pVp as an excipient is an important use of co-precipitants, some of the efficacy is good, on the contrary, its fatal disadvantage is that the solubility in water is very small, resulting in its bioavailability is greatly reduced, the use of some water-soluble substances and these co-precipitation, and then improve the solubility and dissolution rate, to reduce the dose, improve the effect of efficacy.
The main reason why pVp is used as a co-precipitant is that the dip group in the pVp molecule can be combined with the active hydrogen in the insoluble molecule, on the one hand, the relatively small molecule becomes an amorphous state into the pVp macromolecule, on the other hand, the hydrogen bonding does not change the property of pVp that is easily soluble in water, so the result is that the insoluble molecule is dispersed in the pVp macromolecule through hydrogen bonding, making it easily soluble, and some are insoluble with p Vp The changes in solubility after the formation of co-precipitates are as follows: the increase of solubility in the human body also correspondingly increases the bioavailability, such as the bioavailability of phenytoin and p Vp is increased by a factor after co-precipitation, and the solubility of the solubility after the co-precipitation of insoluble is related to the molecular weight of pVp and the amount of pVp.
In the case of the same amount (mass) of pVp, the solubility increase decreases in the order of PVP-K15 >PVP-K30 >PVP-K90", because the solubilization effect of PVP itself changes in the order of PVP-K15> PVP-K30> PVP-K90, and in general, pVp-K15 is used more.
