The main aim of this clinical trial is to assess the safety of PN20 in healthy volunteers aged 18 to 50 years. The main questions it aims to answer are:
* Is PN20 safe in adult? Researchers will compare PN20 to a placebo (a look-alike substance that contains no drug) to see if PN20 is safe.
Participants will
* Receive a single dose injection of PN20 or placebo according to weight,
* Stay in hospital for assessment.