Injectability as a function of viscosity and dosing materials for subcutaneous administration

Area of Science:

• Pharmaceutical Technology
• Biomedical Engineering
• Drug Delivery Systems

Background:

• Injectability is crucial for parenteral drug administration, encompassing preparation, administration, ergonomics, and patient comfort.
• Assessing injection forces and needle characteristics is vital for optimizing drug delivery devices.

Purpose of the Study:

• To evaluate the injectability of antisense oligonucleotide solutions.
• To determine optimal dosing materials and needle configurations for parenteral administration.
• To establish acceptable force limits for user-administered injections.

Main Methods:

• Force measurements including expulsion, needle penetration, and needle-bending forces.
• Expulsion time measurements with 18 human participants.
• In vivo injections utilizing a porcine model.
• Assessment of various syringe and needle dimensions (inner diameter, length, wall thickness).

Main Results:

• An injection force exceeding 80 N was found difficult for most individuals.
• A maximum acceptable injection force of 40 N is proposed, with a target of 20 N recommended for autoinjectors.
• Short (6-8 mm) thin-wall needles were identified as preferable for enhancing patient comfort.

Conclusions:

• Optimal injectability is achieved through careful selection of dosing materials and needle specifications.
• Minimizing injection force is critical for improving patient experience and adherence.
• Short, thin-wall needles significantly enhance patient perception and comfort during subcutaneous injections.