Solid dispersions with poloxamer

The formation of peroxides and formaldehyde in the high-purity polyoxyethylene surfactants in toiletries has been shown to lead to contact dermatitis [31], Peroxides in hydrogenated castor oil can cause autoxidation of miconazole [32], Oxidative decomposition of the polyoxyethylene chains occurs at elevated temperature, leading to the formation of ethylene glycol, which may then be oxidized to formaldehyde. When polyethylene glycol and poloxamer were used to prepare solid dispersions of bendroflumethiazide, a potent, lipophilic diuretic drug, the drug reacted with the formaldehyde to produce hydroflumethiazide [33],... 

The XRPD patterns of pure tadalafil, poloxamer 407 and solid dispersions were recorded using a Philips Analytic X-Ray PW3710 (Philips, The Netherlands) diffractometer with tube anode Cu over the 5-70° /20 interval at a scanning speed of 2°mm . The generator tension (voltage) and generator current were kept at 40 kV and 30 mA, respectively. 

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... 

This short chapter deals primarily with the effect of surfactants on the properties of suspensions. Suspensions can be prepared without surfactants, there being an increasing use of polymers for stabilizing dispersions of solids in liquids. We will restrict discussion here to the effects of conventional surface-active agents but will deal also with the use of surface-active polymers such as the poloxamers, as these bridge the gap between two very large subjects. The emphasis of the chapter is towards pharmaceutical suspensions. 

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