Drug delivery investigations of quaternised poly(propylene imine) dendrimer using nimesulide as a model drug

•Quaternised poly(propylene imine) dendrimer of generation-3, QPPI (G3), is expected to serve as drug carrier for poorly soluble drugs like nimesulide, NMD.•QPPI (G3) forms complex with NMD which reflects in significant drug loading potential.•This complexation leads to increase the solubility and sustains the release of NMD under in vitro conditions.•QPPI (G3) has reduced the cytotoxicity in comparison with PPI (G3) dendrimer.•QPPI (G3) is a promising candidate in the design of polymeric drug delivery systems to enhance the bioavailability of the poorly soluble drugs. This study describes the demonstration of quaternized poly(propylene imine) dendrimer of generation-3, QPPI (G3) as a drug carrier for poorly soluble drug nimesulide (NMD, an anti-inflammatory drug). QPPI (G3) was prepared by treating the surface amine groups of poly(propylene imine) dendrimer with glycidyltrimethyl ammonium chloride and it was characterized with FTIR, 1H and 13C NMR and MALDI-TOF mass spectral techniques. The drug carrying potential of QPPI (G3) was assessed by analyzing drug solubility, in vitro release and cytotoxicity studies. The observed results reveal that the aqueous solubility of NMD has been dramatically increased in the presence of QPPI (G3) and also can sustain the release of NMD. It is further noticed that the complexation of NMD with QPPI (G3) is responsible for increased solubility and sustained release. This complexation was evidenced through NMR (1H & 2D) and UV–vis spectral techniques, DSC and DLS studies. Cytotoxicity study through MTT assay on Vero and HBL-100 cell lines reveal that this dendrimer increase the biocompatibility and the tolerance concentration of NMD in drug-dendrimer formulations. The observed results prove that the QPPI (G3) is one of the new promising candidate for effective delivery of NMD.