Design of novel injectable cationic microspheres based on aminated gelatin for prolonged insulin action

Cranial repair-promoting effect of oxidised sodium alginate/amino gelatine injectable hydrogel loaded with deer antler blood peptides

This study aimed to enhance the treatment of bone defects and increase peptide bioavailability. To achieve this, antioxidant-active peptides (DBPs) were extracted from deer antler blood and incorporated into an oxidised sodium alginate/amino gelatine injectable hydrogel (OSA/N-Gel). This bioscaffold was created through the Schiff base reaction, resulting in the development of an injectable hydrogel comprising OSA, amino gelatine, and deer antler blood peptides (OSA/N-Gel/DBP). OSA/N-Gel/DBP is characterised by a loose and porous structure that enhances nutrient flow and confers good degradability, enabling the gradual release of DBP to meet the long-lasting treatment requirements for bone repair. In vitro, 5-Ethynyl-2'-deoxyuridine (EDU), alkaline phosphatase (ALP), and Alizarin Red S (ARS) staining showed the pro-proliferative and pro-mineralising abilities of OSA/N-Gel and OSA/N-Gel/DBP on osteoblasts (MC3T3). OSA/N-Gel/DBP effectively promoted the expression of osteogenesis-related genes, such as ALP and vascular endothelial growth factor (CD31), and deposition of collagen (COL-1), and activated the wingless-related integration site (Wnt) signalling pathway, thereby promoting bone regeneration. The effect of OSA/N-Gel/DBP was significantly superior to that of the OSA/N-Gel group, indicating that DBP has good osteogenic properties. We successfully repaired bone defects and broadened the application of antler blood, thereby providing a novel approach to treating bone defects.

Exploring Protein-Based Carriers in Drug Delivery: A Review

Drug delivery systems (DDSs) represent an emerging focus for many researchers and they are becoming progressively crucial in the development of new treatments. Great attention is given to all the challenges that a drug has to overcome during its journey across barriers and tissues and all the pharmacokinetics modulations that are needed in order to reach the targeting sites. The goal of these pathways is the delivery of drugs in a controlled way, optimizing their bioavailability and minimizing side effects. Recent innovations in DDSs include various nanotechnology-based approaches, such as nanoparticles, nanofibers and micelles, which provide effective targeted delivery and sustained release of therapeutics. In this context, protein-based drug delivery systems are gaining significant attention in the pharmaceutical field due to their potential to revolutionize targeted and efficient drug delivery. As natural biomolecules, proteins offer distinct advantages, including safety, biocompatibility and biodegradability, making them a fascinating alternative to synthetic polymers. Moreover, protein-based carriers, including those derived from gelatin, albumin, collagen, gliadin and silk proteins, demonstrate exceptional stability under physiological conditions, and they allow for controlled and sustained drug release, enhancing therapeutic efficacy. This review provides a comprehensive overview of the current trends, challenges, and future perspectives in protein-based drug delivery, focusing on the types of proteins adopted and the techniques that are being developed to enhance their functionality in terms of drug affinity and targeting capabilities, underscoring their potential to significantly impact modern therapeutics.

Nature-Inspired Gelatin-Based Adhesive Hydrogel: A Rapid and User-Friendly Solution for Hemostatic Applications

Conventional hemostatic agents face challenges in achieving rapid hemostasis and effective tissue repair due to limited hemostatic scenarios, suboptimal efficacy, and inadequate adhesion to wet tissues. Drawing inspiration from nature-sourced materials, a gelatin-based adhesive hydrogel (AOT)  is designed, easily prepared and quick to form, driven by Schiff base and multiple hydrogen bonds for applications in arterial and liver bleeding models. AOT exhibits exceptional adhesion to wet tissues (48.67 ± 0.16 kPa) and displays superior hemostatic properties with reduced blood loss and hemostatic time compared to other hydrogels and conventional hemostatic materials. Moreover, AOT exhibits good biocompatibility and biodegradability. In summary, this easily prepared adhesive hydrogel has the potential to supplant traditional hemostatic agents, offering a novel approach to achieve swift sealing of hemostasis and facilitate wound healing and repair in broader application scenarios, owing to its unique advantages.

Fabrication and characterization of PCL/CaCO3 electrospun composite membrane for bone repair

CaCO₃/casein microspheres were entrapped in PCL membranes using electrospinning to mimic the hierarchical structure of ECM in bone. The composite membranes showed enhanced biomineralization property, proliferation and osteogenic differentiation potential of HMSCs.

Enhancement of the dissolution rate and gastrointestinal absorption of pranlukast as a model poorly water-soluble drug by grinding with gelatin

The effect of grinding with gelatin on the dissolution behavior and gastrointestinal absorption of a poorly water-soluble drug was evaluated using the antiasthmatic agent, pranlukast, as a model poorly water-soluble drug. A ground pranlukast-gelatin mixture was prepared by grinding equal quantities of pranlukast and gelatin. In the dissolution testing, the dissolution rate of pranlukast in the suspension of the ground pranlukast-gelatin mixture under conditions of pH 3.0, 5.0 and 7.0 was markedly faster than that in the suspension of pranlukast. According to powder X-ray diffractometry (PXRD) and differential scanning calorimetry (DSC) analysis, the enhanced dissolution rate of pranlukast produced by grinding with gelatin was caused by changing the crystalline state of pranlukast into an amorphous state. In an animal experiment, the bioavailability of pranlukast following oral administration of the ground pranlukast-gelatin mixture to rats was threefold greater than that following administration of pranlukast. In the in vitro permeation experiment, the amount of permeated pranlukast through Caco-2 cell monolayers after application of the ground pranlukast-gelatin mixture was greater than that after application of pranlukast. These results suggest that the enhancement of the gastrointestinal absorption of pranlukast by grinding with gelatin is due to enhancement of the dissolution rate. Grinding a poorly water-soluble drug with gelatin is a useful method of enhancing its gastrointestinal absorption.

Development of Drug Delivery Systems for Targeting to Macrophages

Drug delivery systems (DDS) using liposomes as drug carriers for targeting to macrophages have been developed for the treatment of diseases that macrophages are related to their progress. Initially, DDS for the treatment of atherosclerosis are described. The influence of particle size on the drug delivery to atherosclerotic lesions that macrophages are richly present and antiatherosclerotic effects following intravenous administration of liposomes containing dexamethasone (DXM-liposomes) was investigated in atherogenic mice. Both the drug delivery efficacy of DXM-liposomes (particle size, 200 nm) to atherosclerotic lesions and their antiatherosclerotic effects were greater than those of 70 and 500 nm. These results indicate that there is an optimal particle size for drug delivery to atherosclerotic lesions. DDS for the treatment of respiratory infections are then described. The influence of particle size and surface mannosylation on the drug delivery to alveolar macrophages (AMs) and antibacterial effects following pulmonary administration of liposomes containing ciprofloxacin (CPFX-liposomes) was investigated in rats. The drug delivery efficacy of CPFX-liposomes to AMs was particle size-dependent over the range 100-1000 nm and then became constant at over 1000 nm. These results indicate that the most effective size is 1000 nm. Both the drug delivery efficacy of mannosylated CPFX-liposomes (particle size, 1000 nm) to AMs and their antibacterial effects were significantly greater than those of unmodified CPFX-liposomes. These results indicate that the surface mannosylation is useful method for drug delivery to AMs. This review provides useful information to help in the development of novel pharmaceutical formulations aimed at drug targeting to macrophages.

A Novel Preparation Method for Microspheres of Water Soluble Polymers Using Polypropyleneglycol as the Dispersion Medium

Polypropyleneglycol (PPG) was used as a dispersion medium for the preparation of microspheres (MS) consisting of starch, gelatin, whey protein or dextran. Aqueous solutions of the polymers were dispersed in PPG at various initial temperatures and then the systems were cooled to 0.5 degrees C to allow water in the dispersed phase to dissolve in PPG. The particle size of the starch-MS was dependent on the initial temperature of PPG in the preparation process. There were two different processes for particle generation in the procedure. One of them was via the formation of a temporary emulsion during the early phase of dispersion of the aqueous polymer solution into PPG. The other was via the stable emulsion in which the aqueous polymer solution was dispersed in water-saturated PPG. The particle size generated in the former process was dependent on the initial temperature: a high temperature gave large particles but a low temperature gave small particles, while that in the latter process was temperature-independent. This preparation method for MS will be useful for the formulation of heat-sensitive material, such as protein-containing drugs.

Aminated gelatin microspheres as a nasal delivery system for peptide drugs: Evaluation of in vitro release and in vivo insulin absorption in rats

Aminated gelatin microspheres (AGMS) was investigated as a nasal drug delivery system for peptide drugs. The in vitro drug release from microspheres was evaluated using a fluorescein-labeled insulin (RITC-insulin) and FITC-dextran with a molecular weight of 4.4 kDa (FD-4) as model drugs. RITC-insulin release from AGMS was significantly slower than from native gelatin microspheres (GMS), with a cumulate release of 18.4% and 32.4% within 30 min, and 56.9% and 75.1% within 8 h respectively. However, the release of FD-4 from both AGMS and GMS was quite rapid and no difference was observed for the two microspheres. The electrostatic interactions between the model drugs and the microspheres were supposed to be the main factor that controlled the release behavior. The absorption enhancing effect was estimated by measuring the changes of plasma glucose concentrations of healthy rats following intranasal administration of insulin-incorporated microspheres in both suspension and dry powder forms. AGMS could significantly increase the nasal absorption of insulin in rats when administered in a dry powder formulation, but no significant hypoglycemic effect was observed when given in suspensions. One of the mechanisms for the increased insulin absorption was attributed to the hydrogel nature of the microspheres that could absorb water from the nasal mucosa and thus resulted in a temporarily dehydration of the epithelium membrane and opening of the tight junctions. The positive charge of the AGMS has also evidently contributed to the absorption enhancing effect. In addition, the mucoadhesive properties of AGMS might also have played a role to the total effect. AGMS might be a new candidate carrier for the nasal delivery of peptide drugs.