Design and evaluation of a novel nanoparticulate-based formulation encapsulating a HIP complex of lysozyme

Abstract

Formulation development of protein therapeutics using polymeric nanoparticles has found very little success in recent years. Major formulation challenges include rapid denaturation, susceptibility to lose bioactivity in presence of organic solvents and poor encapsulation in polymeric matrix. In the present study, we have prepared hydrophobic ion pairing (HIP) complex of lysozyme, a model protein, using dextran sulfate (DS) as a complexing polymer. We have optimized the process of formation and dissociation of HIP complex between lysozyme and DS. The effect of HIP complexation on enzymatic activity of lysozyme was also studied. Nanoparticles were prepared and characterized using spontaneous emulsion solvent diffusion method. Furthermore, we have also investigated release of lysozyme from nanoparticles along with its enzymatic activity. Results of this study indicate that nanoparticles can sustain the release of lysozyme without compromising its enzymatic activity. HIP complexation using a polymer may also be employed to formulate sustained release dosage forms of other macromolecules with enhanced encapsulation efficiency.

Reversible hydrophobic ion-paring complex strategy to minimize acylation of octreotide during long-term delivery from PLGA microparticles

“…However, fraction of octreotide complexed declined upon further increment in mole ratio. Similar results were observed with lysozyme and IgG-FAB with these ion-pairing agents (Gaudana et al, 2013; Gaudana et al, 2011; Patel et al, 2014a). This may be due to incomplete charge neutralization in DSA and DSB at higher mole ratio.…”

“…Reversible HIP complex was prepared by simple mixing of solutions containing octreotide and ion-pairing agents at low pH. Citrate buffer (pH 4) was selected to dissolve octreotide and ion-pairing agents based on published reports from our laboratory (Gaudana et al, 2013; Patel et al, 2014a). Octreotide has two pKa, 7 and 10.15 associated with amine of lysine and guanidine group of terminal arginine.…”

“…HIP complex was prepared by simple mixing of aqueous solutions containing ion-pairing agent and octreotide (Gaudana et al, 2013; Gaudana et al, 2011; Patel et al, 2014a). Briefly, stock solutions of octreotide and ion-pairing agents were prepared in 10 mM citrate buffer at pH 4.…”

“…This process can increase hydrophobicity of biologics thereby improving entrapment efficiency in polymeric formulations. It has been shown that peptide/protein retains activity and conformational stability with HIP complex in various studies (Gaudana et al, 2013; Gaudana et al, 2011; Patel et al, 2014a; Shi et al, 2008). We hypothesize that acylation of peptides may be prevented or minimized by masking the reactive nucleophile amine with reversible HIP complex.…”

Long-term delivery of protein therapeutics

“…Incomplete release was because of acylation of BSA 100 . Gaudana et al successfully formulated and characterized hydrophobic ion pairing (HIP) complex of lysozyme (15 kDa), by employing dextran sulfate, a sulfated polysaccharide complexing agent 101 . Spontaneous emulsion solvent diffusion method was utilized to prepare nanoparticles.…”