Calcium alginate nanocarriers as possible vehicles for oral delivery of insulin

Abstract

In the present investigation, alginate nanoparticles have been prepared and characterised by various techniques such as FTIR, SEM, particle size analysis and surface charge measurements. It was found from both the SEM and particle size analysis that average size of the particle was about 40 nm. The particles were loaded with insulin and the release kinetics of insulin was studied in PBS medium. The results indicated that when percent loading increases from 11.7 to 38.9, the released amount of insulin increased from 18% to 60% of the loaded drug. The effect of composition of nanoparticles, pH and temperature of the release medium was examined on the amount of released insulin. It was observed when that amount of alginate in the feed mixture was varied from 1.0 to 2.0 g, the prepared nanoparticles showed a decreasing tendency to release insulin. Similarly, upon increasing the concentration of crosslinker in the range 0.5-1.1 mM, the release of insulin constantly decreased. The chemical stability of the loaded drug was assessed especially under highly acidic conditions of artificial gastric juice and it was noticed that even in harsh acidic environment (pH 1.2) the insulin remains chemically stable. The in vitro blood compatibility of nanoparticles was also investigated and it was found that for a definite composition of nanoparticles, protein adsorption and percent haemolysis were minimum which suggested for an optimum blood compatibility of alginate nanoparticles of definite composition. Thus, it can be conclusively stated that the calcium alginate nanoparticles prepared by emulsion crosslinking method show potential to be developed as oral formulation for insulin delivery.

Alginate nanoparticles protect ferrous from oxidation: Potential iron delivery system

“…Around pH 5, the negatively charged carboxylate groups of alginate polymer are electrostatically linked with calcium ions. Since pKa value of alginate lies between 3.4 to 4.4 (Goswami, et al, 2014), the alginate biopolymer will be present as dissociated carboxylate ions around pH 5 facilitating the efficient crosslinking with calcium ions.…”

“…According to Goswami et al, the release of insulin from alginate nanoparticles at pH 1.2 was less than 20% while it was 90% at pH 7.4 because at low gastric pH alginate forms a compact acid-gel structure restricting the release of drug from the matrix and also protecting the drug from harsh environmental conditions (Goswami, et al, 2014). Another important factor is that the pKa of alginate lies well above 3.4, hence in very highly acidic medium, alginate remains undissociated protecting the encapsulated drug.…”

Glucose‐Triggered Insulin Release from Fe3+‐Cross‐linked Alginate Hydrogel: Experimental Study and Theoretical Modeling

“…Among many different drug‐delivering systems, insulin‐releasing systems, particularly those activated by glucose as the triggering signal are of special interest because of their potential use to treat diabetes mellitus . While numerous synthetic materials have been suggested for controlled delivery of insulin, alginate‐based materials are promising because of their biocompatibility . Indeed, alginate—a natural biocompatible polymer—has been frequently used in many different biomedical applications …”

“…[13] While numerous synthetic materials have been suggested for controlled delivery of insulin, [14] alginate-based materials are promising because of their biocompatibility. [15][16][17] Indeed, alginate-an aturalb iocompatible polymer [18,19] -has been frequently used in many different biomedical applications. [20,21] Alginate polymer can be cross-linked with multivalent metal cations (Ca 2 + cations are the most utilized cross-linkers) producingahydrogel capable of encapsulationa nd then controlledr elease of various biomolecules, including proteins/enzymes, [22][23][24][25][26] DNA, [27,28] and other (bio)molecular species, for example,d rugs.…”

Recent Advances in Encapsulation, Protection, and Oral Delivery of Bioactive Proteins and Peptides using Colloidal Systems

“…Oral administration of this delivery system to rats was again shown to lead to better control of blood glucose levels in the animals. Insulin-loaded microgels have also been formed from alginate and calcium using an emulsion-template method [140]. A simulated digestion study showed that the insulin remained trapped inside these particles under gastric conditions, but was released under small intestine conditions.…”