Search

Surface functionalization and cross-linking have been adopted extensively by researchers to customize hydrogel properties, especially in the last decade. The clinical translation of such biomaterials is in a poor state due to long-term toxicity, often beyond the periphery of the short-term animal studies. We endeavor to relook at the material development strategy with all FDA-approved biopolymers in their native states, like gelatin and sodium alginate, without using any functionalization and cross-linking. The fabrication of a cross-linker-free hydrogel has remained one of the main challenges in biomaterial design and requires multiscale structuring of the hydrogels. The physical properties of these hydrogels were enhanced by plasticizers (PEG and glycerol) and a monovalent salt (NaCl). An in-depth analysis suggested that PEG forms a plasticizing layer at the sodium alginate and gelatin interface and glycerol alters the overall polymer structure. The results were further complemented by different characterization methods (scattering techniques and infrared spectroscopy) and molecular dynamics simulations. The detailed microstructural analysis surfaced the enthralling integrated swelling mechanism in gelatin chains that led to high-performing hydrogels.

The Hofmeister series characterizes the ability of salt anions to precipitate polyampholytes/proteins. However, the variation of protein size in the bulk solution of acids and the effect of salts on the same have not been studied well. In this article, the four acids (CH3COOH, HNO3, H2SO4, and HCl) and their effects on the hydrodynamic radius (RH) of gelatin in the bulk solution are investigated. The effects of Na salt with the same anions are also considered to draw a comparison between the interactions of acids and salts with polyampholytes. It is suggested that the interactions of polyampholytes with acids are different from those of salts. The interaction series of polyampholytes with acids with respect to the RH of the polyampholyte is C H 3 CO O − > N O 3 − > C l − > S O 4 2 − whereas the interaction series with salts is S O 4 2 − > C H 3 CO O − > C l − > N O 3 − . These different interactions are due to equilibration between acid dissociation and protonation of polyampholytes. Another important factor contributing to the interactions in weak acids is the fact that undissociated acid hinders the movement of dissociated acid. Experiments and simulations were performed to understand these interactions, and the results were identical in terms of the trend in RH (from the experiments) and the radius of gyration (Rg) (from the simulations). It is concluded that the valence of ions and dissociation affect the interaction in the case of acids. However, the interactions are influenced by the kosmotropic and chaotropic effect, hydration, and mobility in the case of salts. [ABSTRACT FROM AUTHOR]

Present effort intends to improve the performance of gelatin based casted-films for controlled delivery of hydrophobic drugs. To achieve this goal, Piperine (a model drug) was loaded into gelatin (type A) casted-films by solvent evaporation method. Glutaraldehyde was used as a cross-linker for the gelatin films to modulate the drug release behavior and to prolong the rate of degradation of the film.In-vitrodegradation study under physiological conditions and thermal analysis through differential scanning calorimetry were performed to confirm stability of the gelatin casted-film matrix. Aim was to control the drug release from films by varying the cross-linking degree and the gelatin concentration. Optical microscope analysis was performed to study the surface topography of the sample. In order to understand the drug–polymer interaction in the film, attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) analysis was done. Thein-vitrorelease study gave an overall idea of the role of cross-linkers, gelatin concentration, and effect of pH on the release profiles of Piperine. Results show that one can effectively use gelatin casted-film based drug delivery systems for a wide range of release requirements, i.e., from fast release to delayed release. [ABSTRACT FROM PUBLISHER]

[Display omitted] • Hofmeister anions interact reversely for high viscosity negatively charged polymers. • Anions interact based on the sequence for polyelectrolyte/polyampholyte complex. • Anions can be used to tune the properties and drug release profiles. Alginate and gelatin are bio-polymers widely used in drug delivery. A range of salts can be used to achieve the required flexibility in biomaterial design. Hofmeister series gives an idea about the behaviour of salts with proteins. However, its application for the design of biomaterials and their specific effect on high-viscosity polymers and polymer mixtures has not quite been explored. Firstly, this work proposes a strategic interaction-based approach for designing a dual-drug ocular biomaterial. Secondly, the impact of different salt anions on gelatin and alginate mixture for the developed protocols is studied by a proposed method of determining shear-dependent general intrinsic viscosity. Thirdly, shear-dependent intrinsic viscosity is used to determine the interaction amongst the polymers in their mixture, which is then correlated to the release profiles and hydrodynamic radii of polymer mixtures. It is observed that Hofmeister anions behave reversely for high-viscosity negatively charged polymers and depends on the charge densities of the anions. For the polyelectrolyte/polyampholyte complex/mixture, the interactions depend on the addition sequence. It is inferred that the kosmotropes are preferred for protocols where salt is added between gelatin and alginate and chaotropes for protocols where salt is added to the gelatin and alginate complex/mixture in terms of release profiles. [ABSTRACT FROM AUTHOR]

The aim of this study is to develop electrospun gelatin nanofibers based drug delivery carrier to achieve controlled and sustainable release of hydrophobic drug (piperine) for prolonged time. To accomplish this, we devised some strategies such as sandwiching the drug loaded gelatin nanofiber mesh with another gelatin nanofiber matrix without drug (acting as diffusion barrier), sequential crosslinking and finally, a combination of both. As fabricated multilayered electrospun nanofibers mesh was first characterized in terms of degradation study, morphology, drug-polymer interactions, thermal stability followed by studying their release kinetics in different physiological pH as per the gastrointestinal tract. Our results show that with optimized diffusional barrier support and sequential crosslinking together, a zero order sustained drug release up to 48 h may be achieved with a flexibility to vary the drug loading as per the therapeutic requirements. This work lays out the possibility of systematic design of multilayer nano-fiber mesh of a biopolymer as a drug delivery vehicle for hydrophobic drugs with a desired signature of zero order release for prolonged duration. [ABSTRACT FROM AUTHOR]

Delivering hydrophobic drug within hydrophilic polymer matrix as carrier is usually a challenge. Here we report the synthesis of gelatin nanofibers by electrospinning, followed by testing them as a potential carrier for oral drug delivery system for a model hydrophobic drug, piperine. Electrospun gelatin nanofibers were crosslinked by exposing to saturated glutaraldehyde (GTA) vapor, to improve their water resistive properties. An exposure of only 6 min was not only adequate to control the early degradation with intact fiber morphology, but also significantly marginalized any adverse effects associated with the use of GTA. Scanning electron microscopy imaging, Fourier transform infrared spectroscopy and thermogravimetric analysis were done to study nanofiber morphology, stability of drug and effect of crosslinking. The pH of release medium was also varied as per the gastrointestinal tract for in-vitro drug release study. Results illustrate good compatibility of hydrophobic drug in gelatin nanofibers with promising controlled drug release patterns by varying crosslinking time and pH of release medium. [ABSTRACT FROM AUTHOR]

Blend of biodegradable hydrogels like sodium alginate/gelatin (SA/G) usually requires use of chemical cross-linkers to remain stable in aqueous media for drug delivery applications. This study targets the feasibility of having an entire spectrum of a model hydrophobic drug (piperine) release i.e. from burst to controlled release, by varying polymer viscosity and molecular weight of plasticizer with minimal use of cross-linkers. Swelling study, drug-polymer interactions and morphology analysis reveal the impact of viscosity variation on polymer matrix. [ABSTRACT FROM AUTHOR]