Poly-d,l-lactic Acid (PDLLA) Application in Dermatology: A Literature Review

Abstract

Poly-d,l-lactic acid (PDLLA) is a biodegradable and biocompatible polymer that has garnered significant attention in dermatology due to its unique properties and versatile applications. This literature review offers a comprehensive analysis of PDLLA's roles in various dermatological conditions and wound-healing applications. PDLLA demonstrates significant benefits in enhancing skin elasticity and firmness, reducing wrinkles, and promoting tissue regeneration and scar remodeling. Its biodegradable properties render it highly suitable for soft tissue augmentation, including facial and breast reconstruction. We discuss the critical importance of understanding PDLLA's physical and chemical characteristics to optimize its performance and safety, with a focus on how nano- and micro-particulate systems can improve delivery and stability. While potential complications, such as granuloma formation and non-inflammatory nodules, are highlighted, effective monitoring and early intervention strategies are essential. PDLLA's applications extend beyond dermatology into orthopedics and drug delivery, owing to its superior mechanical stability and biocompatibility. This review underscores the need for ongoing research to fully elucidate the mechanisms of PDLLA and to maximize its therapeutic potential across diverse medical fields.

Keywords: biocompatible materials; dermal fillers; filler; poly lactic acid; poly-d,l-lactic acid; scar remodeling; skin rejuvenation.

Figure 2

SEM image of the PDLLA (The image was provided in courtesy of VAIM Inc., Republic of Korea with the product Juvelook) [7]. The PDLLA microparticles are spherical in shape with multiple pores on the surface, and have a diameter of 30–70 µm. The microparticle size of both PDLLA monomers make them small enough to pass through an injection needle, but large enough to protect them from phagocytosis. The PLAs may have adverse effect of nodule formation, however, PDLLA produced by VAIM Inc. has foamy structures which can be degrades using energy-based devices.

Figure 1

Poly(D,L-lactic acid) (PDLLA) exhibits superior mechanical stability and biocompatibility compared to poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA) due to its unique stereoisomeric composition, which results in an amorphous polymer structure. PLLA is hemicrystalline and has a regular chain structure, whereas PDLLA is amorphous and has an irregular chain with random distribution of L- and D-lactic acids. This structure prevents the formation of large crystalline regions that are typically found in PDLA and PLLA, making PDLLA less brittle and more resistant to mechanical stress. PDLLA’s homogeneous distribution of D- and L-lactic acid monomers allows for controlled and predictable degradation, which is crucial in biomedical applications where the timing of polymer breakdown affects therapeutic outcomes. Moreover, PDLLA’s gradual and uniform degradation produces smoother degradation products, reducing the likelihood of inflammatory responses, while its primary degradation product, lactic acid, is naturally metabolized by the body, further enhancing its biocompatibility. These properties make PDLLA an advantageous material for use in dermatological treatments and wound-healing applications. The D-form and L-form monomers are bonded in random order, maximizing the contact surface area, which is why PDLLA is widely used in orthopedics and drug delivery.

Figure 3

Needleless injectors utilizing various force mechanisms for liquid jet formation. (a) Compressed spring: a spring is compressed, and when released, it drives a piston that pushes the liquid to form a jet. (b) Pressurized gas: a chamber filled with pressurized gas expels the liquid by driving a piston forward, creating a jet. (c) Voice coil: an electromagnetic voice coil generates motion when current is applied, moving the piston and creating a liquid jet. (d) Piezo-element: a piezoelectric element expands and contracts under an applied voltage, propelling the liquid to form a jet. (e) Laser-induced: a laser creates a bubble within the liquid, generating pressure that drives the liquid out as a jet. Each modality demonstrates a different approach to achieve high-speed liquid injection without the use of needles.

Figure 4

This figure illustrates the biochemical pathways and cellular interactions through which PDLLA contributes to skin rejuvenation in aged skin. PDLLA initiates a series of responses starting with the phosphorylation and activation of nuclear factor erythroid 2-related factor 2 (NRF2). This activation promotes the polarization of macrophages towards the anti-inflammatory M2 phenotype, which increases the production of interleukin-10 (IL-10). The elevated IL-10 levels lead to reduced senescence and increased proliferation of adipose-derived stem cells (ASCs), enhancing their paracrine effects through the secretion of transforming growth factor-beta (TGF-β) and fibroblast growth factor 2 (FGF2). Arrows pointing up represents upregulation while downward represents down regulation.