Host-guest stoichiometry affects the physicochemical properties and releases kinetics of beta-cyclodextrin/ ferulic acid inclusion complexes

An inclusion system of embedding ferulic acid into β-cyclodextrin (FACD) with different host-guest stoichiometry was prepared by a co-precipitation method. Then, the physicochemical properties and release kinetics of the FACD...

Bisphenol A Adsorption on Silica Particles Modified with Beta-Cyclodextrins

This study presents the synthesis of silica particles bearing two beta-cyclodextrin (BCD) (beta-cyclodextrin-BCD-OH and diamino butane monosubstituted beta-cyclodextrin-BCD-NH2). The successful synthesis of the BCD-modified silica was confirmed by FT-IR and TGA. Using contact angle measurements, BET analysis and SEM characterization, a possible formation mechanism for the generation of silica particles bearing BCD derivatives on their surface was highlighted. The obtained modified silica displayed the capacity to remove bisphenol A (BPA) from wastewater due to the presence of the BCD moieties on the surface of the silica. The kinetic analysis showed that the adsorption reached equilibrium after 180 min for both materials with qe values of 107 mg BPA/g for SiO2-BCD-OH and 112 mg BPA/g for SiO2-BCD-NH2. The process followed Ho’s pseudo-second-order adsorption model sustaining the presence of adsorption sites with different activities. The fitting of the Freundlich isotherm model on the experimental results was also evaluated, confirming the BCD influence on the materials’ adsorption properties.

DEVELOPMENT OF OPTIMAL COMPOSITION FORMULATION OF RESVERATROL AND SOLUBILISERS

Introduction. Increasing of poorly soluble pharmaceutical substances bioavailability is one of important problems of pharmaceutical technology. Resveratrol is a plant origin polyphenol with a broad spectrum of biological effects. However, due to poor solubility and, as a result, low bioavailability, it is not promising for the development of oral drugs. Thus, today resveratrol is presented only as a biologically active substance that is component of biologically active food supplements.The objective of the research is selection of the optimal solubilizer to increase the solubility of resveratrol by determining the solubilization parameters.Materials and methods. The spectrophotometric characteristics of resveratrol were studied using three groups of solubilizers: poloxamers, polysorbates and cyclodextrins. Studies were carried out in 50 mM hydrochloric acid buffer(pH 1.2) and 50 mM phosphate buffer(pH 6.8). Spectrophotometric measurements were carried out on a spectrophotometer UV/VIS-3600 Shimadzu (Japan) in the wavelength range of 220–380 nm. The effect of solubilizers on the spectrophotometric characteristics of resveratrol was determined in buffer solutions containing the solubilizer and resveratrol in significantly less concentration of its own solubility in water. The used multiple excess of the solubilizer ensured the finding of all resveratrol in a solubilized form. During the determining parameters of solubilization, buffer solutions containing from 2 to 10 mM solubilizers were added to the obviously excess of resveratrol. The indicated amount of resveratrol ensured the presence of its precipitate in all experimentsto determine the completeness of solubilization of the studied polyphenol.Results. Based on the obtained spectrophotometric characteristics of solubilizers solutions with resveratrol, the most effective for the further development of solid dosage forms for oral administration are poloxamer 407, polysorbate 80 and modified methyl-beta-cyclodextrin, which ensure complete dissolution of resveratrol when its content in the composition with a solubilizer is about 10 %.Conclusion. Based on the data obtained on the spectrophotometric characteristics of resveratrol using solubilizers, it can be argued that it is possible to create drugs with improved solubility of the studied polyphenol. On the basis of its compositions with poloxamer 407, polysorbate 80 and modified methyl-beta-cyclodextrin, with the selection of appropriate excipients, solid dosage forms for oral intake can be developed.

pH-responsive polymer-based biomacromolecule nanosponges as biodegradable carriers for DOX delivery

Cellulose is the most abundant renewable biomaterial on earth and beta-cyclodextrin (BCD) is among the most commonly used biocompatible drug encapsulation agents. Combining these bio-organic materials is a very powerful approach to greatly enhance the bioavailability of many drugs. These systems also allow for optimal selective drug release profiles, high biocompatibility, as well as “green nanomedicine” approaches that are eco-friendly in their synthesis and have minimal ecological toxicity. herein, we designed a new type of green and biopolymer-based nanosponge drug carriers which is polymerized by crosslinking beta-cyclodextrin ethylene diamine (βCD-EDA) with bifunctional hairy nanocellulose (BHNC). BHNC contains, besides aldehyde groups, carboxyl groups which can react with amino groups in βCD-EDA. Firstly, the crosslinker βCD-EDA was obtained through a simple nucleophilic substitution reaction between beta-cyclodextrin carbonyl imidazole (βCD-CI) and ethylene diamine (EDA). Secondly, BHNC was functionalized with the crosslinker βCD-EDA through a facile nucleophilic substitution crosslinking reaction of the BHNC activated carboxyl groups by the amines of βCD-EDA. We refer to the polymerized highly crosslinked BHNC-βCD-EDA network as BBE. Various ratios of βCD-EDA and BHNC were polymerized with the help of DMTMM as an activator, which resulted in different morphological shapes of BBE, and thus in different release profiles and pH-responsiveness. Unlike other polymer-based βCDs and nanosponges, these new types of crosslinked polymer were prepared in a green and safe solvent (water) and with very short reaction times and at low temperatures. Finally, the BBE polymers were tested as biocompatible nanocarriers for controllable doxorubicin (DOX) delivery. These hyper crosslinked polymers show a high capacity for loading DOX with extended drug release. Furthermore, breast cancer cell cultures show lower cell viability when DOX was loaded in various BBEs than control samples or DOX alone, indicating that our DOX-BBE drug delivery systems are better anticancer agents than DOX alone.

Measurements From Ears With Endolymphatic Hydrops and 2-Hydroxypropyl-Beta-Cyclodextrin Provide Evidence That Loudness Recruitment Can Have a Cochlear Origin

Background: Loudness recruitment is commonly experienced by patients with putative endolymphatic hydrops. Loudness recruitment is abnormal loudness growth with high-level sounds being perceived as having normal loudness even though hearing thresholds are elevated. The traditional interpretation of recruitment is that cochlear amplification has been reduced. Since the cochlear amplifier acts primarily at low sound levels, an ear with elevated thresholds from reduced cochlear amplification can have normal processing at high sound levels. In humans, recruitment can be studied using perceptual loudness but in animals physiological measurements are used. Recruitment in animal auditory-nerve responses has never been unequivocally demonstrated because the animals used had damage to sensory and neural cells, not solely a reduction of cochlear amplification. Investigators have thus looked for, and found, evidence of recruitment in the auditory central nervous system (CNS). While studies on CNS recruitment are informative, they cannot rule out the traditional interpretation of recruitment originating in the cochlea.Design: We used techniques that could assess hearing function throughout entire frequency- and dynamic-range of hearing. Measurements were made from two animal models: guinea-pig ears with endolymphatic-sac-ablation surgery to produce endolymphatic hydrops, and naïve guinea-pig ears with cochlear perfusions of 13 mM 2-Hydroxypropyl-Beta-Cyclodextrin (HPBCD) in artificial perilymph. Endolymphatic sac ablation caused low-frequency loss. Animals treated with HPBCD had hearing loss at all frequencies. None of these animals had loss of hair cells or synapses on auditory nerve fibers.Results: In ears with endolymphatic hydrops and those perfused with HPBCD, auditory-nerve based measurements at low frequencies showed recruitment compared to controls. Recruitment was not found at high frequencies (> 4 kHz) where hearing thresholds were normal in ears with endolymphatic hydrops and elevated in ears treated with HPBCD.Conclusions: We found compelling evidence of recruitment in auditory-nerve data. Such clear evidence has never been shown before. Our findings suggest that, in patients suspected of having endolymphatic hydrops, loudness recruitment may be a good indication that the associated low-frequency hearing loss originates from a reduction of cochlear amplification, and that measurements of recruitment could be used in differential diagnosis and treatment monitoring of Ménière's disease.