Synthesis and Characterization of β-Cyclodextrin/poly(1-naphthylamine) Inclusion Complex and In-Vitro Release Studies of Metformin Hydrochloride

The present preliminary study reports the synthesis of β-cyclodextrin/poly(1-naphthylamine) (PNA) inclusion complexes at varying concentrations of 1-naphthylamine as monomer. The synthesized complexes were investigated for their spectral and morphological characteristics. IR studies confirmed that with the increase the loading of PNA, the hydrogen bonding interaction between NH of PNA and OH of β-cyclodextrin increased which was corroborated by the increase in the peak intensity corresponding to the OH stretching vibration of pristine β-cyclodextrin. UV studies confirmed the presence of higher number of quinoid units in PNA and tits interaction with β-cyclodextrin upon higher loading. The occurrence of phase transition during complex formation was confirmed by XRD analysis. Morphological studies highlighted the core–shell like morphology of the complexes. Metformin hydrochloride (MET-HCl) was chosen as a model drug to study the in-vitro drug release characteristics of these inclusion complexes. The validity of kinetic models for the adsorption of MET-HCl was studied using pseudo-first order model, pseudo-second order model, Elovich kinetic model and Intra-Particle Diffusion kinetic model and it was found that highest correlation coefficient was shown by pseudo-second-order model as well as by Elovich kinetic model. Hence the drug adsorption predominantly followed the pseudo-second order kinetics model. The drug release was investigated at gastric fluid (pH 1.2) and intestinal fluid (pH value 7.4) for a period of 1 h. The model with the highest correlation coefficient was confirmed to be of zero order and the value of n at gastrointestinal as well as intestinal fluids was calculated to be 1.2781 and 1.3262 respectively indicating super case-II transport mechanism.