In search of a biocompatible implant for the collection of small deficiencies within the dermal corium as in wrinkles and acne scars, polymethylmethacrylate (PMMA) microspheres, 10 to 63 µm in diameter, were dispersed in Tween 80 medium and injected intradermally and subdermally into the abdominal skin of rats. Histological examination of specimens for up to 7 months revealed a modest tissue reaction, forming a delicate fibrous capsule around each individual microsphere within 4 months. Foreign body giant cells were seen rarely (in up to 1.5% of all cells). No breakdown, corrosion, or phagocytosis of the spheres was observed at 7 months. The Tween 80 dispersion medium did not produce any histologically detectable reaction.
Because PMMA products (Paladon, Palacos) have been used in medicine for almost 50 years without causing biological degradation or cancer, the material may be applied safely in the form of microspheres (Arteplast) in corium and subcutis of human patients with wrinkles or acne scars.