Solubility, the phenomenon of dissolution of solute in solvent to give a homogenous system, is one of the important parameters to achieve desired concentration of drug in systemic circulation for desired (anticipated) pharmacological response. Low aqueous solubility is the major problem encountered with formulation development of new chemical entities as well as for the generic development. More than 40% NCEs (new chemical entities) developed in pharmaceutical industry are practically insoluble in water. Solubility is a major challenge for formulation scientist. Any drug to be absorbed must be present in the form of solution at the site of absorption. Various techniques are used for the enhancement of the solubility of poorly soluble drugs which include physical and chemical modifications of drug and other methods like particle size reduction, crystal engineering, salt formation, solid dispersion, use of surfactant, complexation, and so forth. Selection of solubility improving method depends on drug property, site of absorption, and required dosage form characteristics.

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Drug Solubility: Importance and Enhancement Techniques

Polysaccharides or polymeric carbohydrate molecules are long chains of monosaccharides that are linked by glycosidic bonds. The naturally based structural materials are widely applied in biomedical applications. This article covers four different types of polysaccharides (i.e., alginate, chitosan, hyaluronic acid, and dextran) and emphasizes their chemical modification, preparation approaches, preclinical studies, and clinical translations. Different cargo fabrication techniques are also presented in the third section. Recent progresses in preclinical applications are then discussed, including tissue engineering and treatment of diseases in both therapeutic and monitoring aspects. Finally, clinical translational studies with ongoing clinical trials are summarized and reviewed. The promise of new development in nanotechnology and polysaccharide chemistry helps clinical translation of polysaccharide-based drug delivery systems.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/advs.201700513

Polysaccharide-Based Controlled Release Systems for Therapeutics Delivery and Tissue Engineering: From Bench to Bedside.

Analytical techniques for characterization of cyclodextrin complexes in the solid state: A review.

Identification of cyclodextrin inclusion complex of chlorogenic acid and its antimicrobial activity

The present study aims to prepare carvedilol (CAR) nanosuspensions using the anti-solvent precipitation-ultrasonication technique to improve its dissolution rate and oral bioavailability. Alpha-tocopherol succinate (VES) was first used as a co-stabilizer to enhance the stability of the nanosuspensions. The effects of the process parameters on particle size of the nanosuspensions were investigated. The optimal values of the precipitation temperature, power inputs, and the time length of ultrasonication were selected as 10°C, 400 W, and 15 min, respectively. Response surface methodology based on central composite design was utilized to evaluate the formulation factors that affect the size of nanosuspensions, i.e., the concentration of CAR and VES in the organic solution, and the level of sodium dodecyl sulfate in the anti-solvent phase, respectively. The optimized formulation showed a mean size of 212 ± 12 nm and a zeta potential of -42 ± 3 mV. Scanning electron microscopy revealed that the nanosuspensions were flaky-shaped. Powder X-ray diffraction and differential scanning calorimetry analysis confirmed that the nanoparticles were in the amorphous state. Fourier transform infrared analysis demonstrated that the reaction between CAR and VES is probably due to hydrogen bonding. The nanosuspension was physically stable at 25°C for 1 week, which allows it to be further processing such as drying. The dissolution rate of the nanosuspensions was markedly enhanced by reducing the size. The in vivo test demonstrated that the C(max) and AUC(0-36) values of nanosuspensions were approximately 3.3- and 2.9-fold greater than that of the commercial tablets, respectively.

Fabrication of Carvedilol Nanosuspensions Through the Anti-Solvent Precipitation–Ultrasonication Method for the Improvement of Dissolution Rate and Oral Bioavailability

Xianhong Wen

Papers

Preparation and study the 1:2 inclusion complex of carvedilol with β-cyclodextrin

Crystal Structures of Six Salts from Nicotinamide and Organic Acids by Classical H-Bonds and Other Noncovalent Forces