SOL Group :: PD 125/2020

Chlorpromazine loading and irradiation into hydrogels by UV laser radiation, as alternative to bacterial infected wound treatment

Summary

The number of drug-resistant bacteria is currently growing up, and the possibilities for successful treatment are narrow due to the lack of solutions in eradicating them. To overcome the emergence of multiple drug-resistant bacteria it is necessary to identify new approaches in using the existing drugs and to find ‘smart’ drug delivery systems.

The discovery of compounds with direct antimicrobial effects obtained by laser irradiation of a drug is a further step in filling the gap created in antimicrobial research and represents a new approach in chemistry, biology, and pharmacology. In this respect, irradiated chlorpromazine (CPZ) proved to be an antimicrobial agent against resistant bacteria. More, conventional drug delivery methods are overwhelmed by repeated dosage of drugs and their systemic toxicity. An alternative is hydrogels that offer optimized therapeutic action of the drug and minimize the disadvantages of classical delivery method.

This proposal is addressing the use of UV laser radiation for exposure of a mixture of polymer-CPZ to form hydrogels with already irradiated CPZ in it, thus eliminating the process of CPZ separate irradiation and loading. This kind of hydrogels may be applied in wound dressing for patients that show infected wounds with various bacterial pathogens resistant to antibiotics.

The project has an interdisciplinary nature, combining antimicrobial and laser spectroscopy research. It aims to provide new data on physics, chemistry, and biology of hydrogel formation and loading with drug solutions. The project’s results may have an important impact in future extensive use of laser modified compounds in medicine, pharmacology and patient care.

Expected results

The overall objective of the proposal is to find the best way to deliver the chlorpromazine (CPZ) irradiated solutions for wound dressings in view of obtaining the best antimicrobial effect. In this respect, it is proposed to use UV photo-crosslinked hydrogels. The first part of the project aims to determine the hydrogel with the best-controlled release of irradiated CPZ. The second part aims to use the selected hydrogel and to photopolymerize the mixture CPZ-polymer. This means that unirradiated CPZ will be added to the polymer and all together will be exposed to UV laser radiation. Thus, the final product will be a hydrogel that will contain the irradiated CPZ. This method will help to eliminate the drug loading process and drug irradiation, being cost-effective compared to the classical method.

The estimated result are: *antimicrobial efficacy of unirradiated and irradiated chlorpromazine loaded hydrogels; *hydrogel formation by photopolymerize the mixture of polymer-photoinitiator-chlorprom azien; *hydrogel formation by photopolymerize the mixture of polymer-chlorpromazine; *antimicrobial/antibiofilm efficacy of chlorpromazine loaded and irradiated throughout the photopolymerization; *publish 3 articles; *project website, *participate at 3 international conferences, *two research stage in an EU country institute.

Obtained results

Within this project, the following were realized: *update the concept of the project to last-minute published progress to adapt the research to reach the aims specified in the project proposal; *irradiation of chlorpromazine (CPZ) solutions using 266 nm from Nd:YAG at 6.5 mJ; *determination of the photoinitiator rate of free radical production during irradiation; *development of the experimental system for obtaining hydrogels; *conducting test to obtain hydrogels by photopolymerization of Irgacure 2959 (0.05%, 0.35%, and 0.7%) + GelMa (10%), Irgacure 2959 (0.7%) + GelMa (15%), Riboflavin (0, 05%, 0.7%) + L-arginine (0.1%) + PEGDa (10%), Irgacure 2959 (0.05%, 0.35%, and 0.7%) + PEGDa (10%); *fabrication of gelatin methacrylate (GelMa) hydrogel by photopolymerization using Irgacure 2959; *characterization of hydrogel: swelling measurements, UV-Vis and FTIR absorption spectroscopy, scanning electron microscopy (SEM), LIF; *unirradiated and irradiated CPZ loading into GelMa hydrogels. *characterization of the loaded hydrogel: UV-Vis and FTIR absorption spectroscopy, SEM, LIF, and LIF lifetime, drug release assay; *susceptibility tests of Gram-positive bacteria to GelMa hydrogels loaded with unirradiated and irradiated CPZ; *photopolymerize the mixture of GelMa-Irgacure 2959-CPZ in view of hydrogel formation and characterization by UV-Vis and FTIR absorption spectroscopy, SEM, LIF, and drug release assay; *photopolymerize the mixture of GelMa-CPZ in view of hydrogel formation and characterization; *susceptibility test of Gram-positive bacteria to GelMa hydrogels loaded with unirradiated and irradiated CPZ.

GelMa 10% - CPZ hydrogels (1, 2, 4 mg/mL) obtained after irradiation for 1 and 5 min, even if showed antimicrobial activity against MRSA, began to degrade after 24 h immersion in PBS, so they are not good candidates for controlled release of CPZ. For Irgacure 0.05%-GelMa 10%-CPZ hydrogels (1, 2, 4 mg/mL), even though all of them showed a strong antimicrobial effect, only Irgacure 0.05%-GelMa 10%-CPZ 1 mg/mL irradiated for 1 min released irradiated CPZ for up to 84 h, making it the best hydrogel in terms of antimicrobial activity and drug release obtained in this project.

Project Team