Effect of PVP K30 and/or L-arginine on stability constant of etoricoxib-HPbetaCD inclusion complex: preparation and characterization of etoricoxib-HPbetaCD binary system

Cyclodextrin Multicomponent Complexes: Pharmaceutical Applications

Cyclodextrins (CDs) are naturally available water-soluble cyclic oligosaccharides widely used as carriers in the pharmaceutical industry for their ability to modulate several properties of drugs through the formation of drug-CD complexes. The addition of an auxiliary substance when forming multicomponent complexes is an adequate strategy to enhance complexation efficiency and to facilitate the therapeutic applicability of different drugs. This review discusses multicomponent complexation using amino acids; organic acids and bases; and water-soluble polymers as auxiliary excipients. Special attention is given to improved properties by including information on the solubility, dissolution, permeation, stability and bioavailability of several relevant drugs. In addition, the use of multicomponent CD complexes to enhance therapeutic drug effects is summarized.

Application of the Box-Behnken design for the production of soluble curcumin: Skimmed milk powder inclusion complex for improving the treatment of colorectal cancer

The main objective of this study was to develop a soluble product of the practically insoluble curcumin (CMN) to treat colorectal cancer more effectively than with pure CMN. To improve the solubility of CMN, various hydrophilic carriers of skimmed milk powder (SMP), polyvinylpyrrolidone (PVP), and mannitol (MNT) were utilized to prepare solid dispersion (SD) binary complexes. The prepared complexes were characterized in terms of their aqueous solubility and in vitro drug release and analyzed by Fourier transform infrared spectrophotometry, powder X-ray diffractometry, scanning electron microscopy, dynamic light scattering, and the novel dyeing test. Based on this characterization, the best SD complex was optimized using the Box-Behnken design (RSM-BBD). These results showed that the solubility of CMN was greatly improved in combination with SMP. The SD of CMN with SMP produced significantly improved solubility (0.646 ± 0.024 mg/ml) and dissolution (54.94 ± 3.21% at 5 min). Further, solid-state characterization revealed that the complex exhibited intermolecular inclusion of the drug and carrier. Also, the complex did not undergo any chemical modification owing to its amorphous form, and the novel dye test showed better coloring impact, indicating the solubility of CMN. The in vitro cytotoxicity of the complex showed that 50% inhibition (IC50) of SW480 and Caco-2 cells was achieved at a considerably lower concentration than that of pure CMN. Flow cytometry analysis confirmed that the cell cycle arrest was at G2/M phase (43.26% and 65.14%), and DNA fragmentation analysis investigation confirmed that the complex induced more DNA damage during apoptosis.

Inclusion complexes of cefuroxime axetil with β-cyclodextrin: Physicochemical characterization, molecular modeling and effect of l-arginine on complexation

The inclusion complexes of poorly water-soluble cephalosporin, cefuroxime axetil (CFA), were prepared with β-cyclodextrin (βCD) with or without addition of l-arginine (ARG) to improve its physicochemical properties. We also investigated the effect of ARG on complexation efficiency (CE) of βCD towards CFA in an aqueous medium through phase solubility behaviour according to Higuchi and Connors. Although phase solubility studies showed A_L (linear) type of solubility curve in presence and absence of ARG, the CE and association constant (Ks) of βCD towards CFA were significantly promoted in presence of ARG, justifying its use as a ternary component. The solid systems of CFA with βCD were obtained by spray drying technique with or without incorporation of ARG and characterized by differential scanning calorimetry (DSC), X-ray powder diffractometry (XRPD), scanning electron microscopy (SEM), and saturation solubility and dissolution studies. The molecular modeling studies provided a better insight into geometry and inclusion mode of CFA inside βCD cavity. The solubility and dissolution rate of CFA were significantly improved upon complexation with βCD as compared to CFA alone. However, ternary system incorporated with ARG performed better than binary system in physicochemical evaluation. In conclusion, ARG could be exploited as a ternary component to improve the physicochemical properties of CFA via βCD complexation.

Solid dispersion of prednisolone: solid state characterization and improvement of dissolution profile

BACKGROUND

Dissolution testing is an important test for judging the effectiveness of a pharmaceutical dosage form. Many drugs create adverse effect because of insufficient solubility at the physiological pH. This study is aimed to improve the dissolution properties of prednisolone (PRD) that falls under the category of class II biopharmaceutics system.

METHODS

In this study, preparation of solid dispersions with various water-soluble carriers was studied to improve the dissolution of PRD. To obtain the optimized formulation, solid dispersions were prepared employing different methods using different carriers with various drug:carrier ratios. Their dissolution behaviors were also compared. Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction, and thermal analysis were studied to characterize the prepared solid dispersion.

RESULTS

PRD formed stable complexes with carriers as indicated by the stability constants (K(a)) of 9.5-597.2 M(-1). The results indicated that in vitro dissolution rate of PRD was remarkably improved in the solid dispersion of the drug compared with physical mixture and drug alone. This can be attributed to improved wettability, dispersibility, decrease in crystallinity, and increase in amorphous fraction of the drug. The results obtained from Fourier transform infrared spectroscopy and powder X-ray diffraction showed good evidence of drug-carrier interaction while using carriers such as hydroxypropyl-β-cyclodextrin (HP-βCD) and polyethylene glycol (PEG). Crystallinity of the drug was reduced in the solid dispersions prepared with hydroxypropyl-β-cyclodextrin, polyvinylpyrrolidone-co-vinyl acetate 64, and PEG as revealed from the differential scanning calorimetry thermograms.

CONCLUSION

The results suggested that the solid dispersion with selected excipients is a powerful tool to accelerate the dissolution of poorly water-soluble drugs.

The role of L-arginine in inclusion complexes of omeprazole with cyclodextrins

In this study, we investigate how the effect of L-arginine (ARG) and cyclodextrins upon omeprazole (OME) stability and solubility. The effect of the presence of ARG on the apparent stability constants (K(1:1)) of the inclusion complexes formed between OME and each cyclodextrin, beta-cyclodextrin (betaCD), and methyl-beta-cyclodextrin (MbetaCD) is studied by phase solubility diagrams and nuclear magnetic resonance (NMR) spectroscopy. The interaction of OME with those cyclodextrins, in the presence of ARG, is characterized using NMR spectroscopy and molecular dynamics simulations. ARG significantly increases the drug solubility and complex stability, in comparison to inclusion complexes formed in its absence. The effect is more pronounced for the OME:betaCD complex. ARG also contributes to a larger stability of OME when free in aqueous solution. The combination of ARG with cyclodextrins can represent an important tool to develop stable drug formulations.