientation and intermolecular interactions of Clausenidin within cyclodextrin cavity were also ascertained by molecular docking simulation accomplished by AutoDock Vina. The guest molecule was welcomed by the hydrophobic cavity of the host molecule and sustained by hydrogen bond between host/guest molecules. The constant drug release with time, and increased solubility were found after successful complexation with HPβCD as confirmed by physicochemical characterizations. Clausenidin had greater cytotoxic effect on colon cancer HT29 cells when incorporated into HPβCD cavity than dissolved in DMSO. Also, from a comparison of cell viability between normal and cancer cells, a reduced side effect was observed. The Clu/HPβCD inclusion complex triggered reactive oxygen species-mediated cytotoxicity in HT29 cells. The inclusion complex-treated HT29 cells showed cell cycle arrest and death by apoptosis associated with caspases activation. The presence of HPβCD seems to aid the anticancer activity of clausenidin.

Exploring the Inclusion Complex of a Drug (Umbelliferone) with α-Cyclodextrin Optimized by Molecular Docking and Increasing Bioavailability with Minimizing the Doses in Human Body

In this study, umbelliferone and α-cyclodextrin host molecules have been mixed up through a coprecipitation method to prepare a supramolecular complex to provide physical insights into the formation and stability of the inclusion complex (IC). The prepared hybrid was characterized by ¹H nuclear magnetic resonance (¹H NMR), Fourier transform infrared (FTIR) spectroscopy, electrospray ionization (ESI) mass spectrometry, DSC, and fluorescence spectroscopic studies. Job's plot provides a stoichiometric ratio of 1:1 and the Benesi-Hildebrand double reciprocal plot gives binding constant values using fluorescence spectroscopic titrations and the ESI mass data support the experimental observations. The results of molecular modeling were systematically analyzed to validate the inclusion complexation. In preliminary computational screening, α-cyclodextrin IC of umbelliferone was found to be quite stable based on the docking score, binding free energies, and dynamic simulations. In addition, the results obtained from ¹H NMR and FTIR spectroscopy studies supported the inclusion complexation phenomenon. The results obtained from computational studies were found to be consistent with the experimental data to ascertain the encapsulation of umbelliferone into α-cyclodextrin.

Improvement of Pharmaceutical Properties of Zerumbone, a Multifunctional Compound, Using Cyclodextrin Derivatives

Zerumbone is a multifunctional compound which shows various biological activities, such as antitumor activity, anti-inflammatory activity, antiulcer activity, etc. However, to use Zerumbone as functional foods or medicines, its pharmaceutical properties such as solubility should be improved. In the present study, we prepared its inclusion complexes with various cyclodextrin (CyD) derivatives, and evaluated their solubility, release profile of the drug and cytotoxic activity. Among 11 CyDs, sulfobutylether (SBE)-β-CyD showed the highest solubilizing effect for Zerumbone. Phase solubility diagrams of SBE-β-CyD/Zerumbone in 10% methanol solution showed A_L type, and the stability constant was 756 M^-1. SBE-β-CyD also formed the solid complex with Zerumbone by kneading for 90 min. Importantly, the dissolution rate of Zerumbone was improved by complexation with SBE-β- and hydroxypropyl (HP)-β-CyDs, and its supersaturation was maintained for several hours. The solubilizing effects by SBE-β-CyD was greater than that of HP-β-CyD. Moreover, SBE-β-CyD/Zerumbone complex also retained the cytotoxic activity of Zerumbone. These results suggest that CyDs, especially SBE-β-CyD, were useful to improve the solubility of Zerumbone.

Insight into the Loading and Release Properties of MCM-48/Biopolymer Composites as Carriers for 5-Fluorouracil: Equilibrium Modeling and Pharmacokinetic Studies

The effect of the integration between MCM-48 and some biopolymers (starch, chitosan, and β-cyclodextrin) on enhancing the pharmaceutical properties of MCM-48 as advanced carriers for the 5-fluorouracil drug was studied considering the loading capacities and the release profiles. The prepared carriers are MCM-48/chitosan (MCM/CH), MCM-48/starch composite (MCM/ST), and MCM-48/β-Cyclodextrin (MCM/CD). They emphasized excellent 5-Fu loading capacities of 141.2 mg/g (MCM-48), 156.6 mg/g (MCM/ST), 191 mg/g (MCM/CH), and 170 mg/g (MCM/CD), reflecting significant enhancement in the loading capacities. The kinetic and equilibrium investigation suggested physisorption loading of 5-Fu drug in a monolayer form for MCM-48, MCM/ST, and MCM/CH (Langmuir) and in a multilayer form for MCM/CD (Freundlich). This was supported by the estimated adsorption energies (0.23 kJ/mol (MCM-48), 0.26 kJ/mol (MCM/ST), 0.3 kJ/mol (MCM/CH), and 0.75 kJ/mol (MCM/CD)) and the thermodynamic parameters of free energy and enthalpy. The obtained release profiles for 80 h reflected significant controlling for the releasing behavior of MCM/48 on integrating its structure by adjusting the type of the selected polymer and its ratio. The pharmacokinetic modeling and the diffusion exponent from the Korsmeyer-Peppas model suggested non-Fickian transport behavior (a combination of erosion and diffusion releasing mechanism) for MCM/ST, MCM/CH, and MCM/CD and Fickian diffusion behavior (diffusion releasing mechanism) for MCM-48.

Development of medicated chewing gum of taste masked levocetirizine dihydrochloride using different gum bases: in vitro and in vivo evaluation

Objective: The aim of this study was to develop medicated chewing gum (MCG) formulation for taste-masked levocetirizine dihydrochloride (LCZ) that can provide fast drug release into the salivary fluid.Methods: Taste-masked LCZ was first prepared by two methods: cyclodextrin complexation using Kleptose or Captisol and formation of drug resin complex using Kyron T-154 or Kyron T-314 to overcome poor LCZ palatability. MCGs were then prepared using the taste-masked drug, gum base (Artica-T, Chicle, or Health In Gum (HIG), plasticizer (glycerol or soy lecithin at 6 or 8% of the final gum weight). The developed MCGs were evaluated for physical properties, content uniformity, and drug release. Best release MCGs were evaluated thermally to investigate the plasticizer effectiveness and for ex vivo chew out study to confirm adequate drug release. Drug bioavailability was determined for selected formula compared to commercial tablets.Results: Based on taste-masking efficiency, drug/Kleptose complex (1:3 molar ratio) was chosen for incorporation into chewing gums. Physical properties and drug release showed that gum base type, plasticizer type, and level affected not only physical properties but also drug release from MCGs. Thermal study showed decreased glass transition temperature (Tg) with increased plasticizer level. Chew out study confirmed almost complete drug release after a few minutes of chewing. Pharmacokinetic results showed shorter t_max (0.585 vs. 1.375 h) and higher C_max (0.113 vs. 0.0765 μg/mL) for MCGs than conventional tablets.Conclusion: Results provided evidence that MCGs could be a better alternative to conventional tablet formulations with improved bioavailability and enhanced palatability.

Enhanced Solubility, Stability, and Herbicidal Activity of the Herbicide Diuron by Complex Formation with β-Cyclodextrin

The herbicide diuron is hardly soluble in water and most organic solvents and is usually made into a wettable powder or mixed with soil when used, which causes environmental risk and a reduction in herbicidal efficacy. In this study, the physicochemical properties were changed by using β-cyclodextrin (β-CD) to encapsulate diuron to form an inclusion complex. Some key technologies, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and nuclear magnetic resonance (1H NMR), were used to characterize the inclusion complex. The stoichiometry of the inclusion complex was determined by recording the 1H NMR spectrum or by using a diagram of inclusion ratios. A phase solubility study proved that the formed inclusion complex exhibited higher water solubility. Thermogravimetric analysis (TGA) demonstrated that the formed inclusion complex exhibited better thermal stability. Biological activity studies indicated that the herbicidal activity, in terms of herbicide removal, of the formed inclusion complex was higher than that of the original diuron. In general, the formation of the inclusion complex could reduce the environmental damage caused by diuron and enhance its herbicidal activity, providing an environmentally friendly method for using diuron.