Cloisite® 20A and polymer hydrogel as nano-vehicle for targeted and sustained release of Amitriptyline

A class of nanomaterials known as anionic and cationic clays has drawn a lot of interest as a potential medication delivery vehicle. Therefore, cloisite® 20A (C-20A), chitosan hydrogel (CH) and sodium alginate hydrogel (Alg) were used as a carrier for sustained release of amitriptyline drug (AMT) as oral osmotic drug delivery system. AMT was intercalated inside the interlayer space of C-20A as well as wrapped inside CH and Alg hydrogels and prepared AMT/C-20A, AMT/CH and AMT/Alg hybrids. The intercalation of AMT inside the layer of C-20A and hydrogels were confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The contents of intercalated AMT in the AMT/C-20A, AMT/CH and AMT/Alg was determined to be 10∼12%. The release of AMT from AMT/C-20A, AMT/CH and AMT/Alg were studied at a variable value of pH (1.2∼7.4). The dissolution of AMT from the AMT/C-20A, AMT/CH and AMT/Alg into the release medium was found to be a maximum (97 %, 60 % and 80 %) at pH 6.8 as the optimum pH for AMT release, and further kinetics of the drug release from the hybrids were explored. The results were fitted well to Freundlich diffusion relationship. The high release of the AMT from C-20A and CH hydrogel indicates that C-20A and CH hydrogel enables the intercalation of the AMT and allows them to be released into the target site. By comparing the release of AMT from C-20A and CH hydrogel, AMT release from C-20A was quite efficient and fast. Thus, to make the release of the intercalated AMT in more sustained manner, and consequently reduce frequency of AMT administration, AMT/C-20A was further wrapped inside CH (AMT/C-20A/CH) and Alg hydrogels (AMT/C-20A/Alg) and found the release of AMT drug in more sustainable manner and reduced the frequency of AMT administration.