Interactions among proteins and hydrophobically modified polyelectrolytes

Abstract

A special class of hydrophobically modified polyelectrolytes was studied wherein poly(acrylic acid) (PAA) was conjugated with Pluronic F127 NF surfactant. The Pluronic-PAA copolymer solutions form gels at low concentrations when exposed to bodytemperature. Such gels possess enhanced retention in topical applications. Circular dichroism spectra indicate that tertiary structures of human insulin, haemoglobin, and albumin were stabilized in solutions of Pluronic-PAA. Aggregation of insulin in gelled solutions of Pluronic-PAA was impeded as demonstrated in shaking tests. The presence of Pluronic-PAA hindered the insulin degradation by alpha-chymotrypsin by at least 7-fold. Extraction of calcium ions from trypsin by Pluronic-PAA led to the dramatic changes in the tertiary structure and total loss of enzymatic activity, suggesting that Pluronic-PAA could inhibit tryptic degradation of proteins.

Role of a Novel Excipient Poly(Ethylene Glycol)-b-Poly(L-Histidine) in Retention of Physical Stability of Insulin in Aqueous Solutions

“…Bromberg synthesized a special class of hydrophobically modified polyelectrolytes wherein poly(acrylic acid) was conjugated with Pluronic F-127 surfactant. The presence of Pluronic-PAA did not induce any significant structural change in insulin (43). It is interesting to note that both Pluronic-PAA and insulin had a negative net charge.…”

Thermoreversible-mucoadhesive Gel for nasal delivery of sumatriptan

“…23,24 Indications also exist that Pluronic poly(acrylic acid) (PAA) can also bind Ca 2+ in biological milieu. 25 Enhancement of the absorption of drugs loaded into Pluronic-PAA microgels through the epithelial cell monolayer of the upper small intestine has been reported by one of the research groups. …”

Drug Carrier Systems Using Chitosan for Non Parenteral Routes

“…Chitosan based systems have the potential for improving the retention and biodistribution of drugs applied topically onto the eye. One of the pharmaceutical forms most investigated are the in situ gels, which have been developed to prolong the precorneal resident time of the drug and to improve ocular bioavailability [121][122][123][124][125][126]. The interaction and prolonged residence time of fluorescence-labelled nanoparticles prepared with chitosan was reported showing, these colloidal drug carriers remained attached to the cornea and the conjunctiva for at least 24 h [127].…”