title: Thiomers and their potential applications in drug delivery.
abstract: Thiomers are the product of the immobilization of sulfhydryl-bearing ligands onto the polymer backbone of a conventional polymer, which results in a significant improvement in mucoadhesion; in situ gelation and efflux inhibition compare with unchanged polymers. Because of thiol groups, thiomers have more reactivity and enhanced protection against oxidation. Since the late 1990s, extensive work has been conducted on these promising polymeric excipients in the pharmaceutical field. Areas covered: This review covers thiomers, their classification and their different properties. Various techniques for the synthesis, purification and characterization of thiomers are described in detail. This review also encompasses their various properties such as mucoadhesion, permeation enhancement, in situ gelation and efflux inhibition, as well as different formulations based on thiomers. In addition to the use of thiomers as multifunctional excipients, this review also encompasses their use as drugs. Expert opinion: The synthesis is realized by linkage of sulfhydryl-bearing ligands but reported methods give low yields. Higher degrees of modification are not necessary and would probably lead to extreme changes in properties. Nevertheless, an accurate characterization of the final product is important. The scale-up procedure for industrial manufacturing has been adapted to produce GMP materials; Lacrimera® eye drops have already entered the European market.
authors.affiliation: a Department of Pharmacy , Quaid-e-Azam University , Islamabad , Pakistan.
authors.forename: Kifayat Ullah
authors.initials: KU
authors.lastname: Shah
authors.affiliation: b Department of Pharmaceutics, Faculty of Pharmacy , Gomal University , D.I.Khan , Pakistan.|c EA3452/CITHEFOR, Faculté de Pharmacie , Université de Lorraine , Nancy , France.
authors.forename: Shefaat Ullah
authors.initials: SU
authors.lastname: Shah
authors.affiliation: a Department of Pharmacy , Quaid-e-Azam University , Islamabad , Pakistan.
authors.forename: Naz
authors.initials: N
authors.lastname: Dilawar
authors.affiliation: a Department of Pharmacy , Quaid-e-Azam University , Islamabad , Pakistan.
authors.forename: Gul Majid
authors.initials: GM
authors.lastname: Khan
authors.affiliation: c EA3452/CITHEFOR, Faculté de Pharmacie , Université de Lorraine , Nancy , France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Gibaud
mesh_terms: D002626:Chemistry, Pharmaceutical; D016503:Drug Delivery Systems; D005079:Excipients / Q000737:chemistry; D008024:Ligands; D004364:Pharmaceutical Preparations / Q000008:administration & dosage; D011108:Polymers / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D005079:Excipients; D008024:Ligands; D004364:Pharmaceutical Preparations; D011108:Polymers; D013438:Sulfhydryl Compounds
keywords: Mucoadhesion; S-nitrosothiomers; oral delivery; preactivated thiomers; thiomers