Solubility of ( ± )-Ibuprofen and S ( + )-Ibuprofen in the Presence of Cosolvents and Cyclodextrins

Aqueous solubility is an important parameter for the development of liquid formulations and in the determination of bioavailability of oral dosage forms. Ibuprofen (IB), a nonsteroidal anti-inflammatory drug, is a chiral molecule and is currently used clinically as a racemate (racIB). However, the S form of ibuprofen or S(+)-ibuprofen (SIB) is the biologically active isomer and is primarily responsible for the anti-inflammatory activity. Phase solubility studies were carried out to compare the saturation solubilities of racIB and SIB in the presence of common pharmaceutical solvents such as glycerol, sorbitol solution, propylene glycol (PG), and polyethylene glycol (PEG 300) over the range of 20% to 80% v/v in aqueous based systems. The solubilities of the two compounds were also compared in the presence of cyclodextrins such as beta cyclodextrin (CD), hydroxypropyl beta cyclodextrin (HPCD), and beta cyclodextrin sulfobutyl ether sodium salt (CDSB) over the range of 5% to 25% w/v. Solubility determinations were carried at 25°C and 37°C. Cosolvents exponentially increased the solubility of both SIB and racIB, especially in the presence of PG and PEG 300. Glycerol was not very effective in increasing the aqueous solubilities of both compounds, whereas sorbitol solution had a minimal effect on their solubility. PG and PEG 300 increased the solubility of SIB by 400-fold and 1500-fold, respectively, whereas the rise in solubility for racIB was 193-fold and 700-fold, respectively, at 25°C for the highest concentration of the cosolvents used (80% v/v). Of the two compounds studied, higher equilibrium solubilities were observed for SIB as compared with racIB. The derivatized cyclodextrins increased the aqueous solubility of racIB and SIB in a concentration-dependent manner giving A_L type of phase diagrams. The phase solubility diagrams indicated the formation of soluble inclusion complexes between the drugs and HPCD and CDSB, which was of 1:1 stoichiometry. The addition of underivatized CD reduced the solubility of racIB and SIB via the formation of an insoluble complex. The S form formed more stable complexes with HPCD and CDSB as compared with racIB. The solubilization process is discussed in terms of solvent polarity and differential solid-state structure of racIB and SIB. The thermodynamic parameters for the solubilization process are presented.     

Linear cyclodextrin-containing polymers and their use as delivery agents

Cyclodextrins, cyclic oligomers of glucose, have been used in pharmaceutical formulations for decades as a result to their biocompatibilities, low toxicities and their abilities to solubilise organic small molecules via inclusion complex formation. The incorporation of cyclodextrins within polymers of numerous types, for use as drug delivery agents, has been explored. Illustrative of the flexibility in polymer chemistry and delivery application that is possible with these materials, two linear cyclodextrin-containing polymers are in preclinical and clinical development for the non-covalent delivery of nucleic acid therapeutics and covalent delivery of a small-molecule drug, respectively. This document provides an overview of the background and progress that has been made with these materials thus far, as well as suggestions for their future development and characterisation.     

环糊精及其衍生物在药物分离分析中的应用进展

近年来,环糊精及其衍生物在药物尤其是手性药物分离分析中的应用受到了广泛关注。本文通过查阅有关文献,对CD及其衍生物在高效液相色谱、气相色谱、毛细管电泳色谱、薄层色谱、超,临界流体色谱、高速逆流色谱以及膜分离等方法中的应用作了系统介绍,具有十分重要的参考价值。     

Cyclodextrins as Supramolecular Recognition Systems: Applications in the Fabrication of Electrochemical Sensors

Supramolecular chemistry, although focused mainly on noncovalent intermolecular and intramolecular interactions, which are considerably weaker than covalent interactions, can be employed to fabricate sensors with a remarkable affinity for a target analyte. In this review the development of cyclodextrin-based electrochemical sensors is described and discussed. Following a short introduction to the general properties of cyclodextrins and their ability to form inclusion complexes, the cyclodextrin-based sensors are introduced. This includes the combination of cyclodextrins with reduced graphene oxide, carbon nanotubes, conducting polymers, enzymes and aptamers, and electropolymerized cyclodextrin films. The applications of these materials as chiral recognition agents and biosensors and in the electrochemical detection of environmental contaminants, biomolecules and amino acids, drugs and flavonoids are reviewed and compared. Based on the papers reviewed, it is clear that cyclodextrins are promising molecular recognition agents in the creation of electrochemical sensors, chiral sensors, and biosensors. Moreover, they have been combined with a host of materials to enhance the detection of the target analytes. Nevertheless, challenges remain, including the development of more robust methods for the integration of cyclodextrins into the sensing unit.     

Evaluation of cholesterol depletion as a marker of nephrotoxicity in vitro for novel β-cyclodextrin derivatives

Cyclodextrins (CDs) have been shown to improve physicochemical and biopharmaceutical properties of drugs when low solubility and low safety limit their use in the pharmaceutical field. Recently, we have developed new multi-substituted-β-CDs, hydroxypropyl-sulfobutyl ether-β-cyclodextrin (HPn-SBEm-β-CD). HPn-SBEm-β-CD exhibit low hemolysis, good solubility, strong inclusion ability, and an appropriate average molecular weight. In this study, we chose two products of HPn-SBEm-β-CD (HP₃-SBE₂-β-CD and HP₂-SBE₃-β-CD) and compared their effects to sulfobutyl ether-β-cyclodextrin (SBE₇-β-CD), methyl-β-cyclodextrin (M-β-CD) and 2,6-di-O-methyl-β-cyclodextrin (DM-β-CD). We evaluated viability, membrane damage, induction of apoptosis and necrosis, cholesterol depletion, and morphological changes in human embryonic kidney 293A cells (HEK293A) in vitro. CDs caused a reduction of cell viability and increased LDH levels in a concentration-dependent manner. The effect of HP₃-SBE₂-β-CD or HP₂-SBE₃-β-CD on cell viability, membrane damage, and the induction of apoptosis and necrosis resembled that of SBE₇-β-CD, whereas the effects were significantly lower for M-β-CD or DM-β-CD. HP₃-SBE₂-β-CD and HP₂-SBE₃-β-CD exhibited morphological changes at high concentrations. In conclusion, the results showed that cholesterol depletion may be as a marker for evaluating the cytotoxicity of novel β-CD derivatives. These results will provide useful information for HPn-SBEm-β-CD as a promising safe adjuvant for intravenous administration in the future.     

Preparation and characterization of mosapride citrate inclusion complexes with natural and synthetic cyclodextrins

The aim of this work was to investigate the inclusion complexes between mosapride citrate and SBE₇β-CD in comparison with the natural β-CD to enhance its bioavailability by improving the solubility and dissolution rate. The complexation efficiency value of SBE₇β-CD was higher than that for β-CD. Solid binary systems of mosapride citrate with CDs were prepared by physical mixing, kneading and freeze-drying techniques at molar ratio of 1:1(drug:CD). Physicochemical characterization of the prepared systems was studied using X-ray diffractometry, differential scanning calorimetry, Fourier-transform infrared spectroscopy and scanning electron microscopy (SEM). Amorphous drug was detectable to large extent in inclusion complexes prepared using the freeze-drying technique. From the dissolution study of different inclusion complexes in simulated saliva solution (pH 6.8), we could concluded that irrespective of the preparation technique, the systems prepared using SBE₇β-CD showed better performance than the corresponding ones prepared using β-CD. In addition, the freeze-drying technique showed superior dissolution enhancement than other methods especially when combined with the SBE₇β-CD     

Cyclodextrin-induced apoptosis in human keratinocytes is caspase-8 dependent and accompanied by mitochondrial cytochrome c release

Cyclodextrins (CDs) are cyclic oligosaccharides that are able to form inclusion complexes with a variety of substances. For pharmaceutical applications, CD-based drug formulations offer important advantages compared with uncomplexed drugs. These include improved water solubility of lipophilic drug molecules, increased chemical stability, as well as enhanced bioavailability and absorption rate. Also, a number of topical formulations for dermal and transdermal drug delivery contain CDs. However, the most frequently used CDs - beta-CD and MbetaCD - are known to extract cholesterol from plasma membranes and thus to cause cellular damage and cell death. In the present study, the influence of various CDs and CD derivatives on the human keratinocyte cell line HaCaT was assessed. We found that beta-CD and MbetaCD induce apoptosis via the activator caspase-8, which subsequently activates the effector caspases-3/-7. Furthermore, beta-CD-induced apoptosis is accompanied by mitochondrial cytochrome c release. A significant shift from mitochondria into the cytosol was found. These findings may provide further rationale to the use of CDs in topical formulations for dermal and transdermal drug delivery or as raw material in order to functionalize textiles for medical applications.     

Cyclodextrins: Their Future in Drug Formulation and Delivery

Pharmaceutical Research - Since their discovery, cyclodextrins and their ability to form inclusion complexes have fascinated chemists, formulators and recently, entrepreneurs. This mini-review has...     

Org 25969 (sugammadex), a selective relaxant binding agent for antagonism of prolonged rocuronium-induced neuromuscular block

Background. Org 25969 is a cyclodextrin compound designed toreverse a rocuronium-induced neuromuscular block. The aim ofthis study was to explore the efficacy, dose–responserelation and safety of Org 25969 for reversal of a prolongedrocuronium-induced neuromuscular block. Methods. Thirty anaesthetized adult patients received rocuronium0.6 mg kg^–1 as an initial dose followed by incrementsto maintain a deep block at a level of <10 PTCs (post-tetaniccounts) recorded every 6 min. Neuromuscular monitoring was carriedout using accelerometry, in a train-of-four (TOF) mode usingTOF-Watch®SX. At recovery of T₂, following at least 2 hof neuromuscular block, patients received their randomly assigneddose of 0.5, 1.0, 2.0, 4.0 or 6.0 mg kg^–1 of Org 25969.Anaesthesia and neuromuscular monitoring were continued fora minimum period of 30 min after Org 25969 administration. Themain end-point of the study was the time to achieve a sustainedrecovery of TOF ratio to 0.9. Patients were followed up for7 days after anaesthesia. Results. The results showed a dose-related decrease in the averagetime taken to attain a TOF ratio of 0.9 from 6:49 (min:s) withthe 0.5 mg kg^–1 dose to 1:22 with the 4.0 mg kg^–1dose. Weighted non-linear regression analysis showed the fastestachievable time to TOF ratio of 0.9 to be 1:35. Org 25969 producedno major adverse effects. Conclusion. Org 25969 effectively reversed a deep and prolongedneuromuscular block induced by rocuronium. The effective reversaldose appears to be 2–4 mg kg^–1.