title: Gellan-thioglycolic acid conjugate: synthesis, characterization and evaluation as mucoadhesive polymer.
abstract: Gellan-thioglycollic acid conjugate was synthesized with the objective to improve its mucoadhesive properties. Synthesis of conjugate was confirmed by -SH stretch in the Fourier-transform infrared spectra at 2571 cm(-1). It was found to contain 13.92 mM of thiol groups/g of the conjugate. Thiolation of gellan gum was found to slightly increase its degree of crystallinity and decrease its sensitivity to Ca(2+)-induced gelation. On screening of gellan-thioglycollic acid conjugate for ex-vivo ocular tolerance using hen's egg chorio-allantoic membrane test and for biocompatibility by resazurin assay on Vero-cells, it was found to be non-irritant and biocompatible. Metronidazole gels formulated using gellan thioglycollic acid conjugate as bioadhesive agent showed 1.82-fold higher mucoadhesive strength than the gels formulated using gellan gum. Further, the metronidazole gels containing gellan and gellan-thioglycollic conjugate released the drug following first-order and Higuchi's square-root release kinetics. In conclusion, gellan-thioglycollic acid conjugate is a promising bioadhesive excipient.
authors.affiliation: Drug Delivery Research Laboratory, Department of Pharmaceutical Sciences, Guru Jambheshwar University of Science and Technology, Hisar 125 001, India.
authors.forename: Shikha
authors.initials: S
authors.lastname: Yadav
authors.forename: Munish
authors.initials: M
authors.lastname: Ahuja
authors.forename: Ashok
authors.initials: A
authors.lastname: Kumar
authors.forename: Harmanmeet
authors.initials: H
authors.lastname: Kaur
mesh_terms: D000269:Adhesives / Q000138:chemical synthesis* / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000737:chemistry; D002470:Cell Survival / Q000187:drug effects; D002642:Chick Embryo; D002522:Chlorocebus aethiops; D049033:Chorioallantoic Membrane / Q000187:drug effects; D003460:Crystallization; D007700:Kinetics; D008795:Metronidazole / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D044367:Phase Transition; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013864:Thioglycolates / Q000737:chemistry*; D014709:Vero Cells
chemical_list: D000269:Adhesives; D011135:Polysaccharides, Bacterial; D013864:Thioglycolates; D008795:Metronidazole; C048288:gellan gum; C017487:2-mercaptoacetate; D002118:Calcium
keywords: Gellan; Mucoadhesive; Ocular tolerance; Thiomer; Vero cell