Abstract:
Fundamental research on bio-sourced eco-polymers is gaining global interest due to its sustainability, an advantage accepted both in academia and industrial research settings.
Malaysia offers rich natural biodiversity, which gives significant opportunities for the application of bio-products and by-products in the medical, biodiesel and pharmaceutical industries. One such bio-product is Ceiba pentandra gum (CPG), a natural product derived from the plant source. CPG exhibits physicochemical characteristics such as conjugation with oppositely charged polyelectrolytes to form polyelectrolytes complexes (PECs). The ability to form PECs provides an opportunity for CPG to be utilised as a potential pharmaceutical excipient in the preparation of controlled-release [CR] dosage forms (Dosage forms that release specified amounts over a stipulated period into the body). Based on our literature search, there has not been any research carried out to investigate the application of CPG as a CR polymer.
This research project was aimed at collecting fundamental physicochemical data on CPG, investigate and compare its ability to form PECs with chitosan (CHI), an anionic
and polyvinylpyrrolidone (PVP), a neutral polymer. The physicochemical
properties of CPG, its PECs formed with CHI and PVP were characterised using a range of fundamental techniques such as pH, conductivity, scanning electromagnetic microscopy, Fourier transform-infrared spectroscopy, powder X-ray diffraction and differential scanning
calorimetric (DSC). The ratios of CPG and the polyelectrolytes were optimised to obtain PECs with highest yields using the Design of Experiment (DoE) method employing Response Surface Design concept in the Design Expert 7.0 Database. The optimised PECs were then used to formulate metoprolol succinate CR tablets.
The evidence of PECs formation is very conclusive in the DSC study, whereas it was not the case in other studies. The Box Behnken experimental design was used for the optimisation of higher yield of PECs. This resulted in an increased yield of CPG:CHI in the concentration range of 3.11% to 1.04%, within the ratio of 4.86: 1.05. The increased yield
was also observed with CPG:PVP in the concentration of 5.03% to 1.12%, within the ratio of 8.45: 1.08. To investigate the drug release retarding efficiency of the CHI and PVP PECs, they were formulated in metoprolol CR tablets. The various tablet formulations met all the in-process standards for tablet preparation. The efficiency of the PECs to retard the drug release was investigated in simulated gastric fluid (SGF) as well as pH 6.8. The release profile of metoprolol at pH 6.8 from the CR tablets containing either CHI or PVP PEC met the dissolution rate standards as stated in United States Pharmacopoeia (USP). However, in the SGF medium, the CHI PEC performed better than PVP PEC in retarding the drug release as per USP dissolution rate standards. In a nutshell, the obtained results provided a platform to use CPG as a CR polymer in the development of once-daily tablet formulation.
