Raman Microspectroscopy as a Tool to Elucidate the Efficacy of Topical Formulations Containing Curcumin

Abstract

The success of the onychomycosis treatment is directly associated with factors such as the choice of the medication, the administration route, and the pharmaceutical formulation. Photodynamic therapy (PDT) is an emerging and promising technique indicated for onychomycosis treatment. For this application, the main challenge is the efficient delivery of the photosensitizer (PS). Curcumin is widely used as a PS, however it is an unstable molecule and it is a challenge to develop a formulation with good penetration into the nail plate, maintaining the stability of curcumin. In this study, the molecular mechanisms underlying the efficacy of two topical formulations containing curcumin used in a clinical trial for onychomycosis treatment were analyzed by Raman microspectroscopy. It is shown that curcumin is present in both formulations in aggregated and non-aggregated states, and in aggregates it is present in different conformations, depending on the interaction with the solvent. This proves to be critical for efficient and uniform PS delivery to the nail and its complete use during the treatment. These analyses are showing how promising Raman microspectroscopy is in understanding the molecular mechanisms of the efficiency of photosensitizers and are helping to improve the development of pharmaceutical formulations.

Combination of Photodynamic Therapy and Oral Antifungals for the Treatment of Onychomycosis

“…Studies have demonstrated the effectiveness of PDT in onychomycosis patients using different photosensitizers, such as aminolevulinate (ALA) [10], MAL [6], MB [11] and rose Bengal [12], curcumin [13], and compared its efficacy in monotherapy with available drugs [14]. PDT appears to be more effective than amorolfine for the treatment of non-dermatophyte onychomycosis [15].…”

Innovative Approaches for Drug Discovery: Quantifying Drug Distribution and Response with Raman Imaging

“…Raman imaging has been implemented for direct, quantitative mapping of drug compounds in topical formulations and their delivery into the skin and appendages. − For example, drug delivery and absorption events were interrogated at the interface between porcine skin and (trans)­dermal formulations . A depth profile of nicotine penetration into the SC after patch application indicated that nicotine transport was nearly steady-state after the patch was applied for 2 h. Raman mapping was also used to characterize unwanted fentanyl structural and chemical changes when the adhesive delivery system was improperly used .…”

Spectral imaging of pharmaceutical materials with a compact terahertz difference-frequency generation semiconductor source

“…A THz source based on intra-cavity difference-frequency generation (DFG) in a two-wavelength mid-infrared quantum cascade laser (QCL) integrated with two different laser active regions 12 uses mid-infrared active regions engineered to exhibit a large second-order nonlinear susceptibility c (2) for an efficient THz DFG process. In 2015, by introducing the homogeneous active region concept, the performance of THz DFG sources was dramatically improved.…”