Fast-dissolving ocular films of riboflavin acetate conjugate for treatment of keratoconus in UVA-CXL procedure: ex vivo permeation, hemolytic toxicity and apoptosis detection

Optimizing riboflavin delivery with co-crystal and in situ hydrogel formulations for management of keratoconus: A comprehensive investigation with in vitro, ex vivo and in vivo studies

Keratoconus is a progressive disease characterized by corneal thinning and conical deformation. Corneal cross-linking, a common treatment, strengthens collagen fibers using vitamin B2 (riboflavin) and UVA light. However, the surgical removal of the corneal epithelium (Epi-Off) required for riboflavin penetration causes complications and may affect treatment success. To address this, research has focused on delivering riboflavin without removing the epithelium (Epi-On). In this study, riboflavin-based hydrogel and co-crystal formulations were developed and evaluated through in vitro, ex vivo, and in vivo studies. Co-crystals were prepared using trehalose, dextrose, mannitol, and nicotinamide as agents, employing solvent evaporation and co-mixing methods. These formulations were characterized using DSC (Differential Scanning Calorimetry), XRD (X-Ray Diffraction), and FTIR (Fourier Transform Infrared Spectroscopy), identifying 1R1N (1 unit mol riboflavin and 1 unit mol nicotinamide co-crystals) and 1R1M (1 unit mol riboflavin and 1 unit mol mannitol co-crystals) groups as promising candidates. Thermosensitive hydrophilic gels containing riboflavin or riboflavin-5-phosphate sodium and Transcutol P (a permeation enhancer) were also developed, using Pluronic F-127 as the polymer. The 18 % Pluronic F-127 gel formed at 31.4 ± 0.2 °C. Drug release studies showed faster release from riboflavin-5-phosphate sodium formulations, while ex vivo retention studies revealed higher corneal retention for co-crystals. In vivo studies on rat corneas demonstrated superior drug concentrations for riboflavin formulations compared to riboflavin-5-phosphate sodium, with hydrophilic gels showing prolonged corneal contact time. The THJ-TP formulation (Riboflavin-5-phosphate sodium and permeation enhancer (Transcutol P) containing hydrophilic gel formulations), containing riboflavin-5-phosphate sodium and Transcutol P, emerged as the most promising candidate. This research represents a significant advancement towards a non-invasive riboflavin-based treatment for keratoconus.

Next Steps in 3D Printing of Fast Dissolving Oral Films for Commercial Production

3D printing technique has been utilised to develop novel and complex drug delivery systems that are almost impossible to produce by employing conventional formulation techniques. For example, this technique may be employed to produce tablets or Fast Dissolving oral Films (FDFs) with multilayers of active ingredients, which are personalised to patient's needs. In this article, we compared the production of FDFs by 3D printing to conventional methods such as solvent casting. Then, we evaluated the need for novel methods of producing fast dissolving oral films, and why 3D printing may be able to meet the shortfalls of FDF production. The challenges of producing 3D printed FDFs are identified at commercial scale by referring to the identification of suitable materials, hardware, qualitycontrol tests and Process Analytical Technology. In this paper, we discuss that the FDF market will grow to more than $1.3 billion per annum in the next few years and 3D printing of FDFs may share part of this market. Although companies are continuing to invest in technologies, which provide alternatives to standard drug delivery systems, the market for thin-film products is already well established. Market entry for a new technology such as 3D printing of FDFs will, therefore, be hard, unless, this technology proves to be a game changer. A few approaches are suggested in this paper.