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Iodine around us
Published in Tatsuo Kaiho, Iodine Made Simple, 2017
Cyclodextrin is an oligosaccharide of 6–8 continuous circular loops of glucose and is called a cyclic oligosaccharide (cycloamylose). Cyclodextrin molecules have a cylindrical shape with the edge of one side slightly narrowed, resembling a bucket. The inside of the molecule is hydrophobic and the outside is hydrophilic. The internal cavity has the ability to capture other molecules.
Investigating the penetrating potential of nanocomposite β-cycloethosomes: development using central composite design, in vitro and ex vivo characterization
Published in Journal of Liposome Research, 2018
Nida Akhtar, Anurag Verma, Kamla Pathak
Optimization studies conducted on blank β-cycloethosomes revealed the factors that affected vesicular development and assisted in the selection of various levels of optimized factors. From the photomicrographs (Figure 1) of preliminary studies, β-cycloamylose was optimized as an appropriate carrier among α, β, γ-cycloamylose (Figure 1). As vesicles prepared with β-cycloamylose (BC) were of uniform size with definite boundaries (Figure 1B). BC guided the formation of vesicles by providing rigidity to the vesicular membrane and molecular entrapment might occur at the interfacial surface of lipid bilayer and hydroethanolic region. The hydrophilic and hydrophobic nature of BC is thought to be responsible for molecular alignment at the interface as well as in the lipid bilayer (Loftsson et al., 2005). After selecting optimum type of cycloamylose, its appropriate concentration was recorded. In vitro adsorption studies were conducted to optimize the stirring time. The generated adsorption profile (Figure 2A) showed an increase in percent drug adsorbed with time, with constant adsorption after 1 h. The drug adsorbed at 1 h (57.0 ± 1.21%; Table 4) was found to be non-significantly (p > 0.05) different from that adsorbed at 2 h (59.0 ± 1.32). Thus, 1 h was selected as an optimum time for stirring. As stirring of the mixture at the time of vesicle development is observed to be an important aspect that affects the entrapment efficiency. Thus, drug incorporated in a vesicle might be entrapped on to the lipid bilayer or in the ethanolic core. Fluocinolone acetonide, being a lipophilic drug (log P 2.48, Schaefer et al., 2013) gets adsorbed on the phospholipid bilayer depending on the stirring conditions. Hence, in vitro adsorption analysis was performed.
Solubility enhancement of mefenamic acid by inclusion complex with β-cyclodextrin: in silico modelling, formulation, characterisation, and in vitro studies
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2021
Dounia Sid, Milad Baitiche, Zineb Elbahri, Ferhat Djerboua, Mokhtar Boutahala, Zouhair Bouaziz, Marc Le Borgne
Actually, many efficiency issues caused by low solubility drugs are highlighted in recent works, for instance, according to Kalepu and Nekkanti3, more than 80% of drugs are sold as tablets, in which 40% have low water solubility. The same study illustrates more serious situation concerning R&D drug candidates, in which 90% could fail due to low solubility problems. However, to improve the dissolution profile of poorly soluble drugs, various approaches are proposed such as particle size reduction4, drug dispersion in carrier5, modification of crystal habit6, use of surfactant7, self-emulsifying formulations8, and complexation with cyclodextrins (CDs)9. This later is one of the frontier techniques that are employed in almost 56 pharmaceutical products10, where these oligomers obtained from enzymatic degradation of starch are exploited. These cycloamyloses are composed of D-glucopyranoside units linked by α(1 → 4)-glycosidic bonds. Typical native CDs involve six, seven, or eight glucose units, denoted α-, β- and γ-CDs, respectively. CDs belong to cage molecules family due to their hydrophobic cavity structure, and hydrophilic outer surface. Indeed, the most significant characteristic of CDs is their ability to form inclusion complexes with various molecules through host–guest interactions11,12. These inclusion complexes have been revealed to improve the apparent stability, solubility, dissolution rate, and bioavailability of the guest bioactive molecules13–16. Among various CDs, β-CD is the most frequently used in pharmaceutical excipient due to its wide availability, low cost, excellent biocompatibility, preferred cavity dimension, and wide regulatory acceptance17. We note that two other naturally occurring CDs (α- and γ-CDs) are more cost-effective compared to β-CD. Moreover, a recent report provided that a β-CD derivative known as the hydroxypropyl-β-CD, even though it has a better solubility than β-CD, is undesirable due to its toxicity18.