Digoxin, dissolution rate

Drugs in Class II have low aqueous solubility (but high membrane permeability), and any factor affecting dissolution rate would be expected to have an impact on the absorption of such compounds. Factors that are noted in Fig. 11, such as fluid pH, volume and viscosity, and bile secretion (especially in response to fatty foods), might be expected to play a role in dissolution rate and thereby affect absorption. Compounds that fall into this class include carbamazepine, cyclosporin, digoxin, griseofulvin, and spironolactone. Food would be expected to exert a potentially significant affect on... 

Determination of ethinyloestradiol in tablets Determination of the dissolution rate of digoxin tablets... 

Particle size may play a major role in drug absorption. Dissolution rate of solid particles is proportional to surface area, and hence to particle fineness. Particle size reduction has been used to increase the absorption of a large number of poorly soluble drugs, such as bishydroxycoumarin, digoxin, griseofulvin, nitrofurantoin, and tolbutamide. 

When two substances form a molecular compound, it usually gives rise to a maximum in the phase diagram. An example of this is the quinine-phenobarbital sys-tem shown in Fig. 6. It is difficult to generalize the influence of complex formation on dissolution. A complex between digoxin and hydroquinone exhibited a high dissolution rate, whereas the insoluble complex... 

Spray-Dried Products. Spray drying is used to convert solutions, emulsions, or suspensions into powders. The applications in pharmaceutical technology are numerous. Raw materials are spray dried, for instance, to enhance the compressional properties of substances such as lactose and tricalcium phosphate, to distribute a minor component like digoxin more uniformly in a matrix, and to enhance their dissolution rate as described for digoxin in combination with a hydrophilic polymer. ... 

Fraser EJ, Leach RH, Poston JW, Bold AM, Culank LS, Lipede AB. Dissolution-rates and bioavailability of digoxin tablets. Lancet (1913) i, 1393. 

Marked increases in the dissolution rate of digitoxin and digoxin has been achieved by dispersing the drugs in solid poloxamer 188 (Pluronic F68) as a carrier [251] (see Fig. 6.34). Poloxamer 188, in concentrations equivalent to that in the digoxin co-precipitates studied, increased the solubility of the digoxin as shown in Table 6.29 in which results are compared with the effects of deoxycholic... 

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