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Optimising the controlled release of dexamethasone from a new generation of PLGA-based microspheres intended for intravitreal administration



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Rodríguez Villanueva, J. and Bravo Osuna, Irene and Herrero Vanrell, Rocío and Molina Martínez, Irene Teresa and Guzmán Navarro, M. (2016) Optimising the controlled release of dexamethasone from a new generation of PLGA-based microspheres intended for intravitreal administration. European Journal of Pharmaceutical Sciences, 92 . pp. 287-297. ISSN 0928-0987


Official URL: https://www.sciencedirect.com/journal/european-journal-of-pharmaceutical-sciences


Successful therapy for chronic diseases affecting the posterior segment of the eye requires sustained drug concentrations at the site of action for extended periods of time. To achieve this, it is necessary to use high systemic doses or frequent intraocular injections, both associated with serious adverse effects. In order to avoid these complications and improve patient`s quality of life, an experimental study has been conducted on the preparation of a new generation of biodegradable poly D-L(lactide-co-glycolide (50:50) (PLGA) polymer microspheres (MSs) loaded with Dxm, vitamin E and/or human serum albumin (HSA). Particles were prepared according to a S/O/W encapsulation method and the 20-40μm fraction was selected. This narrow size distribution is suitable for minimally invasive intravitreal injection by small calibre needles.
Characterisation of the MSs showed high Dxm loading and encapsulation efficiency (> 90%) without a strong interaction with the polymer matrix, as revealed by DSC analysis. MSs drug release studies indicated a small burst effect (lower than 5%) during the first five hours and subsequently, drug release was sustained for at least 30 days, led by diffusion and erosion mechanisms. Dxm release rate was modulated when solid state HSA was incorporated into MSs formulation. SDS-PAGE analysis showed that the protein maintained its integrity during the encapsulation process, as well as for the release study. MSs presented good tolerance and lack of cytotoxicity in macrophages and HeLa cultured cells. After 12 months of storage under standard refrigerated conditions (41ºC), MSs retained appropriate physical and chemical properties and analogous drug release kinetics. Therefore, we conclude that these microspheres are promising pharmaceutical systems for intraocular administration, allowing controlled release of the drug.

Item Type:Article
Uncontrolled Keywords:Intraocular administration; Microspheres; PLGA; Dexamethasone; Human serum albumin; Controlled release; Stability
Subjects:Medical sciences > Pharmacy
Medical sciences > Pharmacy > Pharmacology
Medical sciences > Pharmacy > Pharmaceutical technology
ID Code:51770
Deposited On:13 Mar 2019 12:03
Last Modified:17 May 2019 07:43

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