Encapsulation of the dual FLAP/mPEGS-1 inhibitor BRP-187 into acetalated dextran and PLGA nanoparticles improves its cellular bioactivity

Abstract

Background: Dual inhibitors of the 5-lipoxygenase-activating protein (FLAP) and the microsomal prostaglandin E2 synthase-1 (mPGES-1) may exert better anti-inflammatory efficacy and lower risks of adverse effects versus non-steroidal anti-inflammatory drugs. Despite these advantages, many dual FLAP/mPGES-1 inhibitors are acidic lipophilic molecules with low solubility and strong tendency for plasma protein binding that limit their bioavailability and bioactivity. Here, we present the encapsulation of the dual FLAP/mPGES-1 inhibitor BRP-187 into the biocompatible polymers acetalated dextran (Acdex) and poly(lactic-co-glycolic acid) (PLGA) via nanoprecipitation.Results: The nanoparticles containing BRP-187 were prepared by the nanoprecipitation method and analyzed by dynamic light scattering regarding their hydrodynamic diameter, by scanning electron microscopy for morphology properties, and by UV-VIS spectroscopy for determination of the encapsulation efficiency of the drug. Moreover, we designed fluorescent BRP-187 particles, which showed high cellular uptake by leukocytes, as analyzed by flow cytometry. Finally, BRP-187 nanoparticles were tested in human polymorphonuclear leukocytes and macrophages to determine drug uptake, cytotoxicity, and efficiency to inhibit FLAP and mPGES-1.Conclusion: Our results demonstrate that encapsulation of BRP-187 into Acdex and PLGA is feasible, and both PLGA-and Acdex-based particles loaded with BRP-187 are more efficient in suppressing 5-lipooxygenase product formation and prostaglandin E2 biosynthesis in intact cells as compared to the free compound, particularly after prolonged preincubation periods.

Optimized Encapsulation of the FLAP/PGES-1 Inhibitor BRP-187 in PVA-Stabilized PLGA Nanoparticles Using Microfluidics

“…Nanoprecipitation, as a formulation method for NPs, is impressive with its simplicity and efficiency [ 17 ] and was, therefore, applied as the first technique for the encapsulation of BRP-187 ( Figure 1 B) into PLGA particles [ 9 ]. However, the bulk procedure is often limited with respect to increasing the polymer concentration and drug loading without increasing the particle sizes and distributions as well as stability problems [ 9 , 15 ]. To overcome the lack of control and precision during particle formation by bulk preparation, the formulation of BRP-187 in PLGA particles was investigated within a herringbone staggered mixing chip ( Figure 1 A).…”

“…As recently reported by our group, PLGA can be also used for the encapsulation of the anti-inflammatory drug BRP-187 (4-(4-chlorophenyl)-5-(4-(quinoline-2-ylmethoxy)phenyl)isoxazol-3-carboxylic acid) [ 9 ]. This drug was discovered in 2016 within a class of dual inhibitors that are able to reduce the formation of pro-inflammatory mediators without affecting the production of pro-resolving mediators for improved therapy [ 10 , 11 , 12 ].…”

“…In detail, these inhibitors dually block the microsomal prostaglandin E 2 synthase-1 (mPGES-1) as well as 5-lipoxygenase (LO) or 5-LO-activating protein (FLAP) and suppress efficiently prostaglandin E 2 (PGE 2 ) and leukotriene levels without the unfavorable side effects of non-steroidal anti-inflammatory drugs (NSAIDs) [ 10 , 11 , 13 , 14 ]. However, BRP-187 is an acidic lipophilic drug and reveals only poor water solubility along with a strong tendency for plasma protein binding and relies on the entrapment in NPs [ 9 ]. For a first in vitro evaluation of BRP-187-loaded PLGA NPs (PLGA(BRP-187)), a batch co-nanoprecipitation process was applied, and particles with 130 to 168 nm in size and loading capacities (LC) of up to 2.2% to 2.5% were obtained [ 9 ].…”

“…However, BRP-187 is an acidic lipophilic drug and reveals only poor water solubility along with a strong tendency for plasma protein binding and relies on the entrapment in NPs [ 9 ]. For a first in vitro evaluation of BRP-187-loaded PLGA NPs (PLGA(BRP-187)), a batch co-nanoprecipitation process was applied, and particles with 130 to 168 nm in size and loading capacities (LC) of up to 2.2% to 2.5% were obtained [ 9 ]. Improved stability, bioavailability, and efficiency of the BRP-187-loaded NPs compared to the free compound in suppressing 5-LO product formation and PGE 2 biosynthesis in intact cells were observed and underlined the promising perspective for the use of this substance/class of substances in the near future [ 9 ].…”

“…For a first in vitro evaluation of BRP-187-loaded PLGA NPs (PLGA(BRP-187)), a batch co-nanoprecipitation process was applied, and particles with 130 to 168 nm in size and loading capacities (LC) of up to 2.2% to 2.5% were obtained [ 9 ]. Improved stability, bioavailability, and efficiency of the BRP-187-loaded NPs compared to the free compound in suppressing 5-LO product formation and PGE 2 biosynthesis in intact cells were observed and underlined the promising perspective for the use of this substance/class of substances in the near future [ 9 ]. In view of upcoming in vivo studies or clinical applications, the formulation still lacks control and precision, particularly in terms of higher LC values and scale-up possibilities [ 15 , 16 , 17 ].…”