1. Computational Studies of PLGA Microspheres inside an Injection
Needle
Shravan Uppala1,2
, Amjad Basha Mohammad1
, Sudarshan Mahapatra1
, Sharad Shrivatsava2
, Krishna
Mohan Vattipalli1,*
1
Advanced Characterization Techniques Lab, Integrated Product Development Organization, Dr.
Reddy’s Laboratories, Hyderabad, Telangana
2
Mechanical Engineering Department, BITS Pilani, Pilani, Rajasthan
Abstract:
Biodegradable polymers are used extensively in the drug delivery systems. Microspheres made of
these polymers (PLGA, PGA, PLA, PEG etc.) play a significant role in targeted drug delivery
approaches. Studying and understanding the physico-chemical properties of these microspheres is of
utmost importance for the formulation of the product. In addition to studying the particle size
distribution, drug release, drug packaging, thermal properties, crystallization property and other
aspects for the microspheres, one has to understand the delivery modes of these microspheres into the
human system. While delivering into the subcutaneous zones, these microspheres tend to agglomerate
in the syringe needle and hence build an enormous amount of reverse pressure thereby leading to a
disturbance inducing severe pain to patient at the time of the drug delivery. This agglomeration and
flow of the microspheres through the needle is simulated and presented with the potential issues that
could create the disturbance in the delivery. An injection needle according to literature specification
was created, designed and modelled. The flow ability of the suspension media along the needle was
studied at various scenarios – simple flow, particle agglomeration at various positions, particle
agglomerations of various sizes that dominate the diameter of the side wall. Results indicate the
disruption in the laminar flow of the media and provide the possible solution for minimal agglomerate
size that is acceptable from the injectability perspective.