NAG-PEGylated multilamellar liposomes for BBB-GLUT transporter targeting

Abstract

The primary objective of the research study is to investigate Glucose (GLUT) transporter targeting of the drug (Citalopram-Hbr) for increased permeability across the Blood-Brain Barrier (BBB). The current study reports the development, physicochemical characterization, cytotoxicity analysis and in-vitro BBB permeability assessment of the Citalopram-Hbr liposomal formulations. Rat Primary Brain Microvascular Endothelial Cells (RPBECs) were used for cytotoxicity analysis and drug permeability testing. Five N-Acetyl Glucosamine (NAG) coated PEGylated multilamellar liposomal formulations were prepared and tested. Permeability of the liposomal formulations was evaluated in RPBECs monolayer. The particle size of the formulations ranged from 13 to 4259 nm. Entrapment efficiency was 50-75%. Cytotoxicity analysis indicated viability (>90%) for all five formulations (0.3-1.25 mg/ml). Apparent drug permeability (Papp) of the formulations ranged from 5.01 × 10⁴ to 15 × 10⁴ cm/min. The study demonstrated successful preparation of NAG-coated PEGylated multilamellar liposomal formulations with high drug entrapment efficiency. Cytotoxicity data indicated that the formulations were well tolerated by the cells up to a concentration of 1.25 mg/ml. Transport study data demonstrated that RPBMECs monolayers can be employed as a robust screening tool for future drug transport studies targeting GLUT transporter on the BBB. The drug permeability values provide a promising preliminarily proof that NAG-coated liposomal formulations can be an effective tool for BBB-GLUT transporter targeting.

Keywords: Analysis & Pharmaceutical Quality; Biopharmaceutics; Blood-Brain Barrier (BBB); Drug Design & Development; Drug Discovery; Glucose (GLUT) Transporter; N-acetyl Glucosamine (NAG); Pharmaceutical Science; Pharmacy; liposomes; transporter targeted drug delivery.

Figure 1.

% of Entrapment Efficiency, number weighted particle size (nm), PDI, Zeta potential (s⁻¹) and In-vitro percentage of drug release at 2 h and 24 h of the five liposomal formulations.

Figure 2.

Represent the Percentage of RPBEMECs viability for the five formulations at 2.5, 1.25, 0.625 and 0.312 mg/mL, respectively. Each data point represents the mean ± SD of four determinations.

Figure 3.

Unidirectional (A-B) transport study through the rat brain endothelial cells monolayer represents Papp (cm/min) of the five liposomal formulations (at 2.5 mg/ml conc.) from 15 min to 180 min. Each data point represents the mean ± SD of four determinations.

Figure 4.

Unidirectional (A-B) transport study through the rat brain endothelial cells monolayer represents Papp (cm/min) of the five liposomal formulations (at 2.5 mg/ml conc.) from 15 min to 180 min. Each data point represents the mean ± SD of four determinations.

Figure 5.

Unidirectional (A-B) flux (min⁻¹) of the five liposomal formulations (2.5 mg/ml) at 15 and 180 min. Each data point represents the mean ± SD of four determinations.

Figure 6.

Schematic representation of GLUT transporter targeting of NAG-Citalopram-HBR on primary brain microvascular endothelial cells and improved absorption of the drug across BBB.