PERLANE® is comprised of biotechnologically engineered, non-immunogenic, stabilized hyaluronic acid gel particles, and has patent protection until at least 2017. The primary difference between RESTYLANE® and PERLANE® is that the hyaluronic acid gel particles in PERLANE® are larger than those found in RESTYLANE®. PERLANE® is intended to be implanted into the deep dermis to superficial layer of the sub cutis to add volume to restore surface contour in facial wrinkles and folds. The three-dimensional gel particles in RESTYLANE® and PERLANE® are hydrophilic molecules, attracting and binding to water molecules as they degrade, helping to maintain volume augmentation for about six months. Also distinct from other hyaluronic acid dermal fillers, RESTYLANE® and PERLANE® are minimally cross-linked, making them similar to the natural hyaluronic acid found in the body.