Pharmacokinetic analysis and optimization of hydroxycamptothecin-loaded nanoparticles for liver targeting

In this paper, a pharmacokinetic model to describe the tissue distribution process of nanoparticles was established. To test the possibility of the model, nanoparticles composed of poly(butylcyanoacrylate) and hydroxypropyl-β-cyclodextrins (HP-β-CD) was prepared with a poorly soluble anticancer drug, hydroxycamptothecin (HCPT). Characteristics were determined including particle's size, morphology and in vitro release. The tissue distribution of nanoparticles was also studied. Further, mathematical equation was fitted to the curve of drug concentration-time in liver of hydroxycamptothecin-loaded nanoparticles and the pharmacokinetic parameters of liver were obtained. The effectiveness of hydroxycamptothecin-loaded nanoparticles for liver targeting was evaluated. The results showed that nanoparticles composed of poly(butylcyanoacrylate) and hydroxypropyl-β-cyclodextrins (HP-β-CD) exhibited enhanced liver targeting in rats after i.v. injection. More importantly, the pharmacokinetic parameters (transport constant from blood to target organ KT, drug release rate from nanoparticles Kr and drug elimination constant in target organ Ke) provided some quantitative measure of liver distribution and were useful guidelines for development of targeted drug delivery systems.     

Solubility, 1H-NMR,and Molecular Mechanics of Mebendazole with Different Cyclodextrins

The solubility behavior and binding constants (K_ass) of mebendazole with α-, β-, γ-, and hydroxypropyl-β-cyclodextrins (HP-β-CD) have been investigated in simulated intestinal juice by the Higuchi and Connors method. A_L diagrams have been obtained. The equilibrium has also been studied in simulated gastric fluid with HP-β-CD. The phase solubility, ¹H-NMR, and molecular mechanics studies revealed the formation of a 1:1 complex.     

Dissolution enhancement of cefdinir with hydroxypropyl-β-cyclodextrin

The solid state properties and dissolution behavior of binary systems of cefdinir (CEF) with hydroxypropyl-β-cyclodextrin (HP-β-CD) were investigated. CEF-HP-β-CD interaction in the solution state was studied by phase-solubility analysis and demonstrates the ability of HP-β-CD to complex with CEF giving A_L type profile with 65.28?±?1.3?M^?1 stability constant. The freeze drying technique was adopted to prepare binary systems of CEF with HP-β-CD in 1:1 molar ratio. The solid inclusion was characterized by fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray powder diffractometry (XRD), and scanning electron microscopy (SEM). Aqueous solubility of CEF-HP-β-CD inclusion complex was 2.36-fold of pure CEF. The dissolution profiles of inclusion complexes were determined and compared with those of CEF alone and their physical mixtures. The dissolution rate of inclusion complex was superior than the CEF alone. These approaches indicated that CEF was able to form an inclusion complex with HP-β-CD, and the inclusion compounds exhibited different spectroscopic features and properties.     

Physicochemical study on microencapsulation of hydroxypropyl-β-cyclodextrin in dermal preparations

Objective: To investigate the effect of hydroxypropyl-β-cyclodextrin (HP-β-CD) concentration on the physicochemical properties of the sunscreen agents, namely oxybenzone (Oxy), octocrylene (Oct), and ethylhexyl-methoxy-cinnamate (Cin), in aqueous solution and cream formulations. Methods: The inclusion complexes of sunscreen agents with hydroxypropyl-β-cyclodextrin (HP-β-CD) in aqueous solution and solid phase were studied by UV-vis spectrophotmetery, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and 13C-NMR techniques. The photodegradation reaction of the sunscreen agents' molecules in lotion was explored using UV-vis spectrophotometry and high-performance liquid chromatography (HPLC). Results: The formation of the inclusion complexes was confirmed experimentally using DSC, SEM, and 13C-NMR. The results of spectrophotometric and HPLC studies have shown that the inclusion complexation with HP-β-CD has the potential to enhance the photostability of the selected sunscreen agents in lotion. HPLC results indicated that HP-β-CD has approximately increases the photostability of Oct by six- to eightfold. Moreover, the presence of HP-β-CD in lotion controlled the isomerization process of Cin to a certain degree, which was found to be a function of the amount of HP-β-CD added. Conclusions: It has been demonstrated that the photostability of the tested sunscreen agents has been enhanced upon forming inclusion complexes with HP-β-CD in lotion. The results of this study demonstrate that HP-β-CD can be utilized as photostabilizer additive for enhancing the photostability of the sunscreen agents' molecules.     

A novel ion-activated in situ gelling ophthalmic delivery system based on κ-carrageenan for acyclovir

The aim of this study was to prepare and evaluate ion-activated in situ gel ophthalmic drug delivery system based on κ-carrageenan (KC), using acyclovir as a model drug, hydroxypropyl methylcellulose (HPMC) as the viscosity agent and hydroxypropyl-β-cyclodextrin (HP-β-CD) as the penetration enhancer. The two ternary phase diagrams exhibited the effect of K⁺ and Ca²⁺ on the sol-to-gel transition, which turned out that KC was more sensitive to K⁺. The optimal ophthalmic matrix (prepared from KC and HPMC) was optimized with in vitro drug release test. The apparent permeability coefficient of acyclovir under 2% HP-β-CD was found to have dramatically increased (2.16-ploid) than that of conventional eye drops (p?in situ gel based on KC significantly delayed drug release and its bioavailability could be improved in comparison with the conventional eye drops. Hence, it has the potential to be a novel kind of ocular drug delivery system.     

Inclusion Complexation of Lorazepam with Different Cyclodextrins Suitable for Parenteral Use

The development of a parenteral lorazepam formulation, using cyclodextrins (CDs) as inclusion complexation agents, was investigated. CDs suitable for parenteral injection, i.e., hydroxypropyl-β-cyclodextrin (HP-β-CD), hydroxypropyl-γ-cyclodextrin (HP-γ-CD), sulfobutylether-7-β-cyclodextrin (SBE-7-β-CD), and maltosyl-β-cyclodextrin (malt-β-CD) were studied for the possibility to increase the solubility of lorazepam. Lorazepam interacted with all tested CD derivatives and 1:1 complexes are formed. HP-β-CD exerts the highest solubility improvement, reaching about 6 mg/ml lorazepam in 30% (w/v) CD solution. When using SBE-7-β-CD or malt-β-CD only half of that concentration can be dissolved. HP-γ-CD interacts much less with lorazepam. Parenteral solutions with 4 mg/ml in 30% (w/v) HP-β-CD solution, with 2 mg/ml in 30% (w/v) SBE-7-β-CD, and with 2 mg/ml lorazepam in 15% (w/v) HP-β-CD, were prepared. Sterile filtration of the formulation needs to be applied because of massive degradation of lorazepam during autoclaving. No precipitation is observed after dilution of the different formulations with (physiological) water or with 5% dextrose in water, which proves their suitability for administration with perfusions. The stability of the preparations was investigated in aqueous medium. During the first month, in all solutions more than 90% of lorazepam remained; after 3 months, less than 60% of lorazepam remained in the solutions with 15% (w/v) HP-β-CD and around 65–70% in the solutions with 30% (w/v) of CDs. Because of this short stability time, the preparations need to be lyophilized.     

Transdermal Iontophoresis and Skin Retention of Piroxicam from Gels Containing Piroxicam : Hydroxypropyl-β-cyclodextrin Complexes

Iontophoretic transport of piroxicam (Px) across porcine ear skin in vitro was investigated. Cathodal iontophoresis of negatively charged Px was carried out from gel formulations containing Px as an inclusion complex with hydroxypropyl-β-cyclodextrin (HP-β-CD). From the gels, following a 7 h application period at 0.4 mA/cm², iontophoresis delivered 3.4 times more drug than passive diffusion. The formation of Px : HP-β-CD complexes did not increase the iontophoretic Px flux through the skin. However, Px complexation with HP-β-CD allowed us to increase the drug concentration in the gel; because of that, the amount of Px transported across the skin increased considerably. After iontophoretic experiments, the amount of Px retained in skin seemed to be related to the flux values obtained in each case. Skin pretreatment with 20% HP-β-CD, tested passively and iontophoretically for 3 h, followed by the application of gel containing Px : HP-β-CD complexes, showed no enhancing capacity in any case. The amount of Px retained in the skin after pretreatment experiments was found to be very similar to that obtained without skin pretreatment and was observed to be related to the Px flux through the skin.     

Development of a Cyclodextrin-Based Nasal Delivery System for Lorazepam

A new drug delivery system containing hydroxypropyl-β-cyclodextrin (HP-β-CD) and a mucoadhesive polymer was developed with the aim to overcome the limitations connected with the nasal application of drugs with low water solubility. Lorazepam, free or as cyclodextrin inclusion complex, was loaded into mucoadhesive microparticles by spray drying, using hydroxypropylmethyl cellulose (HPMC), carbomer, and HPMC/carbomer interpolymer complex (IPC) as mucoadhesive components. Differential scanning calorimetry (DSC) indicated the presence of drug crystalline areas in microparticles loaded with free lorazepam, whereas in those loaded with HP-β-CD inclusion complex, the drug was amorphous. Zeta potential measurement revealed that the polymer was the main component on the surface of the microparticles. The swelling rate and mucoadhesive properties of the microparticles were determined by the polymer type used in formulation. IPC- and carbomer-based microparticles showed superior swelling rate and mucoadhesion compared with the HPMC-based microparticles (p < .05). Drug loading into the polymer matrix decreased the swelling rate as well as the mucoadhesive properties of microparticles (p < .05), whereas the presence of HP-β-CD in the matrix did not induce any additional reduction of those parameters (p > .05). The in vitro dissolution studies demonstrated that the microparticles containing the lorazepam inclusion complex displayed 1.8–2.5 times faster drug release compared with those containing free lorazepam. The change in the drug release rate could be connected with improved drug solubility inside the polymer matrix due to inclusion complex formation, as well as to the reduction in crystallinity following complexation, as confirmed by DSC studies.     

Inclusion complexes of fluorofenidone with β-cyclodextrin and hydroxypropyl-β-cyclodextrin

Background: Fluorofenidone is a novel antifibrotic drug and its aqueous solubility is low. Aim: This study was to prepare and characterize inclusion complexes of fluorofenidone (AKF-PD) with β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD). Method: The AKF-PD/cyclodextrins (CDs) inclusion complexes were prepared by coprecipitation and freeze-drying, respectively. The solubility enhancement of AKF-PD was evaluated by phase solubility method. Inclusion complexation in solid phase was studied by X-ray diffraction (XRD) and differential thermal analysis (DTA). The dissolution profiles of AKF-PD/CDs inclusion complexes were investigated and compared with those of their physical mixtures and AKF-PD alone. Results: The phase solubility diagrams of AKF-PD with β-CD and HP-β-CD were of A_L-types, and the solubility of AKF-PD could be increased by 51.5% for β-CD at 0.014 M and 794.0% for HP-β-CD at 0.254 M. The results from XRD and DTA suggested that AKF-PD could form inclusion complex with β-CD or HP-β-CD. The dissolution rate of AKF-PD from the inclusion complexes was much more rapid than AKF-PD alone. Conclusions: The formulation of AKF-PD/CDs inclusion complexes showed superior performance in improving dissolution properties of AKF-PD.     

Preparation of curcumin-hydroxypropyl-β-cyclodextrin inclusion complex by cosolvency-lyophilization procedure to enhance oral bioavailability of the drug

Abstract

The curcumin (CUR)-hydroxypropyl-β-cyclodextrin (HP-β-CD) inclusion complex (CUR-HP-β-CD) was prepared to erase its therapeutic restrictions of poor aqueous solubility and low oral bioavailability. CUR-HP-β-CD was prepared by a simple procedure of water-ethanol cosolvent incubation-lyophilization which may be suitable for scale up production, and characterized by Fourier transform-infrared spectroscopy (FT-IR), powder X-ray diffractometry (PXRD), differential scanning calorimetry (DSC), phase solubility method and dissolution study; the in vitro cytotoxicity was assayed by MTT, whereas the in vivo pharmacokinetics was tested by HPLC in rats receiving formulations via intravenous and oral administration, respectively. CUR was successfully encapsulated in HP-β-CD with a loading capacity of about 1:7 of CUR to HP-β-CD mole ratio, which remarkably enhanced drug water solubility and maintained well the antitumour activity of CUR. The CUR-HP-β-CD and free CUR have a similar pharmacokinetic behaviour in rats after intravenous administration; however, the oral bioavailability of CUR was enhanced to 2.77-fold by the HP-β-CD. The CUR-HP-β-CD can be successfully prepared by a simple method, which may be feasible for industrial scaling up, to remarkably increase drug water solubility and oral bioavailability while maintaining its bioactivity and may be a promising therapeutic preparation.     

Comparison of cefpodoxime proxetil release and antimicrobial activity from tablet formulations: complexation with hydroxypropyl-β-cyclodextrin in the presence of water soluble polymer

This study aims to prove the complexation of cefpodoxime proxetil (CP) by hydroxypropyl-β-cyclodextrin (HP-β-CD) in the presence of sodium carboxymethyl cellulose (Na CMC), and makes a comparison of commercial tablets by dissolution and antimicrobial activity studies. The CP--HP-β-CD complex was prepared by kneading method and characterized by SEM, FTIR and DSC. The solubility method was used to investigate the effect of HP-β-CD and Na CMC on the solubility of CP. The complex tablets were prepared using direct compression method. Dissolution studies were performed with complex tablets and commercial tablets in pH 1.2, 4.5, 6.8 and 7.4 buffer solutions. It was observed that complexation occurred in all formulations, and HP-β-CD is able to increase CP solubility and dissolution rate of CP was improved from complex tablets, when compared with commercial tablets. Furthermore, the antimicrobial activity studies revealed that the CP--HP-β-CD complex and complex tablets were shown to have more effective antimicrobial activity than commercial tablets. It is evident from the results that complexation with HP-β-CD in the presence of Na CMC is feasible way to prepare a more efficient tablet formulation with improved dissolution and antimicrobial activity.     

Dissolution Characteristics of Nifedipine Complexes with β-Cyclodextrins

Abstract

Formation of nifedipine complexes with β-cyclodextrin, hydroxypropyl-β-cyclodextrin, and DIMEB in solution was studied by the phase solubility method. Solid complexes of nifedipine were prepared by partial and complete solubilization of nifedipine using the freeze- and spray-drying techniques. The complexation led to an improvement in the dissolution rate of the drug. The relative potency of β-cyclodextrins to enhance the dissolution rate of nifedipine was in order: p-cyclodextrin < hydroxypropyl-β-cyclodextrin < DIMEB, which clearly fits the magnitude of stability constant data of the complexes. The dissolution rates of the free drug, complexes, and physical mixture of drug and cyclodextrins from constant surface area disks were also investigated.     

Characterization and In Vivo Evaluation of an Inclusion Complex of Oridonin and 2-hydroxypropyl-β-cyclodextrin

Oridonin, a diterpenoid, is a sparingly soluble compound and its aqueous solubility can't meet the requirement of clinical intravenous administration. This study was, accordingly, to prepare an inclusion complex of oridonin and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) by lyophilization to improve its apparent solubility. The solubility enhancement of oridonin was evaluated by phase solubility method, and the phase solubility curve displayed a typical A_L-type, indicating the formation of 1:1 inclusion complex. The formation of inclusion complex was confirmed by DSC, XRD, FTIR, and NMR, and thereby two possible inclusion modes were inferred. In vivo studies demonstrated that HP-β-CD had no significant effect on the plasma pharmacokinetic behaviors of oridonin following i.v. administration to rats, but the inclusion complex tended to decrease the distribution of oridonin in heart, spleen, and kidney and increase that in lung in mice, compared to that of free drug.     

Preparation and cyclodextrin assisted dissolution rate enhancement of itraconazolium dinitrate salt

The poor solubility of itraconazole (ITR) results in its variable oral absorption and bioavailability and has also proven to be a major setback in developing an efficient oral delivery system. To improve its solubility and dissolution profile, itraconazolium dinitrate salt (ITRDNT) was prepared and characterized using various spectral and thermal techniques. The morphology of the salt was studied using optical and scanning electron microscopy (SEM). Broth microdilution assay demonstrated antifungal efficacy of ITRDNT similar to ITR against four different fungal strains namely, Asparagillus fumigatus, Microsporum canis, Microsporum gypsum and Trichophyton rubrum. The salt exhibited better solubility profile than ITR in water and a number of pharmaceutical solvents. Dissolution studies revealed the total amount of drug released from ITRDNT in 3 h was four times greater than that of ITR. To further improve dissolution characteristics, the physical mixtures of ITR and ITRDNT with two cyclodextrins, β-cyclodextrin (β-CD) and HP-β-cyclodextrin (HP-β-CD) were prepared and their molar ratios were optimized. It was observed that about 75% of drug was released in 30 min from 1:3 molar ratio of ITRDNT and HP-β-CD physical mixture, which was distinctly higher than ITR commercial capsules (70%). Owing to its facile and economical preparation and substantially better in vitro release profile, the ITRDNT and its CD physical mixtures could be better and cost effective alternatives to ITR and commercial ITR capsules.     

Inclusion complexes of bendamustine with β-CD,HP-β-CD and Epi-β-CD: in-vitro and in-vivo evaluation

Abstract

The objective of the present work was to investigate the inclusion behavior of bendamustine (BM) with β-cyclodextrin and its hydrophilic derivatives (HP-β-CD and Epi-β-CD) for the enhancement of aqueous solubility, dissolution and bioavailability. The supramolecular binary complexes were prepared by three different methods, viz. physical mixture (PM), kneading (KND) and co-evaporation (COE). Phase-solubility study revealed the higher solubilizing and complexing ability of polymerized cyclodextrin (K_s?=?645?M^?1) than parent cyclodextrin (K_s?=?43?M^?1) and chemically derived cyclodextrin (K_s?=?100?M^?1). Meanwhile, the solubility of BM was significantly enhanced in phosphate buffer of pH 6.8, which was 24.5 folds greater compared with the phosphate buffer pH 4.5 and four times greater than aqueous medium. The dissolution efficiency was found to be highest for BM: Epi-β-CD complex (87%) compared to BM: HP-β-CD complex (84%), BM: β-CD (79%) and pure drug (20%). In-vivo pharmacokinetic study revealed that the bioavailability of BM was enhanced 2.55 times on complexation with Epi-β-CD using KND method. The t_1/2 of BM was increased from 34.2?min to approximately 75.7?min, allowing the absorption for longer time. The order of increase in solubility, dissolution and bioavailability of BM was KND?>?COE?>?PM?>?pure drug. Thus, the strategy of host–guest inclusion was very effective and could be successfully used in the development of suitable pharmaceutical dosage form with enhanced therapeutic activity.     

Evaluation of Stereoselective Dissolution of Racemic Salbutamol Matrices Prepared with Commonly Used Excipients and 1H-NMR Study

The purpose of this work was to examine the in vitro enantioselective dissolution of salbutamol from matrix tablets containing various chiral excipients, such as γ-cyclodextrin (γ-CD), heptakis (2,6-di-O-methyl)-β-cyclodextrin (DM-β-CD), sulfobutyl-β-cyclodextrin (SBE-β-CD), hydroxypropylmethylcellulose (HPMC), and egg albumin. In this study, two types of tablets were prepared; the coated tablet contained the complex of racemic salbutamol and cyclodextrin (γ-CD, DM-β-CD, and SBE-β-CD), and the uncoated tablet was composed of the drug with either HPMC or egg albumin. Subsequently, these formulations were evaluated for enantioselective release. The results revealed that the formulations containing either SBE-β-CD, HPMC, or egg albumin had no enantioselective release, while the formulation with DM-β-CD gave slightly different release of the two enantiomers at the end of the dissolution profile. The formulation containing γ-CD provided significant stereoselectivity throughout the dissolution profile. The release of the eutomer R-salbutamol was higher than that of the distomer S-salbutamol from the γ-CD tablet. In addition, the enantioselective interaction for the γ-CD inclusion complex was investigated by ¹H-NMR (nuclear magnetic resonance) spectroscopy and gave evidence to support the enantioselectivity obtained on dissolution.     

Preparation and Characterization of Albendazole β-Cyclodextrin Complexes

Albendazole (ABZ), mebendazole (MBZ), and ricobendazole (RBZ) are low-soluble anthelmintic benzimidazole carbamate drugs. To increase their aqueous solubility, three different types of β-cyclodextrins (CyDs): β-cyclodextrin (CD), hydroxypropyl-β-cyclodextrin (HPCD), and methyl-β-cyclodextrin (MCD) were used. Solubility depended on the type of CyDs. Increased solubility was obtained when the more substituted CyDs (HPCD or MCD) were used instead of nonsubstituted CD. Stability constants were calculated assuming a 1:1 stoichiometry. Calculated stability constant values depended on initial solubility of drug and pH of the medium. Solid ABZ complexes were prepared by coprecipitation and freeze-drying methods. These products were compared with physical mixtures of ABZ and CyDs. The characterization of these products was made by differential scanning calorimetry (DSC) and drug release studies. True inclusion complexes were obtained only by the freeze-drying method. Drug release studies showed that the freeze-dried inclusion complexes increased the solubility rate of ABZ, although a supersaturation effect was observed when drug release studies were performed in nonsink conditions. A bioavailability study on mice was done with a formulation of ABZ : HPCD complex and was compared to a conventional ABZ suspension. A significantly (p <. 05) shorter T_max of absorption was obtained by using the complex formulation. Greater and significant (p <. 05) differences for AUC and C_max were observed.     

Effects of Cyclodextrins and Phospholipids in Enhancing Dissolution of Indomethacin

Abstract

Inclusion complexes of indomethacin (IND) and β-cyclodextrins (β-CD) were prepared by the freeze drying methods. Solid dispersion of IND and Dimyristoylphosphatidylcholine (DMPC) was prepared as coprecipitate (CPPT) by the solvent method. These formulations were characterized by X-ray diffractometry and dissolution rate determinations. Dissolution of IND from β-CD inclusion complex was found to be 133 times faster than the corresponding pure IND, whereas it was about 4 times faster from a DMPC CPPT sample. Various derivatives of β-CDs showed variable rates of dissolution of IND. β-CD and most of the other derivatives showed almost instantaneous dissolution of IND at a molar ratio of 1:1 (IND:β-CD) except dimethyl-β-cyclodextrin (DMB) derivative, which showed a fairly constant release of IND over 90 minutes. DMB may, therefore, have the potential for use in the formulation of a constant-release preparation. X-ray diffraction spectra showed that indomethacin remained as amorphous state in CPPT or in inclusion complex. Thus, these formulations may have the potential to produce faster onset of action, reduced dosing and decreased GI irritation.     

Solubility and dissolution rate improvement of the inclusion complex of apigenin with 2-hydroxypropyl-β-cyclodextrin prepared using the liquid antisolvent precipitation and solvent removal combination methods

Apigenin (AP) has many pharmacological activities. AP has poor solubility in some solvents. AP is insoluble in water and slightly soluble in ethanol (1.93?mg/ml). It has limited application and exploitation. Therefore, the liquid antisolvent precipitation (LAP) method was applied to improve the solubility of AP in ethanol by changing its crystal form or producing ultra-fine particles. Then, the inclusion complex of AP with 2-Hydroxypropyl-β-cyclodextrin (HP-β-CD) is prepared using the solvent removal method. The effects of various experimental parameters on the solubility of AP in ethanol were investigated through the single factor design. Under the optimum conditions, the AP–ethanol solution of 6.19?mg/ml was obtained. The inclusion complex of AP with HP-β-CD was obtained by the solvent removal method. The load efficiency (LE) and drug encapsulation efficiency (EE) of the inclusion complex of AP with HP-β-CD were 13.98%±0.14% and 97.86%±1.07%, respectively. SEM, FTIR, ¹HNMR, XRD, DSC and TG were used to analyze the characteristics of the inclusion complex of AP with HP-β-CD. These results showed that the inclusion complex has significantly different characteristics with AP. In addition, the dissolution rate and solubility of the inclusion complex were approximately 15.24 and 68.7 times higher than AP in artificial gastric juice, and was separately 10.4 times and 40.05 times higher than AP in artificial intestinal juice. The bioavailability of inclusion complex increased 3.97 times compared with AP.     

Higher order equilibria and their effect on analyte migration behavior in capillary electrophoresis

This paper presents a quantitative investigation into the effect of analyte-additive interactions on analyte migration behavior in capillary electrophoresis (CE) when both 1:1 and 1:2 stoichiometries are present. Equations based on the individual capacity factors for each interaction are derived to account for the effect of both first- and second-order equilibria. The analyte migration behavior is described using these equations with a full account of how the microscopic equilibrium constants and microscopic mobilities are combined to give the macroscopic values. The binding isotherms of interactions with both 1:1 and 1:2 stoichiometries are compared with those of a 1:1 stoichiometry. 4,4'-Biphenol and 4-phenylphenol were chosen as analytes that undergo complexation with one and two hydroxypropyl-β-cyclodextrin (HP-β-CD) molecules; phenol was used as an analyte that interacts with only one HP-β-CD molecule. The process of calculating higher order equilibrium constants and complex mobilities from the binding isotherms is demonstrated. The effects of experimental conditions, such as the additive concentration range and the number of data points, on the error in the calculated constants and the ability of the equations to accurately describe the experimental data are discussed. A comparison of the linear transformations of the binding isotherm with respect to their ability to detect higher order equilibria is made, and the advantage of using the capacity factor in CE is illustrated.