Biomedical Applications of Lumazine Synthase.

Lumazine synthase (LS) is a family of enzyme involved in the penultimate step in the biosynthesis of riboflavin. Its enzymatic mechanism has been well defined, and many LS structures have been solved using X-ray crystallography or cryoelectron microscopy. LS is composed of homooligomers, which vary in size and subunit number, including pentamers, decamers, and icosahedral sixty-mers, depending on its species of origin. Research on LS has expanded beyond the initial focus on its enzymatic function to properties related to its oligomeric structure and exceptional conformational stability. These attributes of LS systems have now been repurposed for use in various biomedical fields. This review primarily focuses on the applications of LS as a flexible vaccine presentation system. Presentation of antigens on the surface of LS results in a high local concentration of antigens displayed in an ordered array. Such repetitive structures enable the cross-linking of B-cell receptors and result in strong immune responses through an avidity effect. Potential issues with the use of this system and corresponding solutions are also discussed with the objective of improved utilization of the LS system in vaccine development.

Preparation and in vitro evaluation of a pluronic lecithin organogel containing ricinoleic acid for transdermal delivery.

The present study deals with the preparation and in vitro evaluation of a Pluronic lecithin organogel gel containing ricinoleic acid for transdermal delivery. Blank Pluronic lecithin organogel gels were prepared using ricinoleic acid as the oil phase and characterized for pH, viscosity, gelation temperature, and microscopic structure. The optimized Pluronic lecithin organogel gel formulation was further evaluated using ketoprofen (10%) and dexamethasone (0.5%) as model drugs. The stability and in vitro permeability of ketoprofen and dexamethasone was evaluated and compared with the corresponding control formulation (Pluronic lecithin organogel gel made with isopropyl palmitate as the oil phase). The pH and viscosity of blank Pluronic lecithin organogel gel prepared with ricinoleic acid was comparable with the isopropyl palmitate Pluronic lecithin organogel gel. The thixotropic property of ricinoleic acid Pluronic lecithin organogel gel was found to be better than the control. Drug-loaded Pluronic lecithin organogel gels behaved in a similar manner and all formulations were found to be stable at 25 degrees C, 35 degrees C, and 40 degrees C for up to 35 days. The penetration profile of dexamethasone was similar from both the Pluronic lecithin organogel gels, while the permeability for ketoprofen from Pluronic lecithin organogel gel containing ricinoleic acid was found to be three times higher as compared to the control formulation.