title: Thiolated poly(aspartic acid) as potential in situ gelling, ocular mucoadhesive drug delivery system.
abstract: The ophthalmic formulations on the market suffer from poor bioavailability, and it would therefore be useful to design a new formulation which is able to prolong the residence time and reduce the administration frequency. Polymer matrices which exhibit strong mucoadhesion are promising platforms in ocular drug delivery from the aspect of improved bioavailability. In the present study, an in situ gelling, mucoadhesive drug delivery system was fabricated from thiolated poly(aspartic acid) (ThioPASP). The thiol groups of ThioPASP are able to form disulphide linkages with the mucin glycoproteins and prolong the residence time on the eye. The effects of the thiol groups on the structure, swelling behaviour and mucoadhesive character of the gel and on the drug release profile were determined. The gel structure was characterized by means of rheology. The ThioPASP gel was demonstrated by rheology, tensile test and 'wash away' measurements to display strong mucoadhesion. The drug release from the ThioPASP gel was studied on a vertical Franz diffusion cell: a burst release of sodium diclofenac occurred in the first hour, followed by sustained release of the encapsulated drug for up to 24h. The results proved the importance of the presence of the thiol groups and suggested that a ThioPASP formulation can be useful as an in situ gelling, ocular dosage form.
authors.affiliation: Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Szeged, Eötvös u. 6, H-6720 Szeged, Hungary.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Horvát
authors.affiliation: Soft Matters Group, Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, Budafoki út 8., H-1111 Budapest, Hungary.
authors.forename: Benjámin
authors.initials: B
authors.lastname: Gyarmati
authors.affiliation: Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Szeged, Eötvös u. 6, H-6720 Szeged, Hungary.
authors.forename: Szilvia
authors.initials: S
authors.lastname: Berkó
authors.affiliation: Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Szeged, Eötvös u. 6, H-6720 Szeged, Hungary.
authors.forename: Piroska
authors.initials: P
authors.lastname: Szabó-Révész
authors.affiliation: Soft Matters Group, Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, Budafoki út 8., H-1111 Budapest, Hungary.
authors.forename: Barnabás Áron
authors.initials: BÁ
authors.lastname: Szilágyi
authors.affiliation: Soft Matters Group, Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, Budafoki út 8., H-1111 Budapest, Hungary.
authors.forename: András
authors.initials: A
authors.lastname: Szilágyi
authors.affiliation: Department of Ophthalmology, Faculty of Medicine, University of Szeged, Korányi fasor 10-11, H-6720 Szeged, Hungary.
authors.forename: Judit
authors.initials: J
authors.lastname: Soós
authors.affiliation: Department of Drug Sciences, Faculty of Pharmacy, University of Pavia, viale Taramelli 12, 27100 Pavia, Italy.
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Sandri
authors.affiliation: Department of Drug Sciences, Faculty of Pharmacy, University of Pavia, viale Taramelli 12, 27100 Pavia, Italy.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Bonferoni
authors.affiliation: Department of Drug Sciences, Faculty of Pharmacy, University of Pavia, viale Taramelli 12, 27100 Pavia, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Rossi
authors.affiliation: Department of Drug Sciences, Faculty of Pharmacy, University of Pavia, viale Taramelli 12, 27100 Pavia, Italy.
authors.forename: Franca
authors.initials: F
authors.lastname: Ferrari
authors.affiliation: Department of Drug Sciences, Faculty of Pharmacy, University of Pavia, viale Taramelli 12, 27100 Pavia, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Caramella
authors.affiliation: Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Szeged, Eötvös u. 6, H-6720 Szeged, Hungary. Electronic address: csanyi@pharm.u-szeged.hu.
authors.forename: Erzsébet
authors.initials: E
authors.lastname: Csányi
authors.affiliation: Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Szeged, Eötvös u. 6, H-6720 Szeged, Hungary.
authors.forename: Mária
authors.initials: M
authors.lastname: Budai-Szűcs
mesh_terms: D000268:Adhesiveness; D060433:Administration, Ophthalmic; D016503:Drug Delivery Systems; D065546:Drug Liberation; D020100:Hydrogels / Q000737:chemistry; D009077:Mucins / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D012212:Rheology; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D020100:Hydrogels; D009077:Mucins; D010455:Peptides; D013438:Sulfhydryl Compounds; C017645:polyaspartate
keywords: Mucoadhesion; Ocular drug delivery system; Rheology; Sodium diclofenac; Tensile test; Thiolated polymer