Prajakta Kirankumar Kavathekar

Although many newly developed therapeutic compounds exhibit low bioavailability due to poor aqueous solubility and limited gastrointestinal permeability, oral drug delivery remains the preferred route of administration because of its simplicity, convenience, and high patient compliance. An efficient lipid-based method to get around these restrictions is self-nanoemulsifying drug delivery systems. These nanoscale droplets greatly improve mucosal penetration, surface area for dissolution, and solubilization of the medication. Furthermore, SNEDDS enhances the bioavailability of BCS class II and IV drugs by promoting lymphatic absorption, reducing first-pass metabolism, and maintaining drugs in a solubilised state. System efficiency is mostly determined by critical formulation variables, including droplet size, HLB, lipid selection, surfactant content, and thermodynamic stability. Sustained solubilization, modulation of intestinal permeability, reduced efflux activity, and enhanced lymphatic transport collectively contribute to improved drug absorption. Recent developments have expanded SNEDDS into specialized categories, including ligand-modified targeted SNEDDS for site-specific action, controlled-release SNEDDS for sustained delivery, solid SNEDDS for improved stability and handling, and supersaturated SNEDDS to prevent drug precipitation. These developments have made SNEDDS more adaptable, effective, and patient-friendly. Further studies are anticipated to maximise their therapeutic potential.

Recent advances in nanotechnology have positioned solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) as promising platforms for dermal and transdermal drug delivery. This review critically highlights emerging breakthroughs that go beyond the conventional advantages of lipid nanoparticles. SLNs, composed of physiologically compatible solid lipids, provide improved drug stability and controlled release; however, their clinical utility is often constrained by limited drug loading, drug expulsion during storage, and highly ordered crystalline structures. To overcome these drawbacks, second-generation NLCs incorporate both solid and liquid lipids, creating an imperfect lipid matrix that significantly enhances loading capacity, minimizes drug leakage, and enables tunable release kinetics. Recent formulation innovations including precision high-pressure homogenization, microfluidic-assisted production, and optimized hot/cold homogenization approaches have enabled tighter particle size control, improved batch reproducibility, and better long-term stability. In parallel, surface engineering strategies such as ligand functionalization, polymer coating, and incorporation of natural bioactives have demonstrated enhanced skin targeting, deeper stratum corneum penetration, and prolonged dermal retention. Notably, recent preclinical and translational studies report improved therapeutic outcomes in acne, psoriasis, fungal infections, inflammatory disorders, wound healing, hyperpigmentation, and melanoma-related skin conditions when compared with conventional topical systems. Despite these advances, important translational gaps remain, including large-scale manufacturing challenges, regulatory uncertainties, and limited clinical validation. By integrating recent technological breakthroughs with application-focused evidence, this review provides a forward-looking perspective on the evolving role of SLNs and NLCs as next-generation lipid nanocarriers for dermatological therapy and advanced skin care.