Phase solubility techniques
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Cites methods from "Phase solubility techniques"
...However, Connors has pointed out that, in general, the most nonpolar portions of guest molecules are enclosed in the cyclodextrin cavity and, thus, hydrophobic interactions must be important in many cyclodextrin complexes[40]....
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...Kc = [DCD] [D][CD] (1) Connors has evaluated the population characteristics of cyclodextrin complex stabilities in aqueous solution[40,41]....
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...It can be written [32,42]: mL + nS (a−mx)(b−nx) Km:n LmSn (x) So that, Km:n = [x] [a − mx]m[b − nx]n (2) In addition, dissociation constant can also be defined: Kd = [a − mx] m[b − nx]n [x] = 1 Kc or 1 Km:n (3) One of the most useful and widely applied analytical approaches in this context is the Phase–solubility method described by Higuchi and Connors[42]....
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...One of the most useful and widely applied analytical approaches in this context is the Phase–solubility method described by Higuchi and Connors [42]....
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1,135 citations
Cites background or methods from "Phase solubility techniques"
...The inclusion ability of DM-β-CD, causing the release of the transporters (P-gp, MRP2) from the apical membranes of monolayers, was reported to be the possible reason for the observed impaired efflux function of the transporters in the presence of the CD....
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...In such cases it is important to use just enough CD to solubilize the drug in the aqueous vehicle since excess may decrease the drug availability (Figure 4).(8,96,97) At low RM-β-CD concentrations, when hydrocortisone was in suspension, increasing the CD concentration increased the drug flux....
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...Reduction of drug crystallinity on complexation or solid dispersion with CDs also contributes to the CD increased apparent drug solubility and dissolution rate.83,87 CDs, as a result of their ability to form in situ inclusion complexes in dissolution medium, can enhance drug dissolution even when there is no complexation in the solid state.75 SBE-β-CD was shown to be an excellent solubilizer for several drugs and was more effective than β-CD but not as effective as DM-β-CD.93 CDs can also act as release enhancers, for example β-CD enhanced the release rate of poorly soluble naproxen and ketoprofen from inert acrylic resins and hydrophilic swellable (high-viscosity hydroxy propyl methyl cellulose [HPMC]) tableted matrices. β-CD also enhanced the release of theophylline from HPMC matrix by increasing the apparent solubility and dissolution rate of the drug.94,95...
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...CD complexation was found to decrease local drug irritation and also modify the time of drug release during GI transit.(8,17)An itraconazole oral preparation containing 40% (wt/vol) of HP-β-CD (with reduced drug irritation) has been commercialized in the United States and Europe....
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...The cytotoxicity order of CDs on the human corneal cell line was found to be α-CD 9 DM-β-CD 9 SBE-β-CD = HP-β-CD 9 γ-CD....
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724 citations
Cites background from "Phase solubility techniques"
...The stoichiometry of drug–CD complexes and the numerical values of their stability constants are frequently obtained from phase-solubility diagrams where the drug solubility is monitored as a function of total CD added to the complexation medium as shown in Figure 2.([20,41,42]) Linear phase-solubility diagrams (AL-type) indicate that the complex is first order with respect to the CD (n = 1 in Equation 1) and first or higher order with respect to the drug (m 1)....
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...Plots of total drug solubility (Stot) vs total amount of dissolved cyclodextrin, and their classification according to Higuchi & Connors.([41]) 1612 Journal of Pharmacy and Pharmacology 2010; 62: 1607–1621...
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719 citations
562 citations
Cites background from "Phase solubility techniques"
...8 (Moffat et al., 2004)) and waterinsoluble compound (S0 = 1 g/ml at pH 11.9) with large aromatic planar regions, or physicochemical char3) (Higuchi and Connors, 1965)....
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...ThenK1:1 is calculated from the slope andS0 (Higuchi and Connors, 1965): K1:1 = Slope S0(1 − Slope) (3) The observed value ofK1:1 is most often between 50 and 2000 M−1 with a reported mean values of 129, 490 and 355 M−1 for the parent -, - and -cyclodextrin, respectively (Connors, 1995)....
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