title: Chitosan citrate as multifunctional polymer for vaginal delivery. Evaluation of penetration enhancement and peptidase inhibition properties.
abstract: In the present work the employment of chitosan citrate (Chs citrate) as multifunctional polymer in vaginal applications was evaluated. Potential properties of penetration enhancement and protease inhibition could be expected because of the capability of citrate to bind divalent cations such as calcium, that is involved in the regulation of gap and tight junctions, and zinc, that is essential co-factor for some proteases. A comparison was performed with chitosan HCl (Chs HCl). Ex vivo drug permeation experiments were performed on pig vaginal mucosa, by application of 3.0% (w/w) chitosan gels. Acyclovir (5.0%, w/w) and ciprofloxacin HCl (0.3%, w/w) were used as low molecular weight model drugs. Fluorescein isothiocyanate dextran MW 4400 (FD4) was used as hydrophilic high molecular weight fluorescent probe (0.2%, w/w). In the case of low MW drugs the amount penetrated into pig vaginal mucosa was measured by extraction from tissue slices and HPLC detection. From the samples maintained in contact with FD4, slices were cut perpendicularly to the surface and observed by means of confocal laser scanning microscopy (CLSM). FD4 permeation was also measured in in-vitro cell culture model (Caco-2). The penetration enhancing capacity of Chs citrate was comparable to that of Chs HCl. Both Chs citrate and Chs HCl were tested for the inhibition of the proteolytic enzymes carboxypeptidase A and leucine aminopeptidase. In both cases Chs citrate showed a significantly higher inhibition of enzymatic activity with respect to Chs HCl.
authors.affiliation: Department of Pharmaceutical Technology, School of Pharmacy, Vle Taramelli 12, 27100 Pavia, Italy. cbonferoni@unipv.it <cbonferoni@unipv.it>
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Bonferoni
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Sandri
authors.forename: Silvia
authors.initials: S
authors.lastname: Rossi
authors.forename: Franca
authors.initials: F
authors.lastname: Ferrari
authors.forename: Sara
authors.initials: S
authors.lastname: Gibin
authors.forename: Carla
authors.initials: C
authors.lastname: Caramella
mesh_terms: D000212:Acyclovir / Q000008:administration & dosage / Q000493:pharmacokinetics; D000277:Adjuvants, Pharmaceutic / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D000282:Administration, Intravaginal; D000818:Animals; D001682:Biological Availability; D018938:Caco-2 Cells; D043422:Carboxypeptidases A / Q000037:antagonists & inhibitors / Q000737:chemistry; D002470:Cell Survival / Q000187:drug effects; D048271:Chitosan / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D002939:Ciprofloxacin / Q000008:administration & dosage / Q000493:pharmacokinetics; D003911:Dextrans / Q000008:administration & dosage / Q000493:pharmacokinetics; D016650:Fluorescein-5-isothiocyanate / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects; D007931:Leucyl Aminopeptidase / Q000037:antagonists & inhibitors / Q000737:chemistry; D009092:Mucous Membrane / Q000187:drug effects* / Q000378:metabolism; D011480:Protease Inhibitors / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D034421:Sus scrofa; D014622:Vaginal Creams, Foams, and Jellies / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D014783:Viscosity
chemical_list: D000277:Adjuvants, Pharmaceutic; D003911:Dextrans; D011480:Protease Inhibitors; D014622:Vaginal Creams, Foams, and Jellies; C408130:chitosan citrate; C015219:fluorescein isothiocyanate dextran; D002939:Ciprofloxacin; D048271:Chitosan; D007931:Leucyl Aminopeptidase; D043422:Carboxypeptidases A; D016650:Fluorescein-5-isothiocyanate; D000212:Acyclovir