Evaluation of porphyrin loaded dry alginate foams containing poloxamer 407 and β-cyclodextrin-derivatives intended for wound treatment

Abstract

Dry alginate foams intended for antibacterial photodynamic therapy (aPDT) of infected wounds were prepared. aPDT is a treatment modality involving light of appropriate wavelength, oxygen and a photosensitizer (PS) to produce radicals that attack biological targets (e.g. bacteria). The hydrophobic 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin (THPP) was chosen as a model PS and loaded into the foams. The foams contained a poloxamer (Pluronic F127) and/or β-cyclodextrin (βCD)-derivatives, i.e. methylβCD (MβCD), heptakis(2,6-di-O-methyl)-βCD (HkβCD) or hydroxypropylβCD (HPβCD).The physical characteristics of the various foams prepared and the THPP load, release and photostability were evaluated. All the foams were thin and flexible and could easily be handled and cut to fit a potential wound. Fast disintegration were observed for dry foams in water or phosphate buffered saline, while in Hanks' balanced salt solution the foams absorbed liquid without losing their integrity. All the foams had a similar THPP load of 0.12-0.13% w/w. The presence of βCD-derivatives improved THPP release, however, no differences were observed between the different types of βCD-derivatives evaluated. THPP loaded into the foams was photolabile, which induced a color change combined with fading. Alginate foams formulated with PF127, βCD-derivatives and THPP demonstrated applicability as delivery vehicles for PSs in aPDT of wounds.

Alginate in Wound Dressings

“…The percentage of drug loaded onto the foam was between 0.12–0.13% w / w . The release of the drug was influenced by the presence of β-cyclodextrin derivatives [ 87 ].…”

Marine Algae Polysaccharides as Basis for Wound Dressings, Drug Delivery, and Tissue Engineering: A Review

“…However, their use requires frequent dressing change; foams do not suit dry wounds and wounds with little exudate [5]. Thus, alginate-based foams loaded with antibacterial agents have been developed for treating infected wounds [77,78].…”

Porphyrinoid–Cyclodextrin Assemblies in Biomedical Research: An Update

“…Biocompatible hydrogels are generated from alginates, polysaccharide polymers produced from brown algae, which form hydrogels by ionic cross-linking in the presence of divalent cations. Dry foams of alginates have been evaluated as carriers for delivery of photosensitizers for aPDT on infected wounds using THPP as a model PS . Cross-linked alginates are mixed with THPP, along with poloxamer PF127 (a micelle forming triblock copolymer of propylene and ethylene oxides acting both as foaming agent and THPP solubilizer).…”

“…Dry foams of alginates have been evaluated as carriers for delivery of photosensitizers for aPDT on infected wounds using THPP as a model PS. 165 Cross-linked alginates are mixed with THPP, along with poloxamer PF127 (a micelle forming triblock copolymer of propylene and ethylene oxides acting both as foaming agent and THPP solubilizer). The cyclodextrin derivatives rMeβCD, HPβCD, and 2,6-DMβCD have been tested in the quadruple alginate/THPP/PF127/CD assemblies in various well-defined ratios, either in addition to or instead of PF127 in order to alleviate aggregation of the THPP through inclusion complex formation.…”