Hydrogels based on poly(methyl vinyl ether-co-maleic acid) and Tween 85 for sustained delivery of hydrophobic drugs

Abstract

Hydrogels based on poly(methyl vinyl ether-co-maleic acid) and Tween 85 were prepared for hydrophobic drug delivery. The hydrogels were synthesized following a simple procedure carried out in solid state. The process did not require the use of any solvent and, as it is based on an esterification reaction, no toxic by-products were obtained. The resulting hydrogels contained Tween 85 inside the structure and due to the amphiphilic nature of this compound, hydrophobic domains within the hydrogel structure were formed. The obtained hydrogels showed good swelling capacities ranging from 100% to 600%. The esterification reaction that took place between poly(methyl vinyl ether-co-maleic acid) and Tween 85 was confirmed by infrared spectroscopy. Hydrogels were loaded with a hydrophobic drug model, Curcumin (CUR), showing that the hydrogels were able to retain up to 36 mg of CUR per g of hydrogel. Additionally, the synthesized hydrogels provided in vitro sustained CUR release over periods of up to 30 days. Finally, and due to the mucoadhesive nature of the prepared materials, one of the hydrogels was tested in vitro as an oral drug delivery system. For this purpose, the selected material was milled into microparticles (45-90 µm diameter). The release of CUR from the microparticles was evaluated under simulated gastric and intestinal conditions. The microparticles were able to release their cargos in 7 h. However, further work is required to optimize this system for oral drug delivery applications.

Poly(methyl vinyl ether-co-maleic acid) Hydrogels Containing Cyclodextrins and Tween 85 for Potential Application as Hydrophobic Drug Delivery Systems

“…Figure 5 shows the surface of DX loaded hydrogels and no DX crystals can be observed in these materials. Similar behavior has been observed in the past for several hydrophobic drugs loaded in GAN/T85 based hydrogels (20) and β-cyclodextrin containing hydrogels (37). Figure 6A shows the loading of DX for all the synthesized hydrogels.…”

“…T10 present pores in the surface but its wettability is better due to the presence of the surfactant. The presence of T85 in hydrogels has been reported to increase the porosity of the surface in previous work (20). Interestingly, T5B5 presents a high degree of porosity in the surface similar to the one obtained in T10.…”

“…1070 cm -1 ). The formation of new ester bonds has been reported in the past for GAN-based materials as a shift in the carbonyl peak (20). The reported peak shift indicates the presence of a new ester peak that is overlapping with the previous acid peak (31).…”

“…T85 based hydrogels showed a better wettability as the contact angles were lower. This is not surprising as T85 is a surfactant, the hydrophilic moieties of the hydrogel will be exposed in the surface while the hydrophobic sections will be forming hydrophobic domains within the interior of the material (20,34). The influence of the composition of the hydrogels on the contact angle can be seen in Figure 4B.…”

“…Researchers have used various methods to improve the loading and homogeneity of hydrophobic drugs in hydrogels, including the incorporation of hydrophobic drug-containing moieties such as surfactants, micelles and/or hydrophobic molecules (12)(13)(14)(16)(17)(18)(19). Surfactants provide micellar and/or hydrophobic domains within the hydrogel structure, thus, improving the loading of hydrophobic drugs (20). Another approach to improve hydrogel compatibility with hydrophobic drugs is the incorporation of molecules which have the ability to form inclusion complexes, such as cyclodextrins (CDs) (18,21).…”