Inclusion complex based on N-acetyl-L-cysteine and arginine modified hydroxypropyl-β-cyclodextrin for oral insulin delivery

Revealing mechanism of phenol-amine reaction to form humus in compost based on high-resolution liquid chromatography mass spectrometry and spectroscopy

Humus is the stable form of carbon storage in straw compost. The phenol-amine reaction is a pathway for humus formation in straw compost. In this study, two reaction systems, GP group (pyrogallol and glycine) and GCP group (catechol, pyrogallol, and glycine), were constructed in a simulated composting environment and revealed the molecular binding mechanism of the phenol-amine reaction through spectroscopy and mass spectrometry. The results showed that phenolic self-polymerization was faster than phenol-amine reaction. Therefore, the aromatization degree of GP was 27.14 % higher than that of GCP. The phenol-amine reaction first produced fulvic acid, and then formed humus units rich in active functional group structures (i.e., phenolic hydroxyl and carboxyl groups). These units further captured small molecule compounds to form humic acid eventually. This study would provide theoretical support for exploring the humus formation process and the promotion of straw humification by adding phenol or amino acids to compost.

Polymeric liposomes targeting dual transporters for highly efficient oral delivery of paclitaxel

A novel delivery system comprising N-succinic anhydride (N-SAA) and D-fructose co-conjugated chitosan (NSCF)-modified polymeric liposomes (NSCF-PLip) were designed to enhance oral delivery of paclitaxel (PTX) by targeting monocarboxylate transporters (MCT) and glucose transporters (GLUT). The synthesized NSCF was characterised by FT-IR and 1H NMR spectra. The prepared 30.78 % (degree of substitution of N-SAA) NSCF-PTX-PLip were approximately 150 nm in size, with a regular spherical shape, the zeta potential of -25.4 ± 5.13 mv, drug loading of 2.35 % ± 0.05 %, and pH-sensitive and slow-release characteristics. Compared with PTX-Lip, 30.78 % NSCF-PTX-PLip significantly enhanced Caco-2 cellular uptake via co-mediation of MCT and GLUT, showing relatively specific binding of propionic acid and MCT. Notably, the NSCF modification of PTX-Lip had no appreciable influence on their original cellular uptake pathway. The fructose modification of 30.78 % NSC-PTX-PLip significantly increased the concentration after tmax, indicating their continuous and efficient absorption. Compared with PTX-Lip, the 30.78 % NSCF-PTX-PLip resulted in a 2.09-fold extension of MRT, and a 6.06-fold increase of oral bioavailability. It significantly increased tumour drug distribution and tumour growth inhibition rate. These findings confirm that 30.78 % NSCF-PLip offer a potential oral delivery platform for PTX and targeting the dual transporters of MCT and GLUT is an effective strategy for enhancing the intestinal absorption of drugs.

Exploiting Apical Sodium-Dependent Bile Acid Transporter (ASBT)-Mediated Endocytosis with Multi-Functional Deoxycholic Acid Grafted Alginate Amide Nanoparticles as an Oral Insulin Delivery System

OBJECTIVE

Oral administration of insulin is a potential candidate for managing diabetes. However, it is obstructed by the gastrointestinal tract barriers resulting in negligible oral bioavailability.

METHODS

This investigation presents a novel nanocarrier platform designed to address these challenges. In this regard, the process involved amination of sodium alginate by ethylene diamine, followed by its conjugation with deoxycholic acid.

RESULTS

The resulting DCA@Alg@INS nanocarrier revealed a significantly high insulin loading content of 63.6 ± 1.03% and encapsulation efficiency of 87.6 ± 3.84%, with a particle size of 206 nm and zeta potentials of -3 mV. In vitro studies showed sustained and pH-dependent release profiles of insulin from nanoparticles. In vitro cellular studies, confocal laser scanning microscopy and flow cytometry analysis confirmed the successful attachment and internalization of DCA@Alg@INS nanoparticles in Caco-2 cells. Furthermore, the DCA@Alg@INS demonstrated a superior capacity for cellular uptake and permeability coefficient relative to the insulin solution, exhibiting sixfold and 4.94-fold enhancement, respectively. According to the uptake mechanism studies, the results indicated that DCA@Alg@INS was mostly transported through an energy-dependent active pathway since the uptake of DCA@Alg@INS by cells was significantly reduced in the presence of NaN3 by ~ 92% and at a low temperature of 4°C by ~ 94%.

CONCLUSIONS

Given the significance of administering insulin through oral route, deoxycholic acid-modified alginate nanoparticles present a viable option to surmount various obstacles presented by the gastrointestinal.

Cyclodextrins and derivatives in drug delivery: New developments, relevant clinical trials, and advanced products

Cyclodextrins (CD) and derivatives are functional excipients that can improve the bioavailability of numerous drugs. Because of their drug solubility improving properties they are used in many pharmaceutical products. Furthermore, the stability of small molecular drugs can be improved by the incorporation in CDs and an unpleasant taste and smell can be masked. In addition to well-established CD derivatives including hydroxypropyl-β-CD, hydroxypropyl-γ-CD, methylated- β-CD and sulfobutylated- β-CD, there are promising new derivatives in development. In particular, CD-based polyrotaxanes exhibiting cellular uptake enhancing properties, CD-polymer conjugates providing sustained drug release, enhanced cellular uptake, and mucoadhesive properties, and thiolated CDs showing mucoadhesive, in situ gelling, as well as permeation and cellular uptake enhancing properties will likely result in innovative new drug delivery systems. Relevant clinical trials showed various new applications of CDs such as the formation of CD-based nanoparticles, stabilizing properties for protein drugs or the development of ready-to-use injection systems. Advanced products are making use of various benefical properties of CDs at the same time. Within this review we provide an overview on these recent developments and take an outlook on how this class of excipients will further shape the landscape of drug delivery.

Polymeric nanoparticles (PNPs) for oral delivery of insulin

Successful oral insulin administration can considerably enhance the quality of life (QOL) of diabetes patients who must frequently take insulin injections. Oral insulin administration, on the other hand, is seriously hampered by gastrointestinal enzymes, wide pH range, mucus and mucosal layers, which limit insulin oral bioavailability to ≤ 2%. Therefore, a large number of technological solutions have been proposed to increase the oral bioavailability of insulin, in which polymeric nanoparticles (PNPs) are highly promising for oral insulin delivery. The recently published research articles chosen for this review are based on applications of PNPs with strong future potential in oral insulin delivery, and do not cover all related work. In this review, we will summarize the controlled release mechanisms of oral insulin delivery, latest oral insulin delivery applications of PNPs nanocarrier, challenges and prospect. This review will serve as a guide to the future investigators who wish to engineer and study PNPs as oral insulin delivery systems.

Material design for oral insulin delivery

Frequent insulin injections remain the primary method for controlling the blood glucose level of individuals with diabetes mellitus but are associated with low compliance. Accordingly, oral administration has been identified as a highly desirable alternative due to its non-invasive nature. However, the harsh gastrointestinal environment and physical intestinal barriers pose significant challenges to achieving optimal pharmacological bioavailability of insulin. As a result, researchers have developed a range of materials to improve the efficiency of oral insulin delivery over the past few decades. In this review, we summarize the latest advances in material design that aim to enhance insulin protection, permeability, and glucose-responsive release. We also explore the opportunities and challenges of using these materials for oral insulin delivery.

A nano-delivery system based on preventing degradation and promoting absorption to improve the oral bioavailability of insulin

Oral insulin delivery can improve patient compliance and simulate the portal-peripheral insulin concentration gradient produced by endogenous insulin, so oral insulin delivery has a broad prospect. However, some characteristics of the gastrointestinal tract, lead to low oral bioavailability. Therefore, a "ternary mutual-assist" nano-delivery system based on poly(lactide-co-glycolide) (PLGA) as the backbone combined with ionic liquids (IL) and vitamin B12-chitosan (VB12-CS) was constructed in this study, the protein protection performance of IL improves the room temperature stability of the loaded insulin during nanocarrier preparation, transportation and storage to a certain extent, and the protein protection function of IL combined with the slow degradation property of PLGA and the pH-responsive function of VB12-CS to prevent the degradation of insulin in the gastrointestinal tract. In addition, the mucosal adhesion function of VB12-CS, VB12 receptor- and clathrin-mediated transcellular transport involving VB12-CS and IL, and paracellular transport mediated by IL and CS can be combined to improve the intestinal epithelial transport efficiency of insulin, thus, the nanocarrier has stronger preventing degradation and promoting absorption effects. Pharmacodynamic studies showed that after oral administration of VB12-CS-PLGA@IL@INS NPs to diabetic mice, the blood glucose level decreased to about 13 mmol/L, below the critical point of 16.7 mmol/L, and the blood glucose reached a normal level, which was 0.4 times of the blood glucose value before administration, its relative pharmacological bioavailability was 31.8 %, higher than the general nanocarriers (10-20 %) and more beneficial to the clinical transformation of oral insulin.

Three generations of thiolated cyclodextrins: A direct comparison of their mucus permeating and mucoadhesive properties

AIM

This study aims to compare the mucus permeating and mucoadhesive properties of three generations of thiolated cyclodextrins (CDs).

METHODS

Free thiol groups of thiolated γ-CDs (CD-SH) were S-protected with 2-mercaptonicotinic acid (MNA), leading to a second generation of thiolated CDs (CD-SS-MNA) and with 2 kDa polyethylene glycol (PEG) bearing a terminal thiol group leading to a third generation of thiolated CDs (CD-SS-PEG). The structure of these thiolated CDs was confirmed and characterized by FT-IR, ¹H NMR and colorimetric assays. Thiolated CDs were evaluated regarding viscosity, mucus diffusion, and mucoadhesion.

RESULTS

The viscosity of the mixture of CD-SH, CD-SS-MNA, or CD-SS-PEG with mucus increased up to 11-, 16-, and 14.1-fold compared to unmodified CD within 3 hours, respectively. Mucus diffusion increased in the following rank order: unprotected CD-SH < CD-SS-MNA < CD-SS-PEG. The residence time of CD-SH, CD-SS-MNA, and CD-SS-PEG on porcine intestine was up to 9.6-, 12.55-, and 11.2-fold prolonged compared to native CD, respectively.

CONCLUSION

According to these results, S-protection of thiolated CDs can be a promising approach to improve their mucus permeating and mucoadhesive properties.

STATEMENT OF SIGNIFICANCE

Three generations of thiolated cyclodextrins (CDs) with different types of thiol ligands have been synthesized to improve mucus interaction. 1^st generation of thiolated CDs was synthesized by converting hydroxyl groups into thiols by reaction with Thiourea. For 2^nd generation, free thiol groups were S-protected by reaction with 2-mercaptonicotinic acid (MNA), resulting in high reactive disulfide bonds. For 3^rd generation, terminally thiolated short PEG chains (2 kDa) were used for S-protection of thiolated CDs. Mucus penetrating properties were found to be increased as follows: 1^st generation < 2^nd generation < 3^rd generation. Furthermore, mucoadhesive properties were improved in the following rank order: 1^st generation < 3^rd generation < 2^nd generation. This study suggests that the S-protection of thiolated CDs can enhance mucus penetrating and mucoadhesive properties.

A bifunctional hepatocyte-mitochondrion targeting nanosystem for effective astaxanthin delivery to the liver

A bifunctional hepatocyte-mitochondrion targeting nanosystem was prepared for astaxanthin by conjugating lactobionic acid (LA) and triphenylphosphonium-modified 2-hydroxypropyl-β-cyclodextrin onto sodium alginate. Hepatocyte-targeting evaluation indicated that the fluorescence intensity of HepaRG cells treated with the bifunctional nanosystem increased 90.3%, which was greater than that (38.7%) of the LA-only targeted nanosystem. The Rcoloc was 0.81 for the bifunctional nanosystem in mitochondrion-targeting analysis, which was greater than that (0.62) of the LA-only targeted nanosystem. The reactive oxygen species (ROS) level of the astaxanthin bifunctional nanosystem treated group significantly reduced to 62.20%, lower than that of free astaxanthin (84.01%) and LA-only targeted group (73.83%). Mitochondrial membrane potential recovered 97.35% in the astaxanthin bifunctional nanosystem treated group while the LA-only targeted group recovered 77.45%. The accumulation of bifunctional nanosystem in liver increased by 31.01% compared to the control. These findings indicated that the bifunctional nanosystem was beneficial for astaxanthin delivery in the liver precision nutrition intervention.

Hepatic-targeted delivery of astaxanthin for enhanced scavenging free radical scavenge and preventing mitochondrial depolarization

Astaxanthin (AST), as natural hydrophobic nutrition, has exhibited health-promoting benefits for its outstanding antioxidant property. However, most studies tend to enhance its stability and solubility while the targeted delivery of AST is limited. In this study, liver-targeted nanocarriers were designed and prepared by lactobionic acid-modified (2-hydroxypropyl-β-cyclodextrin) for efficient controlled delivery of AST. The minimum average size of AST nanoparticles was about 98 nm with a polydispersity index (PDI) of 0.41. The lactobionic acid-modified AST nanoparticles exhibited significant cellular uptake, and an admirable ability to scavenge free radicals for H₂O₂-induced HepaRG cells in preventing mitochondrial depolarization. Moreover, accumulation of AST nanoparticles in liver was observed due to the modification of lactobionic acid (LA) of the nanocarriers through the specific binding of LA-asialoglycoprotein receptors. The results in this study provided a new idea for liver-specific nutrition delivery of AST in developing functional food for liver disease nutrition intervention.

Thiolated cyclodextrins: A comparative study of their mucoadhesive properties

AIM

The aim of this study was the comparison of the mucoadhesive properties of nonionic, negatively, and positively charged thiolated cyclodextrins (CDs), including α-, β-, and γ-CDs of low and high degree of thiolation.

METHODS

Native α-, β-, and γ-CDs were thiolated with phosphorous pentasulfide in sulfolane (CD-SH) (i), via reductive amination with cysteamine after oxidative ring opening (CD-Cya) (ii), and via esterification with mercaptosuccinic acid (CD-MSA) (iii). These thiolated CDs were characterized via ¹H NMR and Ellman's test. Cytotoxicity was determined via resazurin and hemolysis assay. Mucoadhesive properties were evaluated via rheological studies with freshly isolated porcine mucus, as well as residence time studies on porcine small intestinal mucosa.

RESULTS

The structure of thiolated CDs was confirmed via ¹H NMR. The degree of thiolation was in the range of 594-1034 µmol/g for low and 1360-3379 µmol/g for high CD-SH, whereas thiolated CD-Cya and thiolated CD-MSA exhibited a degree of thiolation of 1142-3242 µmol/g and 243-1227 µmol/g, respectively. Just cationic CDs showed cytotoxicity. Nonionic highly thiolated α-CD-SH, α-CD-Cya, and α-CD-MSA exhibited with mucus 5.6-, 15.7- and 2.8-fold improved dynamic viscosity, while improvement was 7.7-, 6.1-, and 5.4-fold for the corresponding thiolated β-CDs and 12.3-, 15.4- and 17.8-fold for the corresponding thiolated γ-CDs compared with native CDs, respectively. A prolonged mucosal residence time following the rank order γ > β > α was observed for all thiolated CDs, whereby γ-CD-Cya, nonionic highly thiolated β-CD-SH and α-CD-Cya showed the highest mucoadhesive properties.

CONCLUSION

A high degree of thiolation and the introduction of cationic charges are mainly responsible for high mucoadhesive properties of CDs.

Cyclodextrins as eminent constituents in nanoarchitectonics for drug delivery systems

Cyclodextrins have been widely employed for drug delivery systems (DDSs) in which drugs are selectively delivered to a target site in the body. Recent interest has been focused on the construction of cyclodextrin-based nanoarchitectures that show sophisticated DDS functions. These nanoarchitectures are precisely fabricated based on three important features of cyclodextrins, namely (1) the preorganized three-dimensional molecular structure of nanometer size, (2) the easy chemical modification to introduce functional groups, and (3) the formation of dynamic inclusion complexes with various guests in water. With the use of photoirradiation, drugs are released from cyclodextrin-based nanoarchitectures at designated timing. Alternatively, therapeutic nucleic acids are stably protected in the nanoarchitectures and delivered to the target site. The efficient delivery of the CRISPR-Cas9 system for gene editing was also successful. Even more complicated nanoarchitectures can be designed for sophisticated DDSs. Cyclodextrin-based nanoarchitectures are highly promising for future applications in medicine, pharmaceutics, and other relevant fields.

Encapsulation of Benzyl Isothiocyanate with β-Cyclodextrin Using Ultrasonication: Preparation, Characterization, and Antibacterial Assay

Benzyl isothiocyanate (BITC) is widely utilized in multiple biomedical fields, due to its significant antibacterial properties and low toxicity. However, poor water solubility and pungent odor has limited its application in the food industry. In this study, we first prepared inclusion complexes of BITC in GLU-β-CD and HP-β-CD using ultrasound, which is able to overcome the hindrance of poor water solubility and high volatility. Then, the BITC-β-CD inclusion complexes were characterized by using high-performance liquid chromatography (HPLC), nuclear magnetic resonance hydrogen spectra (¹H-NMR), infrared absorption spectra (IR), and differential scanning calorimetry (DSC) to confirm their stability. Further, the evaluation of antibacterial and antitumor effects of the BITC-β-CD inclusion complexes showed that they had great bactericidal activity against both Escherichia coli and Staphylococcus aureus cells, and also inhibited the growth of HepG2 cells in vitro. In addition, our results indicated that BITC-β-CD complexes were able to inhibit the growth of S. aureus in broccoli juice and extend the shelf life of broccoli juice, demonstrating the potential of β-cyclodextrin to improve the stability and controlled release of BITC. Taken together, our results show that BITC-β-CD complexes have good potential for application in the food industry.

Design Strategy for Vulcanization Accelerator of Diphenylguanidine/Cyclodextrin Inclusion Complex for Natural Rubber Latex Foam with Enhancing Performance

Vulcanization is an essential process to obtain high-performance rubber products. Diphenylguanidine (DPG) is often used as the secondary accelerator in the vulcanization process of natural rubber (NR) latex. However, DPG would make NR latex emulsion exhibit gelation, resulting in the negative vulcanization efficiency. In addition, exposure to DPG might lead to some physiological diseases during the production process of DPG doped NR latex. Hydroxypropyl-β-cyclodextrin (HP-β-CD) with the hydrophobic interior and hydrophilic exterior has the advantages of good water solubility, high bioavailability, reliable stability, and low toxicity. In this study, the inclusion complex of diphenylguanidine-hydroxypropyl-β-cyclodextrin (DPG-HP-β-CD) is prepared by ball milling with a host-guest molar ratio of 1 : 1, which has also been applied to the foaming process of NR latex. The mechanical properties of DPG-HP-β-CD inclusion complex/natural rubber latex foam (DPG-HP-β-CD/NRLF) have been significantly improved, including the tensile strength, elongation at break, hardness, compression set, resilience, and antiaging performance. Further, the usage of DPG has been reduced, leading to the reduction of toxicity and environmental hazards.

Emerging technologies to increase gastrointestinal transit times of drug delivery systems

Apart from already established technologies to increase gastrointestinal transit times, including devices rapidly increasing in size once they have reached the stomach in order to retard the passage through the pylorus, formulations that float on gastric fluids and mucoadhesive drug delivery systems adhering to the gastrointestinal mucosa, there are new technologies emerging that might be game changing. They include mucus permeating nanocarriers that are able to diffuse deeply into the mucus gel layer of the gastric and intestinal mucosa remaining there for a prolonged time period (i), charge-converting nanocarriers that shift their zeta potential from negative to positive within the mucus gel layer providing strong ionic bonds with anionic mucus glycoproteins (ii) and thiolated nanocarriers and cyclodextrins form even covalent bonds with cysteine-rich subdomains of mucus glycoproteins (iii). Within this review we will provide an overview about these emerging new technologies and will critically discuss their potential and shortcomings.

Hyaluronic Acid Coated Chitosan Nanoparticles for Insulin Oral Delivery: Fabrication, Characterization and Hypoglycemic Ability

Oral administration of insulin faces multiple biological challenges, such as varied digestive environments, mucin exclusion and low epithelial cells absorption. In the present study, a hyaluronic acid coated chitosan nanoparticle delivery system was fabricated for insulin oral delivery. It is hypothesized that the developed nanoparticles will protect insulin from digestive degradation, promote intestinal epithelial cell absorption and exert strong in vivo hyperglycemic ability. Nanoparticles formulated by chitosan (CS) and sodium tripolyphosphate (TPP) was optimized to form the core nanoparticles (CNP). Hyaluronic acid (HA) was further applied to coat CNP (HCP) to improve stability, reduce enzymatic degradation and promote absorption of insulin. HCP promoted insulin uptake by Caco-2 cells, absorbed less mucin and improved intestinal absorption. Moreover, in vivo test demonstrated that oral administration of insulin-loaded HCP exerts strong and continuous hyperthermia effect (with PA of 13.8%). In summary, HCP is a promising delivery platform for insulin oral administration in terms of protecting insulin during digestion, facilitating its absorption and ultimately promoting its oral bioavailability. This article is protected by copyright. All rights reserved.

Impact of calcium ions and degree of oxidation on the structural, physicochemical, and in-vitro release properties of resveratrol-loaded oxidized gellan gum hydrogel beads

Oxidized gellan gum (OGG) hydrogel beads as delivery systems for resveratrol were fabricated by ionic cross-linking with calcium chloride (CaCl₂). The degree of oxidation (DO) and CaCl₂ concentration had significant influences on the formation and functional properties of hydrogel beads. The resveratrol encapsulation efficiency (66.43%-79.84%) and loading capacity (4.15%-5.05%) of OGG hydrogel beads were enhanced as DO increased. The hydrogel beads exhibited a uniform spherical shape as observed by scanning electron microscope. Fourier transform infrared spectroscopy analysis confirmed that hydrogen bonds and ionic interaction participated in the formation of hydrogel beads. X-ray diffraction analysis revealed that the physical state of resveratrol was changed from crystalline to amorphous form after encapsulation. Furthermore, the physical stability and antioxidant capacity evaluation demonstrated that the hydrogel bead fabricated with DO80 OGG and CaCl₂ concentration of 1.0 M could provide high protection for resveratrol against degradation by environmental stresses and maintain its antioxidant capacity. The DO and CaCl₂ concentrations could modulate the in-vitro release behaviors of hydrogel beads and obtain a good small intestinal-targeted release of resveratrol at high DO and medium CaCl₂ concentration. These findings suggested that a promising delivery system for encapsulating bioactive ingredients can be fabricated by rational design.

Efficacy and safety of 28-day treatment with oral insulin (ORMD-0801) in patients with type 2 diabetes: A randomized, placebo-controlled trial

AIM

To assess the safety and efficacy of oral insulin (ORMD-0801) in patients with type 2 diabetes (T2D).

MATERIALS AND METHODS

After a 2-week washout of other medications, adult metformin-treated patients with T2D were randomized to receive placebo or 16 or 24 mg ORMD-0801, once daily, at bedtime, for 28 days. The mean change from baseline weighted mean night-time glucose levels was determined from 2 nights of continuous glucose monitoring (CGM) recordings during the placebo run-in and last week of treatment.

RESULTS

In total, 188 patients (HbA1c: 7.82% ± 0.88% [placebo] and 8.08% ± 1.11% [pooled ORMD-0801 group]) were enrolled. In the placebo group, mean night-time CGM increased from baseline by 13.7 ± 26.1 mg/dL, whereas the increase was significantly smaller in the pooled ORMD-0801 group (1.7 ± 23.5 mg/dL, P = .0120). Glycaemic control variables (24-hour, fasting and daytime CGM glucose) also displayed smaller increases with ORMD-0801 versus placebo. Change from baseline HbA1c was -0.01% in the pooled ORMD-0801 group versus +0.20% in the placebo group (P = .0149). ORMD-0801 was well tolerated, with similar adverse event and hypoglycaemia rates as placebo.

CONCLUSIONS

In patients with T2D, bedtime ORMD-0801 curbed increases in night-time glycaemia, 24-hour glycaemia and HbA1c, without increasing the risk of hypoglycaemia or safety events compared with the control arm.

New potential application of hydroxypropyl-β-cyclodextrin in solid self-nanoemulsifying drug delivery system and solid dispersion

The purpose of this study was to use hydroxypropyl-β-cyclodextrin (HP-β-CD) as a novel carrier in solid SNEDDS and solid dispersions to enhance the solubility and oral bioavailability of poorly water-soluble dexibuprofen. The novel dexibuprofen-loaded solid SNEDDS was composed of dexibuprofen, corn oil, polysorbate 80, Cremophor® EL, and HP-β-CD at a weight ratio of 45/35/50/15/100. This solid SNEDDS spontaneously formed a nano-emulsion with a size of approximately 120 nm. Unlike the conventional solid SNEDDS prepared with colloidal silica as a carrier, this dexibuprofen-loaded solid SNEDDS exhibited a spherical structure. Similar to the dexibuprofen-loaded solid dispersion prepared with HP-β-CD, the transformation of the crystalline drug to an amorphous state with no molecular interactions were observed in the solid SNEDDS. Compared to the solid dispersion and dexibuprofen powder, solid SNEDDS significantly enhanced drug solubility and AUC. Therefore, HP-β-CD is a novel potential carrier in SNEDDS for improving the oral bioavailability of dexibuprofen.

β-Cyclodextrin-Polyacrylamide Hydrogel for Removal of Organic Micropollutants from Water

Water pollution by various toxic substances remains a serious environmental problem, especially the occurrence of organic micropollutants including endocrine disruptors, pharmaceutical pollutants and naphthol pollutants. Adsorption process has been an effective method for pollutant removal in wastewater treatment. However, the thermal regeneration process for the most widely used activated carbon is costly and energy-consuming. Therefore, there has been an increasing need to develop alternative low-cost and effective adsorption materials for pollutant removal. Herein, β-cyclodextrin (β-CD), a cheap and versatile material, was modified with methacrylate groups by reacting with methacryloyl chloride, giving an average degree of substitution of 3 per β-CD molecule. β-CD-methacrylate, which could function as a crosslinker, was then copolymerized with acrylamide monomer via free-radical copolymerization to form β-CD-polyacrylamide (β-CD-PAAm) hydrogel. Interestingly, in the structure of the β-CD-PAAm hydrogel, β-CD is not only a functional unit binding pollutant molecules through inclusion complexation, but also a structural unit crosslinking PAAm leading to the formation of the hydrogel 3D networks. Morphological studies showed that β-CD-PAAm gel had larger pore size than the control PAAm gel, which was synthesized using conventional crosslinker instead of β-CD-methacrylate. This was consistent with the higher swelling ratio of β-CD-PAAm gel than that of PAAm gel (29.4 vs. 12.7). In the kinetic adsorption studies, phenolphthalein, a model dye, and bisphenol A, propranolol hydrochloride, and 2-naphthol were used as model pollutants from different classes. The adsorption data for β-CD-PAAm gel fitted well into the pseudo-second-order model. In addition, the thermodynamic studies revealed that β-CD-PAAm gel was able to effectively adsorb the different dye and pollutants at various concentrations, while the control PAAm gel had very low adsorption, confirming that the pollutant removal was due to the inclusion complexation between β-CD units and pollutant molecules. The adsorption isotherms of the different dye and pollutants by the β-CD-PAAm gel fitted well into the Langmuir model. Furthermore, the β-CD-PAAm gel could be easily recycled by soaking in methanol and reused without compromising its performance for five consecutive adsorption/desorption cycles. Therefore, the β-CD-PAAm gel, which combines the advantage of an easy-to-handle hydrogel platform and the effectiveness of adsorption by β-CD units, could be a promising pollutant removal system for wastewater treatment applications.