(T1130-03-21) Use of High-Pressure Homogenization to Prepare a Nano-suspension for Intravenous Administration

Purpose: The purpose of this research was to develop an intravenous (IV) infusion formulation of NYR-BI02 to support a canine preclinical study, where a solution concentration greater than 50 mg/mL was required. Poor solubility in a range of suitable co-solvents resulted in a nano-suspension being pursued. Bead milling can be used for nano-suspension manufacture; however, challenges with scalability and glass contamination (3) meant that high-pressure homogenization was evaluated to prepare the formulation

Methods: Saturated solubility was determined in a range of excipients using a 24-hour shake-flask method. Samples were filtered, diluted, and analysed by UPLC-PDA (Waters Acquity UPLC). Bead-milling with 1 mm zirconium beads was performed to screen the dispersion properties of a range of polymers and surfactants (PEG 400, Poloxamer 188, TPGS and Lecithin). Particle size distribution was determined by laser diffraction (Sympatec Helos Cuvette) and propensity for aggregation via Polarised Light Microscopy (PLM) (Nikon). The lead formulations were subsequently prepared by using a High-Pressure Homogeniser (IKA) – with 5 cycles each at 500, 1000 and 1500 bar followed by 2 cycles at 1700 bar. The resulting suspensions were evaluated by Dynamic Light Scattering (DLS) (Malvern Zetasizer). Physical stability under ambient and refrigerated conditions was assessed by DLS and chemical stability by UPLC-PDA. The lead formulation was manufactured and dosed to dogs (n=3), via a single bolus IV injection, alongside a solution-based formulation consisting of 5% DMAC, 5% Solutol HS15 and 90% saline in an in-vivo PK (pharmacokinetic) study.

Results: Following bead miling, four dispersant systems were identifed as producing well-dispersed suspensions – 0.5% Poloxamer 188, 0.2% TPGS, 0.5% Poloxamer 188 and 0.2% TPS and 0.5% Poloxamer 188 and 0.5% Lecithin (Figure 1). The four dispersant systems were transferred to the high-pressure homogenizer for nanosuspension manufacture (up to 70 mg/mL NYR-BI02), followed by filtration through a 0.8 µm Nalgene CN filter. 0.5% Poloxamer gave the best particle size distribution ( < 700 nm) and was selected for stability assessment. The nanosuspension was considered to be stable at 50 mg/mL NYR-BI02 over two weeks under ambient and refrigerated conditions, with no significant increase in particle size observed (Figure 2). The nanosuspension was optimized for osmolality (378 mOsm) with addition of 0.8% trehalose and 0.15% NaCl. The 50 mg/mL nanosuspension was diluted to 5 mg/mL for a proof-of-concept dog PK study, where adult male non-naïve dogs were administered with a single IV bolus dose of 5 mg/mL of the nanosuspension formulation or 5 mg/mL concentration of the solution formulation. The developed nanosuspension slightly improved plasma levels compared to an equivalent dose solution formulation (5 mg/kg) in dogs. (Figure 3) Additionally no adverse effects were observed and there was less inter-animal variability with the nanosuspension compared to the solution formulation.

Conclusion: Nanosuspensions can aid tolerability as solubility can be improved without the use of less tolerable excipients, particularly in dogs where there is a more limited range of tolerable excipients. High pressure homogenisation allows for scalable manufacture of nanosuspensions without the risk of glass contamination making it a safe and viable method of manufacture. Nanosuspensions can be used to formulate poorly soluble drugs for parenteral applications, particularly in the pre-clinical stage where higher dose concentrations are required.

References: 1. Patel D, Zode SS, Bansal AK, 2020, ‘Formulation aspects of intravenous nanosuspensions’, International Journal of Pharmaceutics, V 586, 119555.
2. Frank KJ, Boeck G, 2016, ‘Development of a nanosuspension for iv administration: From miniscale screening to a freeze-dried formulation’, European Journal of Pharmaceutical Sciences, V 87, pp 112-117.
3. Müller RH and Peters K, 1998 ‘Nanosuspensions for the formulation of poorly soluble drugs I. Preparation by a size-reduction technique’, International Journal of Pharmaceutics, V 160 pp 229-237.

Polarized Light Microscopy of suspensions following bead milling.

Effect of storage on Particle Size Distribution of the nano-suspension

PK results of nanosuspension vs. solution formulation after IV bolus dose to dogs at 5mg/kg