An Investigation of Nifedipine Miscibility in Solid Dispersions Using Raman Spectroscopy

Abstract

Raman spectroscopy was shown to be a useful technique in classifying miscibility levels based on the hydrophobic interaction between the drug and the polymer. Different drug loadings showed varying degrees of drug-polymer interaction, and hence variable solid state stability of the solid dispersion.

Release Problems for Nifedipine in the Presence of Soluplus

“…This result agrees with what previously reported [12] . Also the ester carbonyl stretching peak for nifedipine was observed to shift, but, since also the carbonyl band of the vinilcaprolactam and vinyl acetate parts of soluplus are found in the same range, this fact prevents the precision of the shift measurement.…”

“…The miscibility limit of nifedipine/soluplus co-precipitates was reported to be 30% w/w drug loading, using different preparation methods (freeze drying, melting and solvent evaporation) [12] . These values agree with what predicted by the Hildebrand's solubility parameters: the carriers used to prepare co-precipitates and nifedipine display Δδ values well below the critical limit [21,22] (Table 2).…”

“…Most of papers dealing with nifedipine co-precipitate concern a variety of carriers, such as phosphatidylcholine [2] , mannitol [3] , solutol [4] , PEG [5] , poloxamer [6] , sodium starch glycollate, croscarmellose sodium, eudragit E-100 [7] , Gelucire 44/14 [8] , HPMC [9] , Pluronic F68 and Gelucire 50/13 [10] in the form of solid or surface dispersions and co-precipitates [12] . Few examples can be found for nifedipine tested with soluplus, a new attractive carrier [12][13][14][15] to prepare co-precipitate of drug by hot-melt extrusion [16] .…”

“…Few examples can be found for nifedipine tested with soluplus, a new attractive carrier [12][13][14][15] to prepare co-precipitate of drug by hot-melt extrusion [16] . It represents a hydrophilic non-ionic multipurpose carrier for its ability to act as polymer matrix former suitable for co-precipitates; and is considered as a member of the fourth generation of co-precipitate carriers [17] .…”

“…In the case of the association nifedipine/soluplus literature has been mainly concerned with the study of interaction between the drug and the polymer, the miscibility limits, the effects of the preparing techniques and aging on dissolution behavior [12][13][14][15] . The original aim of our research was to compare a range of hydrophilic carriers, including soluplus, such as Gelucires, PEGs and Lutrols, in the nifedipine release improvement from co-precipitates.…”