Solubility Enhancement of Antidiabetic Drugs Using a Co-Crystallization Approach

Co-crystallization of Hesperidin with different co-formers to enhance solubility, antioxidant and anti-inflammatory activities

Hesperidin (HSP) is a natural flavonoid glycoside with very low aqueous solubility and a slow dissolution rate, limiting its effectiveness. This study aims to address these issues by creating co-crystals of hesperidin with water-soluble small molecules (co-formers) such as L-arginine, glutathione, glycine, and nicotinamide. Using the solvent drop grinding method, we prepared three different molar ratios of hesperidin to co-formers (1:1, 1:3, and 1:5) and conducted in-vitro solubility and dissolution studies. The results demonstrated that the prepared co-crystals exhibited significantly enhanced solubility and dissolution rates compared to untreated hesperidin. Of particular note, the HSP co-crystals formula (HSP: L-arg 1:5) displayed approximately 4.5 times higher dissolution than pure hesperidin. Further analysis using FTIR, powder x-ray diffraction patterns, and DSC thermograms validated the formation of co-crystals between HSP and L-arginine. Additionally, co-crystallization with L-arginine improved the in vitro anti-inflammatory and antioxidant activities of hesperidin compared to the untreated drug. This study highlights the potential of using water-soluble small molecules (co-formers) through co-crystallization to enhance the solubility, dissolution, and biological activities of poorly water-soluble drugs. Furthermore, in vivo studies are crucial to validate these promising results.

A SWOT analysis of nano co-crystals in drug delivery: present outlook and future perspectives

The formulation of poorly soluble drugs is an intractable challenge in the field of drug design, development and delivery. This is particularly problematic for molecules that exhibit poor solubility in both organic and aqueous media. Usually, this is difficult to resolve using conventional formulation strategies and has resulted in many potential drug candidates not progressing beyond early stage development. Furthermore, some drug candidates are abandoned due to toxicity or have an undesirable biopharmaceutical profile. In many instances drug candidates do not exhibit desirable processing characteristics to be manufactured at scale. Nanocrystals and co-crystals, are progressive approaches in crystal engineering that can solve some of these limitations. While these techniques are relatively facile, they also require optimisation. Combining crystallography with nanoscience can yield nano co-crystals that feature the benefits of both fields, resulting in additive or synergistic effects to drug discovery and development. Nano co-crystals as drug delivery systems can potentially improve drug bioavailability and reduce the side-effects and pill burden of many drug candidates that require chronic dosing as part of treatment regimens. In addition, nano co-crystals are carrier-free colloidal drug delivery systems with particle sizes ranging between 100 and 1000 nm comprising a drug molecule, a co-former and a viable drug delivery strategy for poorly soluble drugs. They are simple to prepare and have broad applicability. In this article, the strengths, weaknesses, opportunities and threats to the use of nano co-crystals are reviewed and a concise incursion into the salient aspects of nano co-crystals is undertaken.

In Situ Co-Amorphization of Olanzapine in the Matrix and on the Coat of Pellets

In situ amorphization is a promising approach, considered in the present work, to enhance the solubility and dissolution rate of olanzapine, while minimizing the exposure of the amorphous material to the stress conditions applied during conventional processing. The production of pellets by extrusion/spheronization and the coating of inert beads were investigated as novel methods to promote the co-amorphization of olanzapine, a poorly water-soluble drug, and saccharin. Samples were characterized using differential scanning calorimetry, X-ray powder diffraction, Fourier-transform infrared spectroscopy and scanning electron microscopy, and dissolution and stability testing. The co-amorphous produced were compared with crystalline olanzapine, or physical mixture of olanzapine and saccharin. Results suggested that the addition of water to mixtures containing olanzapine and saccharin during the production of pellets, and the coating of inert beads, induced the in situ co-amorphization of these substances. The coating of inert beads enhanced the solubility and dissolution rate of olanzapine, especially when compared to pellets coated with the crystalline drug, but also with pellets containing the co-amorphous entity in the matrix of beads. Nine months stability tests (23 °C/60% RH) confirmed the preservation of the solid-state properties of the co-amorphous form on/in pellets. Overall, results highlighted the feasibility and benefits of in situ co-amorphization, either when the drug was entrapped in the pellets matrix, or preferentially applied directly on the surface of pellets.