The effects of three hydrophilic polymers, namely, carboxymethyl cellulose sodium (CMC-Na), polyvinyl alcohol (PVA) and poloxamer-188 (PXM-188) on the solubility and dissolution of diflunisal (DIF) in complexation with β-cyclodextrin (βCD) or hydroxypropyl β-cyclodextrin (HPβCD), were investigated. The kneading method was used at different drug to cyclodextrin weight ratios. Increases in solubility and drug release were observed with the DIF/βCD and DIF/HPβCD complexes. The addition of hydrophilic polymers at 2.5, 5.0 and 10.0% w/w markedly improved the complexation and solubilizing efficiency of βCD and HPβCD. Fourier-transform infrared (FTIR) showed that DIF was successfully included into the cyclodextrin cavity. Differential scanning calorimetry (DSC) and X-ray diffractometry (XRD) confirmed stronger drug amorphization and entrapment in the molecular cage of cyclodextrins. The addition of PVA, CMC-Na or PXM-188 reduced further the intensity of the DIF endothermic peak. Most of the sharp and intense peaks of DIF disappeared with the addition of hydrophilic polymers. In conclusion, PXM-188 at a weight ratio of 10.0% w/w was the best candidate in enhancing the solubility, stability and release of DIF.
Arthritic disease is one of the most common diseases in adults and a leading cause of joint degeneration. Dexibuprofen (DEX) is routinely used for the treatment of rheumatoid arthritis, acute postoperative pain, primary dysmenorrheal, and in lower back pain. However, it is poorly water soluble with compromised bioavailability, and hence has limited therapeutic activity. In order to overcome these issues, we studied the formulation and characterization of nanoemulsion based system i.e nanoemulgel of DEX. This study aimed to prepare topical nanoemulgel containing 2 % DEX and solubility-enhanced DEX via ternary inclusion complexation (DEX-SE-T) and to compare it with commercially available 5 % Ibuprofen gel as there is no topical formulation of DEX is available in the market currently. A pseudoternary phase diagram was constructed using the spontaneous water titration method. Blank and drug-loaded nanoemulgel were prepared using a high-speed homogenization method. All the formulations were evaluated in terms of particle size, pH, conductivity, viscosity, zeta potential, and ex vivo drug permeation. DEX loaded nanoemulgel yield enhanced in vitro skin permeation than the commercially available 5 % ibuprofen gel. The optimized nanoemulgel formulation (DEX-SE-T) was tested in in vivo anti-inflammatory models including cotton pellets-induced abdominal granuloma (chronic inflammation) and carrageenan-induced paw edema (acute inflammation). DEX-SE-T loaded nanoemulgel has improved in vivo anti-inflammatory activity as compared to ibuprofen gel. DEX-SE-T could be a promising option for effective topical treatment of inflammatory conditions.