Lidocaine/β-cyclodextrin inclusion complex as drug delivery system

Sustained release local anesthetics for pain management: relevance and formulation approaches

This review attempted to ascertain the rationale for the formulation of sustained-release local anesthetics and summarize the various formulation approaches designed to date to achieve sustained and localized local analgesic effects. The incidence of pain, which is the concern of patients as well as health care professionals, is increasing due to accidents, surgical procedures, and other diseases. Local anesthetics can be used for the management of moderate to severe acute and chronic pain. They also allow regional analgesia, in situations where the cause and source of the pain are limited to a particular site or region, without the need for loss of consciousness or systemic administration of other analgesics thereby decreasing the risk of potential toxicities. Though they have an interesting antipain efficacy, the short duration of action of local anesthetics makes the need for their multiple injections or opioid adjuvants mandatory. To overcome this problem, different formulations are being designed that help achieve prolonged analgesia with a single dose of administration. Combination with adjuvants, liposomal formulations, lipid-based nanoparticles, thermo-responsive nanogels, microspheres, microcapsules, complexation with multivalent counterions and HP-β-CD, lipid-based nanoparticles, and bio-adhesive films, and polymeric matrices are among the approaches. Further safety studies are required to ensure the safe and effective utilization of sustained-release local anesthetics. Moreover, the release kinetics of the various formulations should be adequately established.

Lidocaine-Liposomes-A Promising Frontier for Transdermal Pain Management

(1) Background: We aim to develop novel gel formulations for transdermal drug delivery systems in acute and inflammatory pain therapy. (2) Methods: We induced inflammation by the injection of λ-carrageenan on the hind paw of 80 Wistar male rats. The animals were randomized into eight groups of 10 rats each: C (placebo gel), E (EMLATM), L (lidocaine 2%), L-CD (lidocaine + cyclodextrin 2.5%), L-LP (lidocaine + liposomes 1.7%), L-CS (lidocaine + chitosan 4%), L-CSh (lidocaine + chitosan hydrochloride), and L-CS-LP (lidocaine + chitosan + liposomes). The behavior response was determined with a hot plate, cold plate, and algesimeter, each being performed at 30, 60, 120, 180, and 240 min after pain induction. At the end of the experiment, tissue samples were collected for histological assessment. (3) Results: L-LP had the greatest anesthetic effects, which was proven on the cold plate test compared to placebo and EMLATM (all p ≤ 0.001). L-CS-LP had a significant effect on cold plate evaluation compared to placebo (p ≤ 0.001) and on hot plate evaluation compared to EMLATM (p = 0.018). (4) Conclusions: L-LP is a new substance with a substantial analgesic effect demonstrated by the cold plate in the first 120 min. Further studies with more animals are needed to determine the maximum doses that can be applied for a better analgesia with minimum side effects.

Regulation of Released Alkali from Gel Polymer Electrolyte in Quasi-Solid State Zn-Air Battery

Gel polymer electrolyte (GPE) in quasi-solid state Zn-air battery (QSZAB) will release alkali during cycling, resulting in gradual dehydration of GPE, corrosion of Zn electrode, Zn dendrites growth, and therefore inferior performance. Here, hollow Sn microspheres are prepared on Zn substrate by the technique of colloidal self-assembly. The inner surfaces of hollow Sn microspheres are modified by 2-hydroxypropyl-β-cyclodextrin (hollow Sn-inner HPβCD) to regulate the released alkali at GPE|anode interface. The hollow Sn-inner HPβCD can lessen the leakage of released alkali, make stored alkali diffuse back to GPE during the charging process, and mitigate the loss of soluble Zn(OH)₄ ^2- to suppress Zn dendrites growth. Resultantly, GPE in QSZAB with hollow Sn-inner HPβCD exhibits a high retention capacity for alkaline solution. The cell also exhibits a long cyclic lifespan of 127 h due to the effective regulation of released alkali, which outperforms QSZAB without hollow Sn-inner HPβCD by 7.94 times. This work rivets the regulation of released alkali at GPE|anode interface, providing new insight to improve QSZABs' performance.

Interactions of Sodium Salicylate with β-Cyclodextrin and an Anionic Resorcin[4]arene: Mutual Diffusion Coefficients and Computational Study

The interaction between sodium salicylate (NaSal) and the two macrocycles 5,11,17,23-tetrakissulfonatomethylene-2,8,14,20-tetra(ethyl)resorcinarene (Na₄EtRA) and β-cyclodextrin (β-CD) has been studied by the determination of ternary mutual diffusion coefficients, and spectroscopic and computational techniques. The results obtained by the Job method suggest that the complex formation is given in a 1:1 ratio for all systems. The mutual diffusion coefficients and the computational experiments have shown that the β-CD-NaSal system presents an inclusion process, whereas the Na₄EtRA-NaSal system forms an outer-side complex. This fact is also in line with the results obtained from the computational experiments, where the calculated solvation free energy has been found to be more negative for the Na₄EtRA-NaSal complex because of the partial entry of the drug inside the Na₄EtRA cavity.

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.

New chromatographic insights on drug:cyclodextrin inclusion complexes and their potential use in drug delivery

OBJECTIVES

Cyclodextrins (CDs) play a pivotal role in the controlled release of drugs; however, their ability to gradually release drugs is here interrogated: can cyclodextrins, even those that form strong inclusion complexes, sustain a prolonged release of drugs?

METHODS

An original chromatographic approach was developed and accordingly we classified and determined drugs that form the most stable inclusion complexes with cyclodextrins. β-CD and hydroxypropyl-β-CD (HP-β-CD) were coupled to pullulan (Pul) microspheres and packed into a chromatographic column. Then, different drugs or model compounds were eluted, and values of the retention time (RT) were determined. In vitro release studies were performed for drugs that form the most stable inclusion complexes.

RESULTS

The drugs with the longest RT value form the most stable inclusion complexes with Pul/β-CD and Pul/HP-β-CD microspheres. Pul/β-CD microspheres form more stable inclusion complexes than Pul/HP-β-CD microspheres. However, in spite of their high stability, they were not able to gradually release the included drug (15 min release time). The cross-chromatographic experiments confirmed the hypothesis that in aqueous solution, drug/cyclodextrin complexes are continuously associated and dissociated.

CONCLUSIONS

If the dissociation of the guest molecule is very rapid, why is it expected that these complexes gradually release the drug?

Nano Modification of Antrodia Cinnamomea Exhibits Anti-Inflammatory Action and Improves the Migratory Potential of Myogenic Progenitors

The skeletal muscle progenitors’ proliferation and migration are crucial stages of myogenesis. Identifying drug candidates that contribute to myogenesis can have a positive impact on atrophying muscle. The purpose of the study is to synthesize the Antrodia cinnamomea (AC)-β-cyclodextrin (BCD) inclusion complex (IC) and understand its in vitro pro-regenerative influence in murine skeletal C2C12 myoblasts. The IC was subjected to various nano-characterization studies. Fluorescent IC was synthesized to understand the cellular uptake of IC. Furthermore, 25 µg/mL, 12.5 µg/mL, and 6.25 µg/mL of IC were tested on murine C2C12 skeletal muscle cells for their anti-inflammatory, pro-migratory, and pro-proliferative action. The cellular internalization of IC occurred rapidly via pinocytosis. IC (252.6 ± 3.2 nm size and −37.24 ± 1.55 surface charge) exhibited anti-inflammatory action by suppressing the secretion of interleukin-6 and enhanced cell proliferation with promising cytocompatibility. A 12.5 μg/mL dose of IC promoted cell migration in 24 h, but the same dose of AC significantly reduced cell migration, suggesting modification by BCD. Molecular studies revealed that IC promoted C2C12 myoblasts migration by upregulating long non-coding RNA (lncRNA) NEAT-1, SYISL, and activating the pPKC/β-catenin pathway. Our study is the first report on the pro-proliferative and pro-migratory effects of BCD-modified extracts of AC.

API-polymer interactions in Sepineo P600 based topical gel formulation- impact on rheology

In the present study, topical gel and emulsion gel were formulated using Acrylamide/ Sodium Acryloyldimethyl taurate copolymer (Sepineo P600) as a gelling agent, and their rheological attributes and physical stability were evaluated upon incorporation of API. Lidocaine, a free base drug (pK_a 7.92) was used as a model drug in all formulations. Medium- chain Triglycerides (MCT) was used as a dispersed phase to prepare the emulgel. Results show that the rheological properties of both gel and emulgel such as viscosity, elastic moduli and yield stress were significantly influenced by the pH of the topical formulations and API concentration. A lower pH (pH < pKa) leads to the increase in number of cationic species of lidocaine, which results in the weakening of the structure of the gel matrix by charge screening of polymer-polymer repulsions. Interactions between API and polymer chains through electrostatic attraction may play a major role in altering the rheology, which could potentially impact the physical stability against phase separation of the internal phase in emulsion gel samples. This study provides valuable insights into rheological behaviors of Sepineo P600 gel and emulgel which can be modified or tuned though the interplay of the API properties and critical formulation parameters such as pH. The tunable rheological properties with simpler manufacturing process make Sepineo P600 gel and emulsion gel very suitable systems for use in semisolid topical formulations.

In vitro and in vivo evaluation of a novel lidocaine-loaded cubosomal gel for prolonged local anesthesia

Marketed lidocaine dosage forms (such as ointment, gels, and injections) used to manage acute and chronic pain showed a short duration of action (<2 h). In this study, a lidocaine-loaded cubosomal gel was prepared to sustain the release of lidocaine to prolong the local anesthetic effect (high drug retention in the skin). Lidocaine-loaded cubosomal gels were prepared by melt emulsification and sonication using Pluronic F127 and DL-α-monoolein (at different levels). The cubosomal gels were characterized by morphology, size, zeta potential, entrapment efficacy, assay, viscosity, pH, and texture profiles. Ex vivo lidocaine permeation and retention studies were performed using Sprague–Dawley rat skin. Transmission electron microscopy images confirmed the bi-continuous liquid crystalline phase with a honeycomb cubosome structure. The cubosomal particle size (103–227 nm), viscosity (13,524–15,627cp), and entrapment efficacy (78.4–94.7%) increase with the level of monoolein. The ex-vivo permeation study showed a biphasic release pattern, with lidocaine cleared from ointment within 4 h (97.9% cumulative release), while cubosomal gels showed sustained release up to 24 h (53.33–98.86% cumulative release). A skin retention study demonstrated that cubosomes can increase (up to 28-fold) the lidocaine content in the skin (4.56 mg) compared to ointment (0.19 mg). A rabbit skin irritation study showed no sign of irritation after the application of cubosomal gel. In the radiant heat tail-flick study, the local anesthetic effect of lidocaine from the cubosomal gel was sustained for up to 16 h with 1.43-fold higher efficacy than marketed ointment. In conclusion, the study demonstrated the potential of cubosomal nanoparticle-laden gel to sustain the release of lidocaine for prolonging local anesthetic effects for pain management.

Lidocaine-Loaded Hyaluronic Acid Adhesive Microneedle Patch for Oral Mucosal Topical Anesthesia

The pain and fear caused by direct local injection of anesthetic or the poor experience with surface anesthetic cream increase the difficulty of clinical treatment for oral diseases. To address this problem, a hyaluronic acid microneedle patch (Li-HAMNs) that consists of fast-dissolving lidocaine hydrochloride (LDC)-loaded tips and a wet-adhesive backing layer made of polyvinyl alcohol (PVA)/carboxymethylcellulose sodium (CMC-Na) was fabricated to explore its potential use in dental topical anesthesia. Li-HAMNs could puncture the stratum corneum with an insertion depth of about 279 μm in the isolated porcine oral mucosal. The fast-dissolving tips could release LDC to improve the patients’ convenience and compliance. Importantly, the backing layer, which has good adhesion ability and water-absorbing properties, could surmount the contraction and extension of oral masticatory muscles and the saliva scour. In the tail flick test, the topical anesthesia efficacy of the Li-HAMNs group was much better than clinical lidocaine cream (EMLA cream, LDC, 1.2 mg) in spite of a relatively lower LDC dose with Li-HAMNs (LDC, 0.5 mg). It is believed that the proposed adhesive microneedle patch could enhance transmucosal delivery of anesthetics and thus open a new chapter in the painless treatment of oral diseases.

Poly(N-vinyl imidazole) Cross-Linked β-Cyclodextrin Hydrogel for Rapid Hemostasis in Severe Renal Arterial Hemorrhagic Model

A unique facile process has been adopted for fast assembly of a poly(N-vinyl imidazole) cross-linked β-cyclodextrin hydrogel through microwave-assisted free radical polymerization, using N,N'-methylenebis(acrylamide) cross-linker. The copolymer possesses positive surface charge, one of the characteristic properties of an ideal hemostatic hydrogel. The functionalized imidazole-based hydrogel demonstrates rapid, superior blood coagulation kinetics under in vitro and in vivo conditions. On application to a major renal arterial hemorrhagic model, this hydrogel shows better blood clotting kinetics, leading to complete hemostasis in as few as ∼144 ± 7 s. Additionally, 350 μL of whole blood was clotted instantly, in ∼35 s, and therefore, reinforcing its hemostatic potential. The hydrogel demonstrates excellent biocompatibility, when seeded with human dermal fibroblast cells, retaining the native property of its predecessor. In addition, the hydrogel presents excellent hemocompatibility when tested with whole blood with the highest hemolytic ratio of 1.07 ± 0.05%. Moreover, it also demonstrates potential as a carrier for sustained release of an anesthetic drug, lidocaine hydrochloride monohydrate (∼83% in 24 h). The rapid hemostatic behavior of the hydrogel is coupled with its cytocompatibility and hemocompatibilty properties along with controlled drug release characteristics. These behaviors evidently demonstrate it to be an excellent alternative for a superior hemostatic material for severe hemorrhagic conditions.

Preliminary Study for the Preparation of Transmucosal or Transdermal Patches with Acyclovir and Lidocaine

The present study aimed to prepare and evaluate patches for the controlled release of lidocaine/acyclovir and the binary mixture between lidocaine: acyclovir in the oral cavity. Mucoside adhesive patches containing 12.5 mg/cm² lidocaine/acyclovir or binary mixture base were developed by a solvent casting method using sodium alginate, polyvinylpyrrolidone (PVP), glycerol (Gly), polyvinyl alcohol (PVA), and Span 80 (S). Binary mixtures between all components were prepared before the patches' formulation in order to be able to check the substance compatibility. All formulated patches were analyzed by FT-IR spectroscopy, UV-Vis analysis, thermogravimetry (TGA), and scanning electron microscopy (SEM). FT-IR and TGA analyses were also used to check compatibility between binary mixtures. The study establishes which membranes are indicated in the controlled release of lidocaine/acyclovir and those membranes that contain both active principles. Membranes based on alginate, PVP, and PVA can be used to release the active substance. Simultaneously, membranes with SPAN used as a gelling agent were excluded due to the interaction with the active substance. The following membranes composition have been chosen for lidocaine release: Alginate:Gly and Alginate:Gly:PVP. At the same time, the following membrane compositions were chosen for acyclovir membranes: Alginate:Gly:PVP and Alginate:PVA:Gly. Both active substances could be included to obtain a homogeneous distribution only in the membrane based on alginate, PVA, and Gly.

Development and optimization of tibezonium iodide and lignocaine hydrochloride containing novel mucoadhesive buccal tablets: A pharmacokinetic investigation among healthy humans

OBJECTIVE

It is clinically important to deliver sustained-release mucoadhesive dosage of local anesthetic and antimicrobial agent for pain control. The current study aimed to develop and evaluate chitosan (CHI) based buccal mucoadhesive delivery for local release of tibezonium iodide (TBN) and lignocaine hydrochloride (LGN).

METHODS

Direct compression technique was employed, aided by other mucoadhesive polymers like hydroxypropylmethylcellulose (HPMC) and sodium alginate (SA) and evaluated for physicochemical and in vivo character.

RESULTS

Fourier transform infrared spectral analysis (FTIR), powdered X-ray diffraction (XRPD), and differential scanning calorimetry (DSC) absence of physical interaction between ingredients. The physical parameters complied with USP specifications for all formulations. Optimum swellability (551.9%) was offered from formulation TL15, containing 30% SA. Highest ex vivo mucoadhesive strength (24.79 g) and time (18.39 h) was found with TL8. Formulation TL8 also exhibited maximum in vivo residence time (11.37 h). Almost complete drug release at 6 h was possessed by formulation TL5 (HPMC and CHI, 20% each) for TBN (99.98%) and LGN (99.06%). The optimized formulation TL5 exhibited dosage stability up to 6 months at 75% relative humidity and retained drug contents. TL5 was well tolerated by the volunteers with no inflammation, pain or irritation found. Almost 73% of volunteers reported an increase in salivary secretion. The first-order salivary C_max of TBN and LGN were found as 16.02 and 7.80 µg/mL within 4 h, respectively.

CONCLUSION

Therefore, the sustained release mucoadhesive dosage form of TBN and LGN can be an effective and alternative option to conventional delivery.

On the Interactions of Melatonin/β-Cyclodextrin Inclusion Complex: A Novel Approach Combining Efficient Semiempirical Extended Tight-Binding (xTB) Results with Ab Initio Methods

Melatonin (MT) is a molecule of paramount importance in all living organisms, due to its presence in many biological activities, such as circadian (sleep-wake cycle) and seasonal rhythms (reproduction, fattening, molting, etc.). Unfortunately, it suffers from poor solubility and, to be used as a drug, an appropriate transport vehicle has to be developed, in order to optimize its release in the human tissues. As a possible drug-delivery system, β-cyclodextrin (βCD) represents a promising scaffold which can encapsulate the melatonin, releasing when needed. In this work, we present a computational study supported by experimental IR spectra on inclusion MT/βCD complexes. The aim is to provide a robust, accurate and, at the same time, low-cost methodology to investigate these inclusion complexes both with static and dynamic simulations, in order to study the main actors that drive the interactions of melatonin with β-cyclodextrin and, therefore, to understand its release mechanism.

Indwelling urinary catheter assembled with lidocaine-loaded polymeric strand for local sustained alleviation of bladder discomfort

Indwelling urinary catheters (IUCs) are used in clinical settings to assist detrusor contraction in hospitalized patients. However, an inserted IUC often causes catheter-related bladder discomfort. To resolve this, we propose an IUC coupled with local, sustained release of an anesthetic drug, lidocaine. For this, a thin strand composed of poly (lactic-co-glycolic acid) and lidocaine was separately prepared as a drug delivery carrier, which was then wound around the surface of the IUC to produce the drug-delivery IUC. Our results revealed that the drug-delivery IUC could exert the pain-relief effects for up to 7 days when placed in the bladder of living rats. Cystometrogram tests indicated that the drug-delivery IUC could significantly relieve bladder discomfort compared with the IUC without lidocaine. Furthermore, the expression of pain-related inflammatory markers, such as nerve growth factor, cyclooxygenase-2, and interleukin-6 in the biopsied bladder tissues was significantly lower when the drug-delivery IUC was used. Therefore, we conclude that an IUC simply assembled with a drug-loaded polymer strand can continuously release lidocaine to allow for the relief of bladder discomfort during the period of IUC insertion.

Research Progress on Synthesis and Application of Cyclodextrin Polymers

Cyclodextrins (CDs) are a series of cyclic oligosaccharides formed by amylose under the action of CD glucosyltransferase that is produced by Bacillus. After being modified by polymerization, substitution and grafting, high molecular weight cyclodextrin polymers (pCDs) containing multiple CD units can be obtained. pCDs retain the internal hydrophobic-external hydrophilic cavity structure characteristic of CDs, while also possessing the stability of polymer. They are a class of functional polymer materials with strong development potential and have been applied in many fields. This review introduces the research progress of pCDs, including the synthesis of pCDs and their applications in analytical separation science, materials science, and biomedicine.

Functionalization of Gold Nanostars with Cationic β-Cyclodextrin-Based Polymer for Drug Co-Loading and SERS Monitoring

Gold nanostars (AuNSs) exhibit modulated plasmon resonance and have a high SERS enhancement factor. However, their low colloidal stability limits their biomedical application as a nanomaterial. Cationic β-cyclodextrin-based polymer (CCD/P) has low cytotoxicity, can load and transport drugs more efficiently than the corresponding monomeric form, and has an appropriate cationic group to stabilize gold nanoparticles. In this work, we functionalized AuNSs with CCD/P to load phenylethylamine (PhEA) and piperine (PIP) and evaluated SERS-based applications of the products. PhEA and PIP were included in the polymer and used to functionalize AuNSs, forming a new AuNS-CCD/P-PhEA-PIP nanosystem. The system was characterized by UV–VIS, IR, and NMR spectroscopy, TGA, SPR, DLS, zeta potential analysis, FE-SEM, and TEM. Additionally, Raman optical activity, SERS analysis and complementary theoretical studies were used for characterization. Minor adjustments increased the colloidal stability of AuNSs. The loading capacity of the CCD/P with PhEA-PIP was 95 ± 7%. The physicochemical parameters of the AuNS-CCD/P-PhEA-PIP system, such as size and Z potential, are suitable for potential biomedical applications Raman and SERS studies were used to monitor PhEA and PIP loading and their preferential orientation upon interaction with the surface of AuNSs. This unique nanomaterial could be used for simultaneous drug loading and SERS-based detection.

Lidocaine-loaded reduced graphene oxide hydrogel for prolongation of effects of local anesthesia: In vitro and in vivo analyses

Lidocaine is widely used as a local anesthetic for alleviation of post-operative pain and for management of acute and chronic painful conditions. Although several approaches are currently used to prolong the duration of action, an effective strategy to achieve neural blockage for several hours remains to be identified. In this study, a lidocaine-loaded Pluronic® F68-reduced graphene oxide hydrogel was developed to achieve sustained release of lidocaine. Fourier transform infrared spectroscopy, X-ray diffraction, and Raman spectroscopy confirmed the synthesis of Pluronic® F68-reduced graphene oxide. Transmission electron microscopy showed wrinkled, flat nanosheets with micelles attached. The developed hydrogel showed desirable pH, viscosity, adhesiveness, hardness, and cohesiveness for topical application. The ex vivo release study demonstrated the ability of the Pluronic® F68-reduced graphene oxide hydrogel to prolong release up to 10 h, owing to the strong π-π interactions between the graphene oxide and the lidocaine. In comparison with a commercial lidocaine ointment, the developed graphene oxide hydrogel showed sustained anesthetic effect in the radiant heat tail flick test and sciatic nerve block model. Thus, this study demonstrates the potential of using Pluronic® F68-reduced graphene oxide nanocarriers to realize prolonged effects of local anesthesia for effective pain management.

A reduced graphene oxide-β-cyclodextrin nanocomposite-based electrode for electrochemical detection of curcumin

In this study, a sensitive electrochemical sensor was fabricated based on a beta-cyclodextrin–reduced graphene oxide (β-CD–rGO) nanocomposite for measuring curcumin concentration.

Recovery, reusability and stability studies of beta cyclodextrin used for cholesterol removal from shrimp lipid

Beta cyclodextrin (β-CD) was used for cholesterol removal from shrimp lipid using ethyl acetate and water as solvents. The cholesterol incorporating β-CD complex (β-CD–CL) was collected and β-CD recovery was performed using a β-CD–CL : ethanol mixture (1 : 15 ratio) with the aid of ultrasonication and a water bath at 55 °C for 40 min. Recycled β-CD (R-β-CD) was compared with pure β-CD (P-β-CD) for the reusability of cholesterol removal from shrimp lipid. R-β-CD showed 94% cholesterol removal, while 95% was achieved for P-β-CD. Differential Scanning Calorimetry (DSC) showed a slight decrease in the melting point of R-β-CD. Nevertheless, FTIR and NMR results revealed that functional groups and the proton spectrum of R-β-CD was negligibly altered. Fatty acid contents of treated oil were slightly higher when treated with R-β-CD than those of the lipid subjected to P-β-CD treatment. Reusability of β-CD could be achieved as confirmed by the maintained capacity in cholesterol removal and unaltered structure.

Beta cyclodextrin (β-CD) used for cholesterol removal from shrimp lipid was reused after the cholesterol bound with β-CD was removed. Efficenicy of recycled β-CD was similar to pure β-CD.

Insight into β-cyclodextrin polymer microsphere as a potential filtration reducer in water-based drilling fluids for high temperature application

Controlling the filtration of water-based drilling fluid effectively in high temperature environment is a great challenge in drilling engineering. In this study, β-cyclodextrin polymer microspheres (β-CDPMs) were synthesized by crosslinking between β-cyclodextrin and epichlorohydrin via inverse emulsion polymerization and employed as filtration reducers. The standard American Petroleum Institute filtration test showed that the β-CDPMs can only perform the enhanced filtration control ability at temperatures above 160 °C, and can tolerate the temperature resistance up to 240 °C without significant influence of rheology. As the thermal aging temperature is above 160 °C, numerous nano carbon spheres and nanostructured composites generated due to the occurrence of hydrothermal reaction. These high temperature stable nanoparticles bridged across the nano sized gaps and participated into forming dense filter cake, contributing to excellent filtration control. The filtration control mechanism proposed in this study opened a novel avenue for high temperature filtration control in water-based drilling fluids.

Construction of a water-soluble and photostable rubropunctatin/β-cyclodextrin drug carrier

The purpose of the current study was to construct a β-cyclodextrin drug carrier for rubropunctatin to improve its water solubility and light stability for future cytotoxicity studies. The inclusion complexation behavior of rubropunctatin with β-cyclodextrin was investigated using FESEM, FT-IR and XRD. A molecular docking study was performed to elucidate the most probable inclusion structure. The inclusion complex could be completely dispersed in water and had a small size of 121.87 ± 2.13 nm (n = 3), a good PDI (0.320 ± 0.017), and an acceptable potential value of -27.7 ± 0.32 mV (n = 3). Furthermore, the stability of the rubropunctatin in water under light irradiation was found to be greatly enhanced after being encapsulated in cyclodextrin, and it exhibited a retention rate of over 70% vs. 10.17%. In addition, the cytotoxicity of the inclusion complex was evaluated by MTT assay and Annexin V-FITC/PI detection using cervical adenocarcinoma HeLa cells. The results showed that the inclusion complex had comparable toxicity compared to rubropunctatin solubilized with 0.4% DMSO. More importantly, the formation of the inclusion complex contributed greatly to the intensification of the bioavailability of rubropunctatin because the use of organic solvent was avoided.