The Biological Fate of Pharmaceutical Excipient ß-Cyclodextrin: Pharmacokinetics, Tissue Distribution, Excretion, and Metabolism of ß-Cyclodextrin in Rats.

ß-cyclodextrin has a unique annular hollow ultrastructure that allows encapsulation of various poorly water-soluble drugs in the resulting cavity, thereby increasing drug stability. As a bioactive molecule, the metabolism of ß-cyclodextrin is mainly completed by the flora in the colon, which can interact with API. In this study, understanding the in vivo fate of ß-cyclodextrin, a LC-MS/MS method was developed to facilitate simultaneous quantitative analysis of pharmaceutical excipient ß-cyclodextrin and API dextromethorphan hydrobromide. The established method had been effectively used to study the pharmacokinetics, tissue distribution, excretion, and metabolism of ß-cyclodextrin after oral administration in rats. Results showed that ß-cyclodextrin was almost wholly removed from rat plasma within 36 h, and high concentrations of ß-cyclodextrin distributed hastily to organs with increased blood flow velocities such as the spleen, liver, and kidney after administration. The excretion of intact ß-cyclodextrin to urine and feces was lower than the administration dose. It can be speculated that ß-cyclodextrin metabolized to maltodextrin, which was further metabolized, absorbed, and eventually discharged in the form of CO2 and H2O. Results proved that ß-cyclodextrin, with relative low accumulation in the body, had good safety. The results will assist further study of the design and safety evaluation of adjuvant ß-cyclodextrin and promote its clinical development.

Development of ß-cyclodextrin/polyvinypyrrolidone-co-poly (2-acrylamide-2-methylpropane sulphonic acid) hybrid nanogels as nano-drug delivery carriers to enhance the solubility of Rosuvastatin: An in vitro and in vivo evaluation.

The present study is aimed at enhancing the solubility of rosuvastatin (RST) by designing betacyclodextrin/polyvinypyrrolidone-co-poly (2-acrylamide-2-methylpropane sulphonic acid) crosslinked hydrophilic nanogels in the presence of crosslinker methylene bisacrylamide through free-radical polymerization method. Various formulations were fabricated by blending different amounts of betacyclodextrin, polyvinylpyrrolidone, 2-acrylamide-2-methylpropane sulphonic acid, and methylene bisacrylamide. The developed chemically crosslinked nanogels were characterized by FTIR, SEM, PXRD, TGA, DSC, sol-gel analysis, zeta size, micromeritics properties, drug loading percentage, swelling, solubility, and release studies. The FTIR spectrum depicts the leading peaks of resultant functional groups of blended constituents while a fluffy and porous structure was observed through SEM images. Remarkable reduction in crystallinity of RST in developed nanogels revealed by PXRD. TGA and DSC demonstrate the good thermal stability of nanogels. The size analysis depicts the particle size of the developed nanogels in the range of 178.5 ±3.14 nm. Drug loading percentage, swelling, solubility, and release studies revealed high drug loading, solubilization, swelling, and drug release patterns at 6.8 pH paralleled to 1.2 pH. In vivo experiments on developed nanogels in comparison to marketed brands were examined and better results regarding pharmacokinetic parameters were observed. The compatibility and non-toxicity of fabricated nanogels to biological systems was supported by a toxicity study that was conducted on rabbits. Efficient fabrication, excellent physicochemical properties, improved dissolution, high solubilization, and nontoxic nanogels might be a capable approach for the oral administration of poorly water-soluble drugs.

Development of an LC-MS/MS method for simultaneous quantitative analysis of macromolecular pharmaceutical adjuvant 2-hydroxypropyl-ß-cyclodextrin and active pharmaceutical ingredients butylphthalide in rat plasma.

Hydroxypropyl-ß-cyclodextrin, which possesses a high water solubility and low hemolycity, is widely used as a solubilizer and an excipient. It had also been reported that hydroxypropyl-ß-cyclodextrin has the activity of regulating lipid homeostasis. In order to further understand the metabolism, the primary focus was to establish a quantitative method for hydroxypropyl-ß-cyclodextrin. The analytes were extracted from plasma by protein precipitation with methanol and then carried out on a Waters CORTECS T3 column in the gradient elution of pure water and methanol. Finally, liquid chromatography-tandem mass spectrometry was applied in multiple reaction monitoring mode to complete the quantitative analysis of hydroxypropyl-ß-cyclodextrin. This validated method had been successfully applied to investigate the interaction between hydroxypropyl-ß-cyclodextrin and butylphthalide in vivo by optimizing the extraction reagent, simplifying the experimental procedure, and improving the sensitivity while considering the difference of drug chemical properties. Results showed that the inclusion of hydroxypropyl-ß-cyclodextrin with butylphthalide significantly improved the pharmacokinetic behavior of free body hydroxypropyl-ß-cyclodextrin and 3-n-butylphthalide in vivo. It had been implied that the metabolism of hydroxypropyl-ß-cyclodextrin and the drug active ingredients could impact each other. It will help better application of hydroxypropyl-ß-cyclodextrin and the developed method might lay the foundation for development of hydroxypropyl-ß-cyclodextrin as a treatment drug for brain diseases.

Exploring Charged Polymeric Cyclodextrins for Biomedical Applications.

Over the years, cyclodextrin uses have been widely reviewed and their proprieties provide a very attractive approach in different biomedical applications. Cyclodextrins, due to their characteristics, are used to transport drugs and have also been studied as molecular chaperones with potential application in protein misfolding diseases. In this study, we designed cyclodextrin polymers containing different contents of ß- or γ-cyclodextrin, and a different number of guanidinium positive charges. This allowed exploration of the influence of the charge in delivering a drug and the effect in the protein anti-aggregant ability. The polymers inhibit Amiloid ß peptide aggregation; such an ability is modulated by both the type of CyD cavity and the number of charges. We also explored the effect of the new polymers as drug carriers. We tested the Doxorubicin toxicity in different cell lines, A2780, A549, MDA-MB-231 in the presence of the polymers. Data show that the polymers based on γ-cyclodextrin modified the cytotoxicity of doxorubicin in the A2780 cell line.

Molecular Dynamics Protocols for the Study of Cyclodextrin Drug Delivery Systems.

Hypertension treatment is a current therapeutic priority as there is a constantly increasing part of the population that suffers from this risk factor, which may lead to cardiovascular and encephalic episodes and eventually to death. A number of marketed medicines consist of active ingredients that may be relatively potent; however, there is plenty of room to enhance their pharmacological profile and therapeutic index by improving specific physicochemical properties. In this work, we focus on a class of blood pressure regulators, called sartans, and we present the computational scheme for the pharmacological improvement of irbesartan (IRB) as a representative example. IRB has been shown to exert increased pharmacological action compared with other sartans, but it appears to be highly lipophilic and violates Lipinski rule (MLogP >4.15). To circumvent this drawback, proper hydrophilic molecules, such as cyclodextrins, can be used as drug carriers. This chapter describes the combinatory use of computational methods, namely molecular docking, quantum mechanics, molecular dynamics, and free energy calculations, to study the interactions and the energetic contributions that govern the IRB:cyclodextrin association. We provide a detailed computational protocol, which aims to assist the improvement of the pharmacological properties of sartans. This protocol can also be applied to any other drug molecule with diminished hydrophilic character.

Methyl-beta cyclodextrin and creatine work synergistically under hypoxic conditions to improve the fertilization ability of boar ejaculated sperm.

Although successful fertilization is completed by only 150 sperm in the pig oviduct, more than 50,000 sperms are required to achieve a fertilization rate of more than 70% by pig in vitro fertilization (IVF). In this study, to improve the efficiency of pig IVF, the effects of hypoxic conditions and treatment with creatine and methyl-beta cyclodextrin (MßCD) on the glycolytic pathway were investigated. Under low O2 conditions, zig-zag motility was strongly induced within 30 min; however, the induction disappeared at 60 min. Although caffeine suppressed zig-zag motility under low O2 conditions, creatine induced and sustained zig-zag motility until 120 min. Additionally, pretreatment with MßCD for 15 min greatly enhanced zig-zag motility via ATP production in sperm incubated with creatine under low O2 conditions. Sperm pretreated with MßCD were used for IVF in medium containing creatine under low O2 conditions. A fertilization rate of approximately 70% was achieved with only 1.0 x 104 sperms/mL, and there were few polyspermic embryos. Therefore, our novel method was beneficial for efficient production of pig embryos in vitro. Moreover, the zig-zag motility may be a novel movement which boar capacitated sperm exhibit in the culture medium.

Encapsulating curcumin in ethylene diamine-ß-cyclodextrin nanoparticle improves topical cornea delivery.

Curcumin is a powerful scavenger of reactive oxygen species and could prevent the corneal cells from oxidative damage. However, the clinical efficacy of curcumin is limited by its low aqueous solubility and stability, leading to poor bioavailability. ß-cyclodextrin, with a hydrophilic surface and a hydrophobic cavity and self-assembling properties, can form inclusion complexes with lipophilic drugs such as curcumin for ocular delivery. We synthesized ethylene diamine (EDA)-modified ß-cyclodextrin and prepared the curcumin complexation using the solvent evaporation method. The EDA-ß-cyclodextrin provided a better thermodynamic stability and higher complex yield for curcumin complexes, compared to ß-cyclodextrin, which were demonstrated on the analysis of their van't Hoff plots and phase solubility diagrams. We characterized EDA-ß-cyclodextrin curcumin nanoparticles and determined that the EDA modified ß-cyclodextrin is a more suitable carrier than parental ß-cyclodextrin, using FT-IR, XRD, TEM, and analyses of solubility and storage stability. In addition, the curcumin-EDA-ß-cyclodextrin nanoparticles had better in vitro corneal penetration and 3 -h cumulative flux in a porcine cornea experiment, and displayed an improved biocompatibility, confirmed by the histological examination of porcine corneas and cell viability of bovine corneal epithelial cells. These results together revealed a role of EDA modification in the ß-cyclodextrin carrier, including the improvement of curcumin complex formation, thermodynamic properties, cytotoxicity, and the in vitro corneal penetration. The EDA-ß-cyclodextrin inclusion can provide curcumin a higher degree of aqueous solubility and corneal permeability.

A thermoresponsive hydrophobically modified hydroxypropylmethylcellulose/cyclodextrin injectable hydrogel for the sustained release of drugs.

The objective of this study was to develop a thermoresponsive injectable hydrogel for the sustained release of drugs by taking advantage of host-guest interactions between a hydrophobically modified hydroxypropylmethyl cellulose (HM-HPMC) and cyclodextrin (CD). A thermoresponsive injectable hydrogel was prepared by simply adding CDs to HM-HPMC hydrogel. The HM-HPMC hydrogel was converted into a sol with a low viscosity through host-guest interactions with CDs. The HM-HPMC/ß-CD hydrogel became a gel near body temperature where the host dissociated from the hydrophobic moieties of the polymer in response to the temperature. The yield stress of the HM-HPMC became progressively lower on the addition of ß-CD which was desirable in the case of developing an injectable formulation. When the HM-HPMC/ß-CD hydrogel containing indocyanine green (ICG) was subcutaneously administered to mice, the fluorescence of the ICG remained relatively constant for 24 h after the administration, which was substantially longer than that for ICG alone or an HPMC formulation. The plasma insulin level was maintained for a longer period of time when the HM-HPMC/ß-CD containing insulin was administered and the MRT value was increased by 1.6 times compared to a solution of insulin alone. In addition, the HM-HPMC/ß-CD hydrogel formulation showed a prolonged hypoglycemic effect in response to the insulin which was slowly released from the hydrogel. A thermoresponsive injectable hydrogel was successfully constructed from the highly viscous HM-HPMC and ß-CD, and the resulting formulation functioned as a sustained release carrier for drugs.

Cyclodextrin based unimolecular micelles with targeting and biocleavable abilities as chemotherapeutic carrier to overcome drug resistance.

An amphiphilic star-shaped copolymer ß-CD-g-PCL-SS-PEG-FA, consisting of a ß-cyclodextrin (ß-CD) core as well as grafted with bioreducible disulfide linkage in PCL-SS-PEG multiarms and targeting folic acid (FA) as end moiety, is designed with unimolecular micelles formation ability for targeted transport of chemotherapeutics to drug resistant tumor cells. Firstly, ß-CD was utilized as core to growth PCL arms by ring-opening polymerization (ROP) of ε-CL, before disulfide terminal group transformation to render ß-CD-g-PCL-SS-COOH. Secondly, α-hydroxy-ω-amine protected PEG (HO-PEG-NHBoc) was connected to ß-CD-g-PCL-SS-COOH to obtain amphiphilic ß-CD-g-PCL-SS-PEG, where PCL and PEG were connected via bioreducible disulfide bond. After deprotection of -Boc group, FA was introduced onto the distal end of block arms to obtain the desired ß-CD-g-PCL-SS-PEG-FA copolymer. Because of highly branched core-shell amphiphilic structures, ß-CD-g-PCL-SS-PEG-FA could act as unimolecular micelles. Interestingly, this unimolecular micelle could release the encapsulated drug in a glutathione (GSH) dependent manner due to disulfide linkage. More importantly, this unimolecular micelle could load doxorubicin (DOX) to promote its cellular uptake in multidrug resistance (MDR) protein overexpression tumor cells, by taking the advantage of FA targeting group and intracellular high GSH level in cancer cells. Together with satisfactory biocompatibility, this novel star-like ß-CD-g-PCL-SS-PEG-FA unimolecular micelle could potentially be utilized as targeting nanocarriers in drug resistant cancer therapy.

Co-responsive smart cyclodextrin-gated mesoporous silica nanoparticles with ligand-receptor engagement for anti-cancer treatment.

Combination of both internal- and external-stimuli responsive strategies in nanoplatforms can maximize therapeutic outcomes by overcoming drug efflux-mediated resistance and prolonging sustained release of therapeutic payloads in controlled and sequential manner. Here, we show a light/redox dual-stimuli responsive ß-cyclodextrin (ß-CD)-gated mesoporous silica nanoparticles (MSN) that can effectively load and seal the chemotherapeutics, doxorubicin (DOX), inside MSN with a dual-capped system. The primary gatekeeper was achieved by capping ß-CD via a disulfide linkage. An azobenzene/galactose-grafted polymer (GAP) was introduced to functionalize the MSN surface through host-guest interaction. GAP not only served as a secondary non-covalent polymer-gatekeeper to further prevent molecules from leaking out, but also presented targeting ligand for engagement of the asialoglycoprotein receptor (ASGPR) on hepatocellular carcinoma (HepG2) cells. The controlled and stimuli release of DOX could be realized via dissociation of azobenzene moieties from ß-CD cage upon UV-irradiation, followed by liberation with the endogenous glutathione. The in vitro studies verified the redox-sensitive DOX release behavior, and the UV irradiation could accelerate this process to trigger DOX burst from MSN-ss-CD/GAP. Notably, the DOX@MSN-ss-CD/GAP could more efficiently deliver DOX into HepG2 cells and demonstrate enhanced cytotoxicity as compared with HeLa and COS7 cells. The smart MSN-ss-CD/GAP delivery system holds the potential for universal therapeutic uses in both biomedical research and clinical settings.

Sustained Release of Dexamethasone from Sulfobutyl Ether ß-cyclodextrin Modified Self-Assembling Peptide Nanoscaffolds in a Perinatal Rat Model of Hypoxia-Ischemia.

Inflammation plays a critical role in the development of hypoxia-ischemia (HI) induced newborn brain damage. A localized, sustained delivery of dexamethasone (Dex) through an intracerebral injection could reduce the inflammatory response in the injured perinatal brain while avoiding unnecessary side effects. Herein, investigated using anionic sulfobutyl ether ß-cyclodextrin (SBE-ß-CD) to load Dex in the (RADA)4 nanofiber networks as a means of reducing the inflammatory response to HI injury is investigated. The ionic interaction between SBE-ß-CD and (RADA)4 dramatically affects nanofiber formation and the stability of the nanoscaffold is highly dependent on the SBE-ß-CD/(RADA)4 ratio. It is observed that the Dex release rate is affected by the concentration of SBE-ß-CD and (RADA)4 peptide. A higher concentration of SBE-ß-CD or (RADA)4 results in a higher drug encapsulation efficiency and slower release rate of Dex. This phenomenon may be related to the structure of fiber bundles. Animal studies show that nanoscaffold loaded with Dex inhibits both microglia activation and glial scar formation compared to controls (Dex alone or nanoscaffold alone) within 2 days of injury. It is thought that this is a step toward building a multifaceted nanoscaffold that can be used to treat HI events in perinates.

Brexanolone: First Global Approval.

Brexanolone (ZULRESSO™) is an intravenously administered, small molecule, neuroactive steroid GABAA receptor positive allosteric modulator that was developed by Sage Therapeutics under license to the University of California for the treatment of postpartum depression (PPD). The formulation is a mixture of allopregnanolone, an endogenous inhibitory pregnane neurosteroid, and sulfobutylether-beta-cyclodextrin (a solubilizing agent). In mid-March 2019 brexanolone received its first global approval in the USA for the treatment of PPD in adult women. This article summarizes the milestones in the development of brexanolone leading to its first approval for the treatment of adult women with PPD.

A Supramolecular Nanocarrier for Delivery of Amiodarone Anti-Arrhythmic Therapy to the Heart.

Amiodarone is an effective antiarrhythmic drug used to treat and prevent different types of cardiac arrhythmias. However, amiodarone can have considerable side effects resulting from accumulation in off-target tissues. Cardiac macrophages are highly prevalent tissue-resident immune cells with importance in homeostatic functions, including immune response and modulation of cardiac conduction. We hypothesized that amiodarone could be more efficiently delivered to the heart via cardiac macrophages, an important step toward reducing overall dose and off-target tissue accumulation. Toward this goal, we synthesized a nanoparticle drug carrier composed of l-lysine cross-linked succinyl-ß-cyclodextrin that demonstrates amiodarone binding through supramolecular host-guest interaction as well as a high macrophage affinity. Biodistribution analyses at the organ and single-cell level demonstrate accumulation of nanoparticles in the heart resulting from rapid uptake by cardiac macrophages. Nanoparticle assisted delivery of amiodarone resulted in a 250% enhancement in the selective delivery of the drug to cardiac tissue in part due to a concomitant decrease of pulmonary accumulation, the main source of off-target toxicity.

Quercetin and 3-O-methylquercetin in vitro skin layers permeation/retention from hydrogels: why only a methoxy group difference determines different behaviors?

OBJECTIVES: The present study was designed to verify if quercetin (QCT), a flavonoid with antioxidant and antiviral activity, and 3-O-methylquercetin (3OMQ), a quercetin C3-methoxylated derivative, present differences in their behavior against complexation with ß-cyclodextrin (ß-CD) and the corresponding permeation/retention trhough porcine ear skin, when incorporated into hydroxypropyl methylcellulose (HPMC) or chitosan (CS) hydrogels. METHODS: The influence of ß-CD on the skin permeation/retention of QCT and 3OMQ from hydrogels is comparatively evaluated for both flavonoids using porcine ear skin in Franz cells model. The properties of the two flavonoids using the semi-empirical method Recife Model was studied. KEY FINDINGS: Quercetin presented higher skin retention compared with its C3-methoxy derivative 3OMQ. The best permeation/retention of QCT was observed when it was incorporated into CS hydrogel containing 5% ß-CD, whereas, for 3OMQ, the HPMC hydrogel containing 5% ß-CD was the best formulation. The flavonoids complexation with ß-CD in water occurred preferentially with the insertion of the B ring through the secondary OH rim. CONCLUSIONS: The dynamic molecular modeling revealed that the methyl group at C3 in 3OMQ molecule determined significant difference in its complexation with ß-CD, in comparison to its analogous QCT and that difference is coincident with the permeation behavior of these flavonoids, denoting a possible relationship with their molecular dynamics.

Supramolecularly Engineered NIR-II and Upconversion Nanoparticles In Vivo Assembly and Disassembly to Improve Bioimaging.

Contrast agents for bioimaging suffer from low accumulation at lesion area and high uptake in the reticuloendothelial system (RES). Assembly of nanoparticles in vivo improves their enrichment at tumors and inflamed areas. However, uncontrollable assembly also occurs at the liver and spleen owing to the uptake of nanoparticles by the RES. This is known to probably cause a higher bioimaging background and more severe health hazards, which may hamper the clinical application. Herein, a new near-infrared (NIR)-controlled supramolecular engineering strategy is developed for in vivo assembly and disassembly between lanthanide upconversion nanoparticles and second near-infrared window (NIR-II, 1000-1700 nm) nanoprobes to realize precision bioimaging of tumors. A supramolecular structure is designed to realize assembly via host-guest interactions of azobenzene and ß-cyclodextrin to enhance the retention of NIR-II nanoprobes in the tumor area. Meanwhile NIR-laser-controllable nanoprobes disassembly brings about a reduction in the bioimaging background as well as acceleration of their RES clearance rate. This strategy may also be used in other nano-to-micro-scale contrast agents to improve bioimaging signal-to-noise ratio and reduce long-term cytotoxicity.

Oral insulin delivery by carboxymethyl-ß-cyclodextrin-grafted chitosan nanoparticles for improving diabetic treatment.

In this paper, a new oral insulin formulation, insulin-loaded carboxymethyl-ß-cyclodextrin-grafted chitosan nanoparticles (insulin/CMCD-g-CS NPs), was fabricated by ionic crosslinking technique. The therapeutic efficacy of new formulation was investigated in detail. Firstly, the CMCD-g-CS was synthesized by EDC-mediated esterification reaction. The prepared CMCD-g-CS exhibited favourable loading capacity and encapsulation efficiency of drug. The release experiment in vitro showed that the nanocarrier could efficiently protect encapsulated insulin at simulated gastric environment and release drug in the simulated colonic fluid. The insulin/CMCD-g-CS NPs effectively promoted drug internalization into Caco-2 cells and could reversibly open the tight junction between cells. The oral administration of insulin/CMCD-g-CS NPs could lastingly decrease blood sugar level in diabetic mice. The liver function study verified that the insulin/CMCD-g-CS NPs had not obvious toxicity to experimental mice. Therefore, the CMCD-g-CS could be an effective and safe oral insulin delivery carrier for future clinical application. A new biocompatible polysaccharide nanoparticle was fabricated as oral insulin delivery carrier for improving diabetic treatment.

Molecular encapsulator-appended poly(vinyl alcohol) shroud on ferrite nanoparticles. Augmented cancer-drug loading and anticancer property.

Magnetic nanoparticles (MNPs) have the potency to deliver cancer drugs assisted by the application of a magnetic field. In this paper, we present the design of magnesium ferrite nanoparticles of size suitable for drug delivery. A coating polymer, poly(vinyl alcohol), tethered with a tapered cone-shaped cyclic oligosachcharide, ß-cyclodextrin (ß-CD) is synthesized and used to wrap and disperse the MNPs. The magnetic properties are explored using vibrating sample magnetometry and Mössbauer spectroscopy. The ∑130 nm MNPs, shrouded with the PVA-CD conjugate allows a high amount of the cancer drug, camptothecin, to be loaded on the nanocarrier. Cytotoxicity studies reveal that the loaded drug retains its potency against HEK 293 cells and the cells are sensitive to the treatment by the drug-loaded nanocarrier.

One-pot fabrication of pH/reduction dual-stimuli responsive chitosan-based supramolecular nanogels for leakage-free tumor-specific DOX delivery with enhanced anti-cancer efficacy.

Facile one-pot approach was established to fabricate chitosan-based supramolecular nanogels as pH/reduction dual-stimuli responsive drug delivery system (DDS) for anticancer drug (doxorubicin, DOX), by bioreducible crosslinking of the ß-cyclodextrin modified chitosan (CD-CS) with disulfide bond embedded crosslinker (Ad-SS-Ad) via host-guest inclusion and simultaneous DOX loading. The DOX@Ad-SS-Ad/CD-CS supramolecular nanogels with hydrodynamic diameter (Dh) of 140 nm and drug-loading capacity of 15.9% were obtained with the mass feeding ratio of carrier:DOX at 25:10. They were stable in the simulated physiological medium with premature drug release of only 3% over 60 h, while a high cumulative release up to 82.3% was achieved within 84 h in a sustained manner without initial burst in the simulated tumor intracellular micro-environment. The MTT assays indicated that the blank Ad-SS-Ad/CD-CS supramolecular nanogels were cytocompatible, while the proposed DOX@Ad-SS-Ad/CD-CS supramolecular nanogels possessed the enhanced antitumor efficacy in comparison with the free DOX.

In vitro and in vivo evaluation of a posaconazole-sulfobutyl ether-ß-cyclodextrin inclusion complex.

Posaconazole (PCZ) is a triazole antifungal agent with an extended spectrum of antifungal activity. It is approved for the prophylaxis of invasive fungal infections in patients with neutropenia or in hematopoietic stem cell transplant recipients undergoing high-dose immunosuppressive therapy for graft-vs-host disease, and for the treatment of fungal infections. However, its pharmacological effects are severely limited owing to its poor solubility and low bioavailability. In order to solve these problems, a sulfobutyl ether-ß-cyclodextrin compound was used to prepare an intramuscular injection to improve the bioavailability of posaconazole. The extracorporeal dissolution rate of posaconazole was markedly improved by this inclusion complex with >90% being released within 5 min, and the in vivo pharmacokinetics were studied using a HPLC/MS/MS method for quantifying posaconazole and the posaconazole-sulfobutyl ether-ß-cyclodextrin inclusion complex in rat blood. Posaconazole and an internal standard, itraconazole, were extracted by protein precipitation using acetonitrile. The concentration range of posaconazole was 0.05-4.0 µg/mL with good linearity (r = 0.9980), the peak concentrations of pure posaconazole and the inclusion complex were 0.565 ± 0.102 µg/mL and 1.12 ± 0.091 µg/mL, the values for AUC0-t were 12.2 ± 2.5 and 19.9 ± 2.5 µg h/mL, and the values for AUC0-∞ were 16.4 ± 3.2 and 25.0 ± 3.5 µg h/mL, respectively. The main pharmacokinetics parameters showed significant differences (P < 0.01). Compared with pure posaconazole, the posaconazole-sulfobutyl ether-ß-cyclodextrin inclusion complex markedly improved the bioavailability of posaconazole.

Dual pH-sensitive supramolecular micelles from star-shaped PDMAEMA based on ß-cyclodextrin for drug release.

Star-shaped poly(2-(dimethylamino)ethyl methacrylate) based on ß-cyclodextrin (ß-CD-(PDMAEMA)7) was synthesized by means of atomic transfer radical polymerization (ATRP). Dual pH-sensitive supramolecular micelles were formed from ß-CD-(PDMAEMA)7 and benzimidazole modified poly(ε-caprolactone) (BM-PCL) through the host-guest interactions between ß-CD and benzimidazole. The supramolecular micelles have regular spherical structure with hydrophobic ß-CD/BM-PCL as the core and pH-sensitive PDMAEMA as the shell. The hydrophobic PCL as well as the hydrophobic cavity of ß-CD can efficiently encapsulate doxorubicin (DOX) with the drug-loading content and entrapment efficiency up to 40% and 86%. The drug release from micelles accelerated when the pH decreased from 7.0 to 2.0 and the temperature increased from 25 °C to 45 °C. MTT assay showed that drug loaded supramolecular micelles exhibited excellent anti-cancer activity than free DOX. These supramolecular micelles have promising potential applications as intelligent nanocarriers in drug delivery system.