Cyclodextrins and Drug Membrane Permeation: Thermodynamic Considerations.

Cyclodextrins are hydrophilic oligosaccharides that can increase aqueous solubility of lipophilic drugs through formation of water-soluble drug/cyclodextrin complexes. Although the complexes are hydrophilic, and as such do not permeate biological membranes, the complexes are known to enhance drug permeation through lipophilic membranes and improve drug bioavailability after, for example, oral administration. However, it is not clear how cyclodextrins enhance the permeation.

Preformulation studies of dovitinib free base: Solubility, lipophilicity and stability.

Dovitinib has been investigated as an anti-tumor drug due to its ability to inhibit multiple receptor tyrosine kinases. Dovitinib free base has a poor water solubility leading to poor absorption. Salts and lipid-based formulations have been used to improve drug availability.

Effect of Soluplus on γ-cyclodextrin solubilization of irbesartan and candesartan and their nanoaggregates formation.

The poor aqueous solubility of irbesartan (IRB) and candesartan cilexetil (CAC) may hamper their bioavailability when orally or topically administered. Among several attempts, the promising nanoaggregate formation by γ-cyclodextrin (γCD) complexation of drugs in aqueous solution with or without water-soluble polymers was investigated. According to phase solubility studies, Soluplus® showed the highest complexation efficiency (CE) of drug/γCD complexes among the polymers tested.

Topical drug delivery to the posterior segment of the eye: Thermodynamic considerations.

Almost all studies on non-invasive topical drug delivery to the eye have emphasized the importance of biological barriers, static membrane barriers such as the cornea and the conjunctiva/sclera and dynamic barriers such as the lacrimal drainage. Hardly any have discussed the importance of the thermodynamic activity of the permeating drug molecules. Most drugs permeate from the eye surface into the eye by passive diffusion where, according to Fick's first law, the drug concentration gradient over the various permeation barriers (e.

Effect of porcine pancreatic α-amylase on dexamethasone release from aqueous solution containing natural γ-cyclodextrin.

Dexamethasone release from natural γ-cyclodextrin (γCD) complexes was investigated in presence of porcine pancreatic α-amylase (PPA). The phase-solubility of dexamethasone in aqueous γCD solutions was determined, PPA degradation of γCD was investigated, and permeation studies were performed in simulated tear fluid. The phase-solubility profile was of B type and the stability constant (K) of the dexamethasone/γCD complex determined from the initial linear section of the profile was relatively high or 12887 M.