Topical Nanoparticulate Formulation of Drugs for Ocular Keratitis

The primary objective of this project is to develop drug-loaded polymeric nanoparticles suspended in a biocompatible gel for topical delivery of therapeutic agents commonly employed in the treatment of ocular viral/bacterial keratitis. PART 1: Poly(D,L-lactic-co-glycolic acid) (PLGA) nanoparticles (NP) of dipeptide monoester prodrugs of ganciclovir (GCV) including L-Val-L-Val-GCV (LLGCV), L-Val-D-Val-GCV (LDGCV), D-Val-L-Val-GCV (DLGCV) were formulated and dispersed in thermosensitive PLGA-PEG-PLGA polymer gel for the treatment of herpes simplex virus type 1 (HSV-1) induced viral corneal keratitis. NP containing prodrugs of GCV were prepared by a doubleemulsion solvent evaporation technique using various PLGA polymers with different drug/polymer ratios. Cytotoxicity studies suggested that all NP formulations are non-toxic. In vitro release of prodrugs from NP showed a biphasic release pattern with an initial burst phase followed by a sustained phase. Such burst effect was completely eliminated when NP were suspended in thermosensitive gels with near zero-order release kinetics. Prodrugs-loaded PLGA NP dispersed in thermosensitive gels can thus serve as a promising drug delivery system for the treatment of anterior eye diseases. Maximum uptake (around 60%) was noted at 3 h for NP. Cellular uptake and intracellular accumulation of prodrugs are significantly different among three stereoisomeric dipeptide prodrugs. The microscopic images show that NP are avidly internalized by HCEC cells and distributed throughout the cytoplasm instead of being localized on the cell surface. Following cellular uptake, prodrugs released from NP gradually bioreversed into parent drug GCV. LLGCV showed the highest degradation rate, followed by LDGCV and DLGCV. LLGCV, LDGCV and DLGCV released from NP exhibited superior uptake and bioreversion in corneal cells. PART 2: PLGA NP of hydrocortisone butyrate (HB) suspended in thermosensitive PLGAPEG- PLGA gel were developed for the treatment of bacterial corneal keratitis. Experimental designs were employed in order to investigate specific effects of independent variables during preparation of HB-loaded PLGA NP and corresponding responses in optimizing the formulation. NP containing HB were prepared by an oil-in-water (O/W) emulsion evaporation technique with different surfactants including polyvinyl alcohol (PVA), pluronic F-108 and chitosan. NP were characterized with respect to particle size, entrapment efficiency, polydispersity, drug loading, surface morphology, zeta potential and crystallinity. In vitro release of HB from NP showed a biphasic release pattern with an initial burst phase followed by a sustained phase. Such burst effect was completely eliminated when NP were suspended in thermosensitive gels and zero-order release kinetics was observed. Percentage of uptake in HCEC after 4 h was 59.09±6.21% for PVA-emulsified NP relative to 55.74±6.26% for pluronic-emulsified NP, and 62.54±3.30% for chitosan-emulsified NP, respectively. In HCEC cell line, chitosan-emulsified NP with chitosan showed highest cellular uptake efficiency over PVA- and pluronic-emulsified NP. However, NP with chitosan indicated significant cytotoxicity under 200 and 500 μg/mL after 48 h, while NP with PVA and pluronic showed no significant cytotoxicity. PLGA NP dispersed in thermosensitive gels can be considered as a promising drug delivery system for the treatment of anterior eye diseases.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Pharmaceutical Sciences (UMKC)

Grantor

University of Missouri--Kansas City

Year dc:date.issued

2015

Author dc:creator

• Yang, Xiaoyan

Advisor dc:contributor.advisor

• Mitra, Ashim K., 1954-

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/10355/46544

OAI identifier oai:identifier

oai:mospace.umsystem.edu:10355/46544