# Biodegradability and Efficacy of Porous Polycaprolactone Microsphere Dermal Filler for Fine Lines

## TL;DR

This study shows that a biodegradable dermal filler made of porous polycaprolactone microspheres safely degrades in the body and effectively reduces wrinkles.

## Contribution

The study provides new evidence on the biodegradability and wrinkle-reducing efficacy of porous PCL microsphere fillers in both in vitro and in vivo models.

## Key findings

- Porous PCL microspheres degrade over time, with surface cracks and reduced molecular weight observed in vitro.
- In vivo tests showed safe degradation and collagen production in rabbit tissues over 30 months.
- The filler improved skin roughness in a photoaging mouse model, confirming its anti-wrinkle effect.

## Abstract

Among various filler products designed to improve facial wrinkles, those using biodegradable polymer microspheres have gained attention. Recently, a filler composed of porous polycaprolactone (PCL) microspheres was introduced.

This study aimed to evaluate and understand the mechanism of PCL biodegradability, safety, and efficacy in reducing wrinkles.

To examine the degradation characteristics in vitro, the filler product was incubated in phosphate‐buffered saline (pH 7.4) at 37°C, 45°C, and 55°C. Samples from 1 to 104 weeks were obtained to determine changes in the morphology and molecular weight of the porous PCL microspheres. In addition, the product was administered to rabbits to evaluate its in vivo degradability. Treated tissues were sampled at 6, 12, 18, 24, and 30 months to examine the biodegradability of the microspheres. Tissue safety and collagen fiber production were evaluated at the same time points. The anti‐wrinkle effect was evaluated using PRIMOS to measure changes in skin surface roughness in a photoaging mouse model.

In vitro testing revealed that the porous PCL microspheres degraded progressively over time, forming cracks on the surface and showing a decrease in molecular weight. In vivo studies demonstrated that the product degraded safely in tissues and induced collagen formation. Furthermore, skin roughness evaluation using a photoaging mouse model confirmed its anti‐wrinkle effects.

The filler product based on porous PCL microspheres was found to be safely biodegraded in vivo and effectively improved wrinkles.