In short
Propyl parahydroxybenzoate, also known as propylparaben, is a preservative and antimicrobial ingredient used in some gel formulations for urological procedures. It is not an active anaesthetic itself but appears as a component in Instillagel, a lubricant and local anaesthetic gel being tested against standard lidocaine gel in a Phase 3 trial. The trial enrolled 182 participants undergoing placement or exchange of a double-J ureteral stent.
Propyl parahydroxybenzoate, also known as propylparaben or E216, is a preservative and antimicrobial substance with the chemical formula C10H12O3. It belongs to the paraben family of compounds and is used as an ingredient in various pharmaceutical and cosmetic products. In the clinical trial described here, it appears as a component of Instillagel, a gel used during transurethral procedures.
Table of contents
Key points
- Phase 3 trial comparing Instillagel (containing propyl parahydroxybenzoate) with standard lidocaine gel in transurethral procedures.
- 182 participants are planned for enrolment in this randomised, controlled, double-blind study.
- The trial focuses on placement or exchange of double-J (DJ) ureteral stents.
- The primary outcome is intraoperative pain intensity measured on a 100 mm visual analogue scale (VAS).
- The study is currently authorised but not yet recruiting.
- Propyl parahydroxybenzoate is also known as propylparaben or E216.
What is propyl parahydroxybenzoate?
Propyl parahydroxybenzoate is a chemical preservative belonging to the paraben family. Its chemical formula is C10H12O3, and it is also known by several other names, including propylparaben, E216, Nipagin P, Nipasol, and Tegosept P. The US Food and Drug Administration (FDA) assigns it the unique ingredient identifier (UNII) Z8IX2SC1OH.
In the context of the clinical trial listed in the EU Clinical Trials Information System (CTIS), propyl parahydroxybenzoate is a component of the investigational product Instillagel, a gel used for lubrication and local anaesthesia during urological procedures. It is not itself the active anaesthetic agent; rather, it serves as a preservative within the gel formulation.
How does propyl parahydroxybenzoate work?
As a paraben, propyl parahydroxybenzoate acts as an antimicrobial preservative. Parabens are widely used to prevent the growth of bacteria, yeasts, and moulds in pharmaceutical and cosmetic products. The available source does not describe a specific molecular target or mechanism of action for this substance in the context of pain relief or anaesthesia. In the trial, the therapeutic effect on pain is expected to come from the local anaesthetic component of Instillagel, while propyl parahydroxybenzoate contributes to product stability and preservation.
Which conditions is it used or studied for?
- Placement or exchange of double-J (DJ) ureteral stent — a procedure in which a thin tube is inserted into the ureter to keep it open and allow urine to drain from the kidney to the bladder. The trial investigates whether a gel containing propyl parahydroxybenzoate can reduce pain during this transurethral procedure.
How is propyl parahydroxybenzoate given?
In the clinical trial, propyl parahydroxybenzoate is administered as part of Instillagel, which is a gel. The gel is applied via the urethral route, with a volume of 11 millilitres used during the procedure. The comparator arm receives a standard lidocaine gel at the same volume and by the same route.
What do the clinical trials show?
One clinical trial is registered for this substance in the EU Clinical Trials Information System. It is a Phase 3, multicentre, randomised, controlled, double-blind study comparing the efficacy and safety of Instillagel (the test product, containing propyl parahydroxybenzoate) against standard lidocaine gel in transurethral procedures.
The trial plans to enrol 182 participants who are undergoing placement or exchange of a double-J (DJ) ureteral stent. The study is currently authorised, meaning it has received regulatory approval to proceed but has not yet started recruiting participants.
The primary outcome measure is intraoperative pain intensity, defined as the participant's strongest procedure-related pain experienced during placement or exchange of the DJ ureteral stent. Pain is assessed retrospectively within 5 minutes after completion of the transurethral procedure using a 100 mm visual analogue scale (VAS), where higher values indicate more severe pain. The aim is to demonstrate the superiority of the test product over the comparator in reducing intraoperative pain intensity.
What side effects are known?
The available sources do not provide information on side effects specifically associated with propyl parahydroxybenzoate. The clinical trial is designed to compare the efficacy and safety of the test product versus standard local anaesthesia, and safety outcomes will be collected during the study.