Guar Gum-Alginate Gel Coated Etherified Fenugreek Seed Mucilage-Alginate Microhybrids as Stomach-Targeting Flurbiprofen-Cargos

Abstract

The present investigation aimed at developing core–shell structured partially etherified fenugreek seed mucilage (EFSM)-sodium alginate (SA) based microhybrids for controlled delivery of flurbiprofen (FLU) by combined gastroretentive bioadhesion and floating approaches. In this milieu, EFSM (degree of carboxymethyl substitution, 0.71) was firstly synthesized and analyzed through ¹H NMR and SEM studies. FLU-loaded EFSM-SA core hybrids were subsequently afforded by Ca²⁺-induced gelation protocol with and without incorporating low-density additives (such as, sunflower oil and calcium silicate) in the formulations. The core matrices were then coated by bioadhesive guar gum (GG)-SA gel membrane utilizing interfacial complexation technique. The developed microhybrids portrayed outstanding drug entrapping efficiency (DEE, 45–89%) and delayed drug eluting behaviour (Q_8h, 56–85%). These attributes were significantly influenced by various formulation variables like polymer-blend (EFSM:SA) ratios, low-density additive types and GG-SA coating inclusion. The drug dissolution profile of the core–shell structured microhybrids (F-7) obeyed zero-order kinetic model and its drug transport was driven by case-II mechanism. The formulation (F-7) also demonstrated excellent gastroretentive characteristics and biodegradability. The molar mass ($\overline{\mathrm{M}}$_c) between crosslinks of microhybrids (F-7) calculated utilizing Flory-Rehner equation was decreased with temperature. Furthermore, the microhybrids were characterized for drug-excipients compatibility, thermal behaviour, drug crystallinity and surface morphology. These novel composite matrices were thus evidenced to be appropriate for controlled intragastric delivery of FLU for inflammation and arthritis management.