Pulmonary arterial hypertension (PAH) is a progressive and debilitating disease characterized by elevated blood pressure in the pulmonary arteries, leading to right heart failure and high mortality rates. Conventional treatments are often limited by poor solubility and bioavailability of therapeutic agents, especially lipophilic phytoconstituents such as curcumin and quercetin, which have shown potential in mitigating PAH symptoms. Solid lipid nanoparticles (SLNs) have emerged as promising nanocarriers that can enhance the solubility and bioavailability of these lipophilic compounds. SLNs are submicron-sized particles composed of biocompatible and biodegradable lipids that encapsulate lipophilic phytoconstituents, protecting them from degradation and improving their pharmacokinetic profiles. This review explores the formulation techniques, characterization, and clinical applications of SLNs in the context of PAH. Key preparation methods, including high shear homogenization, ultrasonication, and solvent emulsification-evaporation, are discussed, alongside strategies for optimizing particle size, zeta potential, and encapsulation efficiency. Clinical translation of SLNs remains challenging due to scalability, reproducibility, and regulatory hurdles. However, advances in targeted delivery systems and personalized medicine approaches hold promise for overcoming these barriers. This review highlights the potential of SLNs to revolutionize PAH treatment by enhancing the solubility and bioavailability of lipophilic phytoconstituents, paving the way for more effective and safer therapeutic options.