Sustained release of ibuprofen from polymeric micelles with a high loading capacity of ibuprofen in media simulating gastrointestinal tract fluids

Structural Investigation on How Guest Loading of Poly(2-oxazoline)-Based Micelles Affects the Interaction with Simulated Intestinal Fluids

Drug loading of polymer micelles can have a profound effect on their particle size and morphology as well as their physicochemical properties. In turn, this influences performance in biological environments. For oral delivery of drugs, the intestinal environment is key, and consequently, a thorough structural understanding of what happens at this material-biology interface is required to understand in vivo performance and tailor improved delivery vehicles. In this study, we address this interface in vitro through a detailed structural characterization of the colloidal assemblies of polymeric micelles based on poly(2-oxazolines) with three different guest loadings with the natural product curcumin (17-52 wt %) in fed-state simulated intestinal fluids (FeSSIF). For this, we employ NMR spectroscopy, in particular, 1H NMR, 1H-1H-NOESY, and 1H DOSY experiments complemented by quantum chemical calculations and cryo-TEM measurements. Through this mixture of methods, we identified curcumin-taurocholate interactions as central interaction patterns alongside interactions with the polymer and lipids. Furthermore, curcumin molecules can be exchanged between polymer micelles and bile colloids, an important prerequisite for their uptake. Finally, increased loading of the polymer micelles with curcumin resulted in a larger number of vesicles as taurocholate─through coordination with Cur─is less available to form nanoparticles with the lipids. The loading-dependent behavior found in this study deviates from previous work on a different drug substance highlighting the need for further studies including different drug molecules and polymer types to improve the understanding of events on the molecular level.

Newly developed nano-biocomposite embedded hydrogel to enhance drug loading and modulated release of anti-inflammatory drug

A newly developed iron-based nano-biocomposite (nano Fe-CNB) impregnated alginate formulation (CA) is proposed to improve drug loading and exhibit pH-responsive behavior of model anti-inflammatory drug-ibuprofen for controlled release applications. The proposed formulation is investigated with conventional β-CD addition in CA. The nano Fe-CNB-based formulations with and without β-CD, (Fe-CNB β-CD CA and Fe-CNB CA) are compared with only CA and β-CD incorporated CA formulations. The results indicate the incorporation of nano-biocomposite or β-CD into CA enhances the drug loading (>40%). However, pH-responsive controlled release behavior is observed for nano Fe-CNB based formulations only. The release studies from Fe-CNB β-CD CA indicate ∼ 45% release in stomach pH (1.2) within 2 h. In contrast, Fe-CNB CA shows ∼20% release only in stomach pH and improved release (∼49%) at colon pH (7.4). The rheology and swelling studies indicate Fe-CNB CA remains intact in stomach pH with a minimal drug release, but it disintegrates at colon pH due to charge reversal behavior of nano-biocomposite and ionization of polymeric chains. Thus, Fe-CNB CA formulation is found to be a potential candidate for targeting colon delivery, inflammatory bowel disease, and post-operative conditions.

ROS-responsive copolymer micelles for inflammation triggered delivery of ibuprofen

Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used for the treatment of pain, inflammation and fever. However, most NSAIDs are poorly water soluble, making it difficult to be administered thus high doses are required to reach the intended therapeutic effect, resulting in associated side effects. In this study, ROS-responsive micellar systems based on a block copolymer consisting of methylpropyl thioether (MTPA) and N'N-dimethylacrylamide was developed and loaded with ibuprofen (IBU). Using lipopolysaccharide activated RAW 264.7 macrophage like cells, we demonstrated that IBU was released from the copolymer, specifically in the presence of ROS. Interestingly, IBU encapsulated in ROS-responsive nanoparticles exhibited greater anti-inflammatory potency compared to its free form. The work highlights the potential of the ROS-responsive micellar system developed in this work to be used as carrier of NSAIDs for the treatment of relevant inflammatory conditions.

Amphiphilic poly(caprolactone-b-N-hydroxyethyl acrylamide) micelles for controlled drug delivery

To increase the bioavailability and water solubility of hydrophobic medicine, an amphiphilic block copolymer, polycaprolactone-block-polyhydroxyethyl acrylamide (PCL-b-PHEAA), was synthesized.

Tailorable degradation of pH-responsive all polyether micelles via copolymerisation with varying acetal groups

A facile approach with random copolymers composed of two epoxide monomers bearing different acetal groups realizes the tunable kinetics of micelle degradation.

A novel smart PEGylated gelatin nanoparticle for co-delivery of doxorubicin and betanin: A strategy for enhancing the therapeutic efficacy of chemotherapy

Betanin (BET) can reduce the side effects of potent anticancer drugs e.g. doxorubicin (DOX) on the normal tissues in co-administration with them because of the synergistic therapeutic effect and consequently the reduced required amount of anticancer agents. Despite interest in the use of BET, incomplete oral absorption and low stability of BET limit its application. Thus, in this study to overcome the restrictions of BET and providing the synergistic effect of DOX@BET, we designed a new pH-responsive nanocarrier via decoration of gelatin nanoparticles (GNPs) by (methoxy poly (ethylene glycol)-poly ((2-dimethylamino) ethyl methacrylate-co-itaconic acid) (PGNPs). DOX and BET were effectively loaded (the loading capacity of 20.5% and 16.25%, respectively) into the PGNPs and this nanoplatform exhibited the suitable small particle size (162 nm). Additionally, the triggered release ability of drugs was studied through the assessment of simulated physiological and tumor tissue environments and showed the controlled release of DOX and BET with adjusting the pH of environment. Moreover, the synergistic effect of DOX@BET loaded PGNPs decreased the cell viability amount of breast cancer cells (MCF-7) respect to the free form of DOX or BET which indicated that the developed smart nanocarrier will be a hopeful nanocarrier for cancer therapy.

Development of Chitosan-Based pH-Sensitive Polymeric Micelles Containing Curcumin for Colon-Targeted Drug Delivery

pH-sensitive N-naphthyl-N,O-succinyl chitosan (NSCS) and N-octyl-N,O-succinyl chitosan (OSCS) polymeric micelles carriers have been developed to incorporate curcumin (CUR) for colon-targeted drug delivery. The physical entrapment methods (dialysis, co-solvent evaporation, dropping, and O/W emulsion) were applied. The CUR-loaded micelles prepared by the dialysis method presented the highest loading capacity. Increasing initial amount of CUR from 5 to 40 wt% to polymer resulted in the increase in loading capacity of the polymeric micelles. Among the hydrophobic cores, there were no significant differences in the loading capacity of CUR-loaded micelles. The particle sizes of all CUR-loaded micelles were in the range of 120-338 nm. The morphology of the micelles changed after being contacted with medium with different pH values, confirming the pH-responsive properties of the micelles. The release characteristics of curcumin from all CUR-loaded micelles were pH-dependent. The percent cumulative release of curcumin from all CUR-loaded micelles in simulated gastric fluid (SGF) was limited to about 20%. However, the release amount was significantly increased after contacted with simulated intestinal fluid (SIF) (50-55%) and simulated colonic fluid (SCF) (60-70%). The released amount in SIF and SCF was significantly greater than the release of CUR from CUR powder. CUR-loaded NSCS exhibited the highest anti-cancer activity against HT-29 colorectal cancer cells. The stability studies indicated that all CUR-loaded micelles were stable for at least 90 days. Therefore, the colon targeted, pH-sensitive NSCS micelles may have potential to be a prospective candidate for curcumin delivery to the colon.

Synthesis and characterization of pH-responsive N-naphthyl-N,O-succinyl chitosan micelles for oral meloxicam delivery

The aim of this study was to synthesize pH responsive chitosan and to evaluate the influence of drug-loaded micelle methods on loading efficiency, particle size and micelle stability. N-naphthyl-N,O-succinyl chitosan (NSCS) was successfully synthesized and meloxicam (MX) was loaded into the inner core of the NSCS micelles by physical entrapment methods (dialysis, O/W emulsion, dropping and evaporation) with a regular spherical shape (particle size 84-382nm). MX-loaded micelles by evaporation method showed the highest entrapment efficiency. The stability of the drug-loaded micelles depended on not only the methods but also the initial of drug. NSCS micelles are less toxic on Caco-2 cells. In acidic medium at 0-2h, percentage cumulative release of MX from MX-loaded micelles was similar to free drug. When the pH was adjusted to pH 6.8, the MX release was increased significantly. Therefore, this NSCS micelle would be desirable to develop MX carrier for oral drug delivery.