Drug property improvement stabilization

Improvement of the properties of a drug may be achieved by the chemical modification of the parent drug. The preparation of an ester, salt, or other modification of the parent structure may be employed with parenteral drugs to increase stability, alter drug solubility, enhance depot action, avoid formulation... 

Gas chromatographic separation has not gained wide acceptance in spite of being quite sensitive and specific. This mode of separation is complicated by the need for derivatization of sulfonamide residues before gas chromatographic analysis. These drugs are subjected to derivatization via methylation with diazomethane (223, 224, 253, 254, 271), or double derivatization via methylation followed either by silylation with Ai-methyl-Ai-trimethylsilytrifluoroacetamide (261) or by acylation with A-methyl-bis(trifluoroacetamide) (256). This derivatization step is required not only to form the volatile derivatives of the sulfonamides but also to improve their chromatographic properties (thermal stability and decreased polarity). 

Both of these objectives are achievable provided the delivery (transport) properties of the drug are improved while maintaining its biological activity in vivo. In this context, the parent drug properties, such as lipid solubility, aqueous solubility, partition coefficient, and chemical and metabolic stability, are optimized, often in a balanced combination. 

The natural CyDs and their synthetic derivatives have successfully been applied to improve undesirable drug properties such as solubility, stability or bioavailability. In... 

The high proportion of counterionic condensation in PE-dmg aqueous dispersions determines many of the particular properties of these systems such as the effects of addition of electrolytes and non-electrolytes, the kinetic of drug release under different conditions, the raise of compatibihty of low solubility drugs, the improvement of chemical stability and the rheological behavior. 

Nanocarriers based on polymers have attracted much attention due to their advantages compared to other conventional materials. Polymeric materials offer major flexibility in the methods of synthesis a broad diversity in terms of nature, properties, and composition easy functionalization and the possibility to be stimuli responsive [14]. Nano-sized polymeric carriers have been extensively applied, because, in general, loaded nano-sized carriers can improve drug solubihty and stability in vivo, and can target a (hug to the tumor site protecting the healthy tissue. 

It is known that CDs form inclusion complexes with a variety of compounds, e.g. lipophilic drugs, modifying their properties. The inclusion of a drug can improve its solubility, stability and bioavailability, therefore CDs are very convenient drug carriers. 

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