Sertaconazole/hydroxypropyl-β-cyclodextrin complexation: Isothermal titration calorimetry and solubility approaches

Biomimetic Systems Involving Macrophages and Their Potential for Targeted Drug Delivery

The concept of targeted drug delivery can be described in terms of the drug systems' ability to mimic the biological objects' property to localize to target cells or tissues. For example, drug delivery systems based on red blood cells or mimicking some of their useful features, such as long circulation in stealth mode, have been known for decades. On the contrary, therapeutic strategies based on macrophages have gained very limited attention until recently. Here, we review two biomimetic strategies associated with macrophages that can be used to develop new therapeutic modalities: first, the mimicry of certain types of macrophages (i.e., the use of macrophages, including tumor-associated or macrophage-derived particles as a carrier for the targeted delivery of therapeutic agents); second, the mimicry of ligands, naturally absorbed by macrophages (i.e., the use of therapeutic agents specifically targeted at macrophages). We discuss the potential applications of biomimetic systems involving macrophages for new advancements in the treatment of infections, inflammatory diseases, and cancer.

Could nanovesicles containing a penetration enhancer clinically improve the therapeutic outcome in skin fungal diseases?

Aim: To study whether the formulation of an antifungal drug in nanovesicular form containing skin penetration enhancer would clinically modulate its therapeutic effectiveness. Materials & methods: Nanovesicles containing different skin penetration enhancers ‘PEVs’ were prepared and loaded with sertaconazole. Penetration-enhancer vesicles were characterized for entrapment efficiency, particle size, zeta potential, elasticity, viscosity, morphology and ex vivo skin deposition. Selected formulae were preliminary tested for clinical efficacy on patients suffering from tinea corporis and tinea versicolor. Results & conclusion: The nanosize of the vesicles, their content of penetration enhancer and their deformable nature are three cornerstones positively influencing the therapeutic outcome of topical antifungal therapy, and hence, can be considered a promising treatment modality for skin fungal diseases.

Clotrimazole-cyclodextrin based approach for the management and treatment of Candidiasis - A formulation and chemistry-based evaluation

Clotrimazole (CT) is a poorly soluble antifungal drug that is most commonly employed as a topical treatment in the management of vaginal candidiasis. The present work focuses on a formulation approach to enhance the solubility of CT using cyclodextrin (CD) complexation. A CT-CD complex was prepared by a co-precipitation method. Various characterization techniques such as differential scanning calorimetry, infrared (IR) and X-ray spectroscopy, scanning electron microscopy and nuclear magnetic resonance (NMR) spectroscopy were performed to evaluate the complex formation and to understand the interactions between CT and CD. Computational molecular modeling was performed using the Schrödinger suite and Gaussian 09 program to understand structural conformations of the complex. The phase solubility curve followed an AL-type curve, indicating formation of a 1:1 complex. Molecular docking studies supported the data obtained through NMR and IR studies. Enthalpy changes confirmed that complexation was an exothermic and enthalpically favorable phenomenon. The CT-CD complexes were formulated in a gel and evaluated for release and antifungal activity. The in vitro release studies performed using gels demonstrated a sustained release of CT from the CT-CD complex with the complex exhibiting improved release relative to the un-complexed CT. Complexed CT-CD exhibited better fungistatic activity toward different Candida species than un-complexed CT.

Complexation and Chiral Drug Recognition of an Amphiphilic Phenothiazine Derivative with β‐Cyclodextrin

Promethazine hydrochloride (PTZ) is an amphiphilic drug derived from the phenothiazine structure that possesses a charged aliphatic chain with a chiral carbon. In the presence of beta-cyclodextrin (beta-CD), this drug undergoes significant changes of its photophysical properties in aqueous solution. Fluorescence spectroscopy measurements show the formation of a 1:1 stoichiometry complex with quantum yield lower than that of the pure PTZ, and two fluorescence lifetimes, which can be assigned to the free and complexed forms of the drug. In addition, (1)H NMR spectra, and 2D rotating-frame Overhauser enhancement spectroscopy (ROESY) were used to characterize the drug and the complex, and to determine the effects of the complexation on the aggregation. For the drug binary system, a noncooperative association process is observed, and in the presence of macrocycle, the chemical shifts reveal a chiral resolution of the drug enantiomers, with different stability constants of the complexes. beta-CD modifies the aggregation of PTZ in an extension that confirms the formation of a 1:1 complex. ROE enhancements and molecular modeling strategies show the most likely structure of the complex in solution, in which one of the phenyl rings is buried into the CD cavity, with a slight inclusion of the aliphatic part.