Development of β-cyclodextrin/polyvinypyrrolidone-co-poly (2-acrylamide-2-methylpropane sulphonic acid) hybrid nanogels as nano-drug delivery carriers to enhance the solubility of Rosuvastatin: An in vitro and in vivo evaluation

Cyclodextrin-grafted redox-responsive hydrogel mediated by disulfide bridges for regulated drug delivery

In this paper, a novel mono-methacrylated β-cyclodextrin (β-CD) monomer mediated by disulfide bond was synthesized, and then thermal copolymerized with HEMA monomer in the presence of a little crosslinker to prepare redox-responsive hydrogel for regulated drug delivery. The structure of the monomer was confirmed by FTIR, 1H NMR, 13C NMR spectroscopy. The substitution degree of polymerizable methacrylated group grafted onto β-CD was about 1 by calculating by1H NMR (0.987) and element analysis (0.937). The mono-methacrylated β-CD monomer can well copolymerize with 2-hydroxyethyl methacrylate (HEMA) monomer with gel fraction over 80%. The hydrogel shows low cytotoxicity, and copolymerization of the mono-methacrylated β-CD monomer in the hydrogels increases its equilibrium swelling degree (ESD) and tensile strength, while its transmittance slightly decreases. Drug loading and release rate are dependent on the β-CD content. The hydrogel with high β-CD content of 13.83 wt% shows 1.8 and 8.5 folds puerarin (PUE) and curcumin (CUR) loading than pure pHEMA hydrogel, respectively. The incorporation of β-CD sustained drug release, especially CUR release was prolonged more than 24 h from 5 h of pure pHEMA hydrogel (80% release). The hydrogels are highly sensitive to reduced glutathione (GSH), and low concentration of GSH of 3 mM can significantly accelerate drug release rate. The higher of β-CD content, the more sensitive the hydrogels to GSH, resulting in rapider drug release rate.

Crosslinked PVA-g-poly(AMPS) Nanogels for Enhanced Solubility and Dissolution of Ticagrelor: Synthesis, Characterization, and Toxicity Evaluation

In this study, we synthesized PVA-g-poly(AMPS) nanogels with the aim of enhancing the solubility and dissolution of ticagrelor (TGR). Ticagrelor, a noncompetitive, reversible P2Y12 receptor antagonist, is prescribed to treat acute coronary syndrome. Ticagrelor has restricted oral bioavailability (≈36%) because of its poor solubility and permeability. The free radical polymerization methodology was employed to synthesize nanogels with varied concentrations of poly(vinyl alcohol) (polymer), 2-acrylamido-2-methylpropanesulfonic acid (monomer), and N,N-methylene bis(acrylamide) (crosslinker). The prepared nanogels were analyzed by swelling studies, % drug entrapment efficiency (DEE), solubility studies, in vitro drug release studies, zeta sizer, Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The optimized formulation (PA5) revealed a particle size of 45.86 nm, with a polydispersity index (PDI) of 0.41 and a %DEE of 85.1%. FTIR spectroscopy, XRD, and SEM confirmed the formation of crosslinked nanogels with amorphous and porous structures, and TGA/DSC proved their thermal stability. In vitro dissolution studies showed 99.91% drug release, and the ticagrelor solubility from the synthesized formulations was significantly improved up to 8.2-fold. All formulations followed the Korsmeyer-Peppas model with the Fickian diffusion as the release mechanism. The toxicity studies carried out on rats and the MTT assay on the Caco-2 cell line validated the biocompatibility of the nanogel formulations. The outcomes of the current study led to the conclusion that the PVA-g-poly(AMPS) nanogels synthesized by us could be used as dedicated pharmaceutical delivery systems to achieve enhanced solubility and dissolution of ticagrelor.

Mixed Pluronic/lecithin micelles formulation for oral bioavailability of candesartan cilexetil drug: in vitro characterization and in vivo pharmacokinetic investigations

OBJECTIVE

This study aimed to develop a mixed polymeric micelle formulation incorporating candesartan cilexetil (CAND) drug to enhance its oral bioavailability for the better treatment of hypertension.

METHODS

A Box-Behnken design was utilized to optimize the CAND-incorporated mixed polymeric micelles formulation (CAND-PFLC) consisting of Pluronics (P123 and F68) and lecithin (LC). The optimized CAND-PFLC micelles formulation was characterized for size, shape, zeta potential, polydispersity index (PDI), and entrapment efficiency (%EE). An in vitro release study, ex vivo permeability investigation, and an in vivo pharmacokinetic analysis were carried out to evaluate the performance of the formulation.

RESULTS

The optimized CAND-PFLC micelles formulation demonstrated a spherical shape, a particle size of 44 ± 2.03 nm, a zeta potential of -7.07 ± 1.39 mV, a PDI of 0.326 ± 0.06, and an entrapment efficiency of 87 ± 3.12%. The formulation exhibited excellent compatibility, better stability, and a noncrystalline nature. An in vitro release study revealed a faster drug release of 7.98% at gastric pH in 2 hrs and 94.45% at intestinal pH within 24 hrs. The ex vivo investigation demonstrated a significantly enhanced permeability of CAND, with 94.86% in the micelle formulation compared to 9.03% of the pure drug. In vivo pharmacokinetic analysis showed a 4.11-fold increase in oral bioavailability of CAND compared to the marketed formulation.

CONCLUSION

The CAND-PFLC mixed micelle formulation demonstrated improved performance compared to pure CAND, indicating its potential as a promising oral drug delivery system for the effective treatment of hypertension.

Topical Delivery of Terbinafine HCL Using Nanogels: A New Approach to Superficial Fungal Infection Treatment

This study investigated pH-responsive Terbinafine HCL (TBH)-loaded nanogels as a new approach to treating superficial fungal infections. Acrylic acid (AA) is a synthetic monomer that was crosslinked with a natural polymer (gelatin) using a free radical polymerization technique to fabricate gelatin-g-poly-(acrylic acid) nanogels. Ammonium persulphate (APS) and N, N'-methylene bisacrylamide (MBA) were used as the initiator and crosslinker, respectively. Developed gelatin-g-poly-(acrylic acid) nanogels were evaluated for the swelling study (pH 1.2, 5, 7.4), DEE, particle size, FTIR, thermal stability (TGA, DSC), XRD, SEM, DEE, and in vitro drug release study to obtain optimized nanogels. Optimized nanogels were incorporated into 1% HPMC gel and then evaluated in comparison with Lamisil cream 1% for TBH stratum corneum retention, skin irritation, and in vitro and in vivo antifungal activity studies. Optimized nanogels (AAG 7) demonstrated a 255 nm particle size, 82.37% DEE, pH-dependent swelling, 92.15% of drug release (pH) 7.4 within 12 h, and a larger zone of inhibition compared to Lamisil cream. HPMC-loaded nanogels significantly improved the TBH skin retention percentage, as revealed by an ex vivo skin retention study, indicating the usefulness of nanogels for topical use. In vivo studies conducted on animal models infected with a fungal infection have further confirmed the effectiveness of nanogels compared with the Lamisil cream. Hence, Gelatin-g-poly-(acrylic acid) nanogels carrying poorly soluble TBH can be a promising approach for treating superficial fungal infections.

Imidazo-Pyrazole-Loaded Palmitic Acid and Polystyrene-Based Nanoparticles: Synthesis, Characterization and Antiproliferative Activity on Chemo-Resistant Human Neuroblastoma Cells

Neuroblastoma (NB) is a childhood cancer, commonly treated with drugs, such as etoposide (ETO), whose efficacy is limited by the onset of resistance. Here, aiming at identifying new treatments for chemo-resistant NB, the effects of two synthesized imidazo-pyrazoles (IMPs) (4G and 4I) were investigated on ETO-sensitive (HTLA-230) and ETO-resistant (HTLA-ER) NB cells, detecting 4I as the more promising compound, that demonstrated IC50 values lower than those of ETO on HTLA ER. Therefore, to further improve the activity of 4I, we developed 4I-loaded palmitic acid (PA) and polystyrene-based (P5) cationic nanoparticles (P5PA-4I NPs) with high drug loading (21%) and encapsulation efficiency (97%), by a single oil-in-water emulsification technique. Biocompatible PA was adopted as an emulsion stabilizer, while synthesized P5 acted as an encapsulating agent, solubilizer and hydrophilic-lipophilic balance (HLB) improver. Optic microscopy and cytofluorimetric analyses were performed to investigate the micromorphology, size and complexity distributions of P5PA-4I NPs, which were also structurally characterized by chemometric-assisted Fourier transform infrared spectroscopy (FTIR). Potentiometric titrations allowed us to estimate the milliequivalents of PA and basic nitrogen atoms present in NPs. P5PA-4I NPs afforded dispersions in water with excellent buffer capacity, essential to escape lysosomal degradation and promote long residence time inside cells. They were chemically stable in an aqueous medium for at least 40 days, while in dynamic light scattering (DLS) analyses, P5PA-4I showed a mean hydrodynamic diameter of 541 nm, small polydispersity (0.194), and low positive zeta potentials (+8.39 mV), assuring low haemolytic toxicity. Biological experiments on NB cells, demonstrated that P5PA-4I NPs induced ROS-dependent cytotoxic effects significantly higher than those of pristine 4I, showing a major efficacy compared to ETO in reducing cell viability in HTLA-ER cells. Collectively, this 4I-based nano-formulation could represent a new promising macromolecular platform to develop a new delivery system able to increase the cytotoxicity of the anticancer drugs.

Antiproliferative Imidazo-Pyrazole-Based Hydrogel: A Promising Approach for the Development of New Treatments for PLX-Resistant Melanoma

Aiming at developing a dermal formulation against melanoma, the synthesized imidazo-pyrazoles 2-phenyl-2,3-dihydro-1H-imidazo[1,2-b]pyrazole-7-carboxylic acid (3-methoxy-4-phenoxy-benzylidene)-hydrazide (4G) and 2-phenyl-2,3-dihydro-1H-imidazo[1,2-b]pyrazole-7-carboxylic acid (4-benzyloxy-3-methoxy-benzylidene)-hydrazide (4I) were screened on patient-isolated melanoma cells (MEOV NT) and on Vemurafenib (PLX4032)-resistant (MEOV PLX-R) ones. Since 4I on MEOV PLX-R cells was 1.4-fold more effective than PLX, a hydrogel formulation containing 4I (R4HG-4I) was prepared in parallel with an empty R4-based hydrogel (R4HG) using a synthesized antibacterial resin (R4) as gelling agent. Thanks to its high hydrophilicity, porosity (85%), and excellent swelling capability (552%), R4 allowed to achieve R4HG and R4HG-4I with high equilibrium degree of swelling (EDS) and equilibrium water content (EWC). Chemometric-assisted ATR-FTIR analyses confirmed the chemical structure of swollen and fully dried (R4HG-D and R4HG-4I-D) hydrogels. The morphology of R4HG-D and R4HG-4I-D was examined by optical microscopy and SEM, while UV-vis analyses were carried out to obtain the drug loading (DL%) and the encapsulation efficiency (EE%) of R4HG-4I. Potentiometric titrations were performed to determine the equivalents of NH3+ in both R4HG and R4HG-4I. The swelling and water release profiles of both materials and related kinetics were assessed by equilibrium swelling rate and water loss studies, respectively, while their biodegradability over time was assessed by in vitro degradation experiments determining their mass loss. Rheological experiments established that both R4HG and R4HG-4I are shear-thinning Bingham pseudoplastic fluids with low yield stress, thus assuring easy spreadability in a future topical application. Release studies evidenced a sustained and quantitative release of 4I governed mainly by diffusion. Upon favorable results from further experiments in a more realistic 3D model of melanoma, R4HG-4I could represent a starting point to develop new topical therapeutic options to adjuvate the treatments of melanoma cells also when resistant to currently available drugs.

Application of curcumin nanoformulations to target folic acid receptor in cancer: Recent trends and advances

Curcumin, derived from turmeric, has a strong anticancer potential known for millennia. The development of this phytochemical as a medicine has been hampered by several significant deficiencies, including its poor water solubility and low bioavailability. This review article discusses possibilities to overcome these bottlenecks by focusing on this natural polyphenol's nanoformulation. Moreover, preparation of curcumin conjugates containing folates as ligands for folic acid receptors can add a new important dimension in this field, allowing specific targeting of cancer cells, considering the significantly higher expression of these receptors in malignant tissues compared to normal cells. It is highly expected that simultaneous improvement of different aspects of curcumin in fighting against such a complex and multifaceted disease like cancer. Therefore, we can better comprehend cancer biology by developing a mechanistic understanding of curcumin, which will also inspire the scientific community to develop new pharmacological models, and exploration of emerging directions to revitalize application of natural products in cancer therapy.

Synthesis and Evaluation of Alginate-Based Nanogels as Sustained Drug Carriers for Caffeine

The objective of this study is to design a polymeric network of nanogels for sustained release of caffeine. Therefore, alginate-based nanogels were fabricated by a free-radical polymerization technique for the sustained delivery of caffeine. Polymer alginate was crosslinked with monomer 2-acrylamido-2-methylpropanesulfonic acid by crosslinker N',N'-methylene bisacrylamide. The prepared nanogels were subjected to sol-gel fraction, polymer volume fraction, swelling, drug loading, and drug release studies. A high gel fraction was seen with the increasing feed ratio of polymer, monomer, and crosslinker. Greater swelling and drug release were observed at pH 4.6 and 7.4 as compared to pH 1.2 due to the deprotonation and protonation of functional groups of alginate and 2-acrylamido-2-methylpropanesulfonic acid. An increase was observed in swelling, loading, and release of the drug with the incorporation of a high feed ratio of polymer and monomer, while a reduction was seen with the increase in crosslinker feed ratio. Similarly, an HET-CAM test was used to evaluate the safety of the prepared nanogels, which showed that the prepared nanogels have no toxic effect on the chorioallantoic membrane of fertilized chicken eggs. Similarly, different characterizations techniques such as FTIR, DSC, SEM, and particle size analysis were carried out to determine the development, thermal stability, surface morphology, and particle size of the synthesized nanogels, respectively. Thus, we can conclude that the prepared nanogels can be used as a suitable agent for the sustained release of caffeine.

Development and evaluation of pH sensitive semi-interpenetrating networks: assessing the impact of itaconic acid and aloe vera on network swelling and cetirizine release

Hydrogels are crosslinked three-dimensional networks, and their properties can be easily tuned to target the various segments of the gastrointestinal tract (GIT). Cetirizine HCl (CTZ HCl) is an antihistaminic drug, which when given orally can upset the stomach. Moreover, this molecule has shown maximum absorption in the intestine. To address these issues, we developed a pH-responsive semi-interpenetrating polymer network (semi-IPN) for the delivery of CTZ HCl to the lower part of the GIT. Initially, 10 different formulations of itaconic acid-grafted-poly (acrylamide)/aloe vera [IA-g-poly (AAm)/aloe vera] semi-IPN were developed by varying the concentration of IA and aloe vera using the free radical polymerization technique. Based on swelling and sol-gel analysis, formulation F5 containing 0.3%w/w aloe vera and 6%w/w IA was chosen as the optimum formulation. The solid-state characterization of the optimized formulation (F5) revealed a successful incorporation of CTZ HCl in semi-IPN without any drug-destabilizing interaction. The in vitro drug release from F5 showed limited release in acidic media followed by a controlled release in the intestinal environment for over 72 h. Furthermore, during the in vivo evaluation, formulation F5 did not affect the hematological parameters, kidney, and liver functions. Clinical observations did not reveal any signs of illness in rabbits treated with hydrogels. Histopathological images of vital organs of treated animals showed normal cellular architecture. Thus, the results suggest a non-toxic nature and overall potential of the developed formulation as a targeted drug carrier.

The Dual Modification of PNIPAM and β-Cyclodextrin Grafted on Hyaluronic Acid as Self-Assembled Nanogel for Curcumin Delivery

Curcumin is an extract of turmeric (Curcuma longa) which possesses anti-inflammatory, anti-cancer and wound-healing effects and has been used as an active compound in biomedical research for many years. However, its poor solubility presents challenges for its use in drug delivery systems. A modified nanogel delivery system, with PNIPAM and β-cyclodextrin grafted onto hyaluronic acid (PNCDHA), was utilized to enhance the solubility. The polymer was characterized by NMR, and the inclusion complex between curcumin and β-cyclodextrin was confirmed by FTIR. The potential of this PNCDHA polymer complex as a drug delivery vehicle was supported by a curcumin encapsulation efficiency of 93.14 ± 5.6% and the release of encapsulated curcumin at 37 °C. At a concentration of 0.5% w/v in water, PNCDHA nanogels were biocompatible with fibroblast cell line (L929) up to a curcumin concentration of 50 µM. There was a direct concentration between curcumin loading and cellular internalization. A more detailed study of the cellular internalization of PNCDHA nanogel should be considered in order to clarify cellular delivery mechanisms and to assess how its viability as a carrier may be optimized.

Leveraging Affinity Interactions to Prolong Drug Delivery of Protein Therapeutics

While peptide and protein therapeutics have made tremendous advances in clinical treatments over the past few decades, they have been largely hindered by their ability to be effectively delivered to patients. While bolus parenteral injections have become standard clinical practice, they are insufficient to treat diseases that require sustained, local release of therapeutics. Cyclodextrin-based polymers (pCD) have been utilized as a platform to extend the local delivery of small-molecule hydrophobic drugs by leveraging hydrophobic-driven thermodynamic interactions between pCD and payload to extend its release, which has seen success both in vitro and in vivo. Herein, we proposed the novel synthesis of protein-polymer conjugates that are capped with a "high affinity" adamantane. Using bovine serum albumin as a model protein, and anti-interleukin 10 monoclonal antibodies as a functional example, we outline the synthesis of novel protein-polymer conjugates that, when coupled with cyclodextrin delivery platforms, can maintain a sustained release of up to 65 days without largely sacrificing protein structure/function which has significant clinical applications in local antibody-based treatments for immune diseases, cancers, and diabetes.