title: An electro-conductive fluid as a responsive implant for the controlled stimuli-release of diclofenac sodium.
abstract: The purpose of this study was to develop an electro-responsive co-polymeric (ERP) implantable gel from polyethylene glycol (PEG), sodium polystyrene sulphonate (NaPss), polyvinyl alcohol (PVA), and diethyl acetomidomalonate (DAA) for electro-liberation of the model drug diclofenac sodium. Various physicochemical and physicomechanical characterization tests were undertaken on the synthesized drug-free gel (ERP G1) and drug-loaded gel (ERP G2). The ability of the gel to release diclofenac sodium following electrical stimulation was evaluated using a galvanostat while Molecular Mechanics (MM) simulations were performed to elucidate the experimental mechanisms. A stable electro-active gel exhibiting superior cycling stability was produced with desirable rheological properties, rigidity (BHN = 35.4 N ± 0.33 N/mm2; resilience = 10.91 ± 0.11%), thermal properties (Tg≈ 70 °C; Tc≈ 200 °C) and homogeneous morphology. "ON-OFF" pursatile gradual drug release (37-94% from t30 min-t180min) kinetics was observed upon applying electric stimulation intermittently, indicating that drug release from the gel was electrically controlled. Overall, the galvanometric and MM evaluation ascertained the suitability of the PEG/NaPss/PVA ERP-Gel for application as a subcutaneously injectable drug delivery implant.
authors.affiliation: a Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand , Parktown , South Africa.
authors.forename: Divya
authors.initials: D
authors.lastname: Bijukumar
authors.affiliation: a Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand , Parktown , South Africa.
authors.forename: Yahya E
authors.initials: YE
authors.lastname: Choonara
authors.affiliation: a Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand , Parktown , South Africa.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Kumar
authors.affiliation: a Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand , Parktown , South Africa.
authors.forename: Lisa C
authors.initials: LC
authors.lastname: du Toit
authors.affiliation: a Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand , Parktown , South Africa.
authors.forename: Viness
authors.initials: V
authors.lastname: Pillay
mesh_terms: D003692:Delayed-Action Preparations / Q000008:administration & dosage / Q000737:chemistry*; D004008:Diclofenac / Q000008:administration & dosage / Q000737:chemistry*; D016503:Drug Delivery Systems / Q000379:methods; D065546:Drug Liberation; D005782:Gels / Q000008:administration & dosage / Q000737:chemistry; D008314:Malonates / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011137:Polystyrenes / Q000737:chemistry; D011142:Polyvinyl Alcohol / Q000737:chemistry
chemical_list: D003692:Delayed-Action Preparations; D005782:Gels; D008314:Malonates; D011108:Polymers; D011137:Polystyrenes; C030979:diethyl acetamidomalonic acid; D004008:Diclofenac; D011092:Polyethylene Glycols; C003321:polystyrene sulfonic acid; D011142:Polyvinyl Alcohol
keywords: Diclofenac sodium; electro-conductive fluid; molecular mechanics simulations; stimuli responsive implant; “ON–OFF” pulsatile drug release kinetics