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Class III – low permeability, high solubility . Example: cimetidine; The absorption is limited by the permeation rate but the drug is solvated very fast. If the formulation does not change the permeability or gastro-intestinal duration time, then class I criteria can be applied. Class IV – low permeability, low solubility . Example: bifonazole
The tables below provides information on the variation of solubility of different substances (mostly inorganic compounds) in water with temperature, at one atmosphere pressure. Units of solubility are given in grams of substance per 100 millilitres of water (g/100 ml), unless shown otherwise. The substances are listed in alphabetical order.
Cosolvents improve solubility between non-miscible phases, as demonstrated by a solute dissolved in organic solvent but insoluble in water (left). A cosolvent miscible in both phases and able to dissolve the solute is added to form a homogeneous solution of water, organic solvent, and compound (right).
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
Solubility in water can be estimated from the number of hydrogen bond donors vs. alkyl sidechains in the molecule. Low water solubility translates to slow absorption and action. Too many hydrogen bond donors, on the other hand, lead to low fat solubility, so that the drug cannot penetrate the cell membrane to reach the inside of the cell.
The overall incidence of adverse drug reactions to sulfa antibiotics is approximately 3%, close to penicillin; [3] hence medications containing sulfonamides are prescribed carefully. Sulfonamide drugs were the first broadly effective antibacterials to be used systemically, and paved the way for the antibiotic revolution in medicine.
Penetration enhancers improve the ability of the drug to permeate the mucosa for transmucosal delivery or penetrate into the layers of the epithelium for mucosal delivery. Enzyme inhibitors partake in the protection of the drug from mucosal enzyme degradation, and solubility modifiers increase the solubility of drugs that are poorly absorbed. [7]
Many drugs have more than one name and, therefore, the same drug may be listed more than once. Brand names and generic names are differentiated by capitalizing brand names. See also the list of the top 100 bestselling branded drugs, ranked by sales. Abbreviations are used in the list as follows: INN = International Nonproprietary Name