In Vitro Release of 5-Fluorouracil and Methotrexate from Different Thermosensitive Chitosan Hydrogel Systems

Preparation of PMMA-Based Temperature/pH Responsive Nanoparticles Encapsulating 5-Fluorouracil and Methotrexate In Situ by One-Pot Dispersion Photopolymerization

In order to achieve long-term and controllable release of anti-tumor drugs at specific sites, temperature/pH responsive nanoparticles encapsulating 5-fluorouracil and methotrexate in situ are prepared through dispersion photopolymerization under green LED irradiation. The physicochemical properties of nanoparticles are characterized by scanning electron microscopy, Fourier transform infrared, dynamic light scattering, thermogravimetric/differential scanning calorimetry, and X-ray diffraction. In vitro drug release at different temperatures and pH values is examined to ascertain the release pattern of two drugs, which can be well described by Korsmeyer-Peppas kinetic model. The cytotoxicity evaluation illustrates that the tumor cells could be more effectively killed by the drug-loaded nanoparticles, and the improved therapeutic effect is attributed to the controllable and sustainable drug release as well as the enhanced cellular uptake. The blood safety and good biocompatibility of nanoparticles are further confirmed by hemolysis assay, indicating the prepared nanoparticles are potential candidates for effective tumor treatment.

A Thermoresponsive injectable drug delivery system of chitosan/β-glycerophosphate with gellan gum/alginate microparticles

The development of new Drug Delivery Systems (DDS) by incorporating microparticles within hydrogels can prolong the release rate of drugs and/or other bioactive agents. In this study, we combined gellan gum/alginate microparticles within a thermoresponsive chitosan (Ch) hydrogel with β-Glycerophosphate (β-GP), designing the system to be in the sol state at 21 °C and in the gel state at 37 °C to enable the injectability of the system. The system was in the sol state between 10 °C and 21 °C. Higher concentrations of β-GP (0, 2, 3, 4, 5 w/v%) and microparticles (0, 2 and 5 w/v%) allowed a faster sol-gel transition with higher mechanical strength at 37 °C. However, the sol-gel transition was not instantaneous. The release profile of methylene blue (MB) from the microparticles was significantly affected by their incorporation in Ch/β-GP hydrogels, only allowing the release of 60-70 % of MB for 6 days, while the microparticles alone released all the MB in 48 h. The proposed system did not present cytotoxicity to VERO cell lines as a preliminary assay, with the Ch/β-GP/GG:Alg having >90 % of cellular viability. The proposed Ch/β-GP system proved to have a delaying effect on drug release and biocompatible properties, being a promising future DDS.

Research progress related to thermosensitive hydrogel dressings in wound healing: a review

Wound healing is a dynamic and complex process in which the microenvironment at the wound site plays an important role. As a common material for wound healing, dressings accelerate wound healing and prevent external wound infections. Hydrogels have become a hot topic in wound-dressing research because of their high water content, good biocompatibility, and adjustable physical and chemical properties. Intelligent hydrogel dressings have attracted considerable attention because of their excellent environmental responsiveness. As smart polymer hydrogels, thermosensitive hydrogels can respond to small temperature changes in the environment, and their special properties make them superior to other hydrogels. This review mainly focuses on the research progress in thermosensitive intelligent hydrogel dressings for wound healing. Polymers suitable for hydrogel formation and the appropriate molecular design of the hydrogel network to achieve thermosensitive hydrogel properties are discussed, followed by the application of thermosensitive hydrogels as wound dressings. We also discuss the future perspectives of thermosensitive hydrogels as wound dressings and provide systematic theoretical support for wound healing.

Injectable Hydrogels Based on Cyclodextrin/Cholesterol Inclusion Complexation and Loaded with 5-Fluorouracil/Methotrexate for Breast Cancer Treatment

Breast cancer is the second most common cancer in women worldwide. Long-term treatment with conventional chemotherapy may result in severe systemic side effects. Therefore, the localized delivery of chemotherapy helps to overcome such a problem. In this article, self-assembling hydrogels were constructed via inclusion complexation between host β-cyclodextrin polymers (8armPEG20k-CD and pβ-CD) and the guest polymers 8-armed poly(ethylene glycol) capped either with cholesterol (8armPEG20k-chol) or adamantane (8armPEG20k-Ad) and were loaded with 5-fluorouracil (5-FU) and methotrexate (MTX). The prepared hydrogels were characterized by SEM and rheological behaviors. The in vitro release of 5-FU and MTX was studied. The cytotoxicity of our modified systems was investigated against breast tumor cells (MCF-7) using an MTT assay. Additionally, the histopathological changes in breast tissues were monitored before and after their intratumor injection. The results of rheological characterization indicated the viscoelastic behavior in all cases except for 8armPEG-Ad. In vitro release results showed a variable range of release profiles from 6 to 21 days, depending on the hydrogel composition. MTT findings indicated the inhibition ability of our systems against the viability of cancer cells depending on the kind and concentration of the hydrogel and the incubation period. Moreover, the results of histopathology showed the improvement of cancer manifestation (swelling and inflammation) after intratumor injection of loaded hydrogel systems. In conclusion, the obtained results indicated the applicability of the modified hydrogels as injectable vehicles for both loading and controlled release of anticancer therapies.

5-fluorouracil-caffeic acid cocrystal delivery agent with long-term and synergistic high-performance antitumor effects

Aim: To explore how to transform cocrystals of the anticancer drug 5-fluorouracil (FL) with caffeic acid (CF; FL-CF-2H₂O) into a nanoformulation, a self-assembly strategy of cocrystal-loaded micelles is proposed. Methods: Nanomicelles were assembled to deliver cocrystal FL-CF-2H₂O with synergistic activity, and their in vitro/vivo properties were evaluated by combining theoretical and experimental methods. Result: More cocrystal was packed into the polymers due to the stronger interaction energy during micellar assembly, producing excellent cytotoxicity and pharmacokinetic behavior, especially synergistic abilities and long-term therapy. Conclusion: This case exemplifies the particular benefits of the self-assembly strategy of cocrystal-loaded micelles in keeping a delicate balance between long-term effects and high efficiency for FL, and offers a feasible technical scheme for cocrystal delivery agents for antitumor drugs.

Thermoresponsive mucoadhesive hybrid gels in advanced drug delivery systems

Thermoresponsive polymers have seen extensive use in the development of stimuli-responsive drug formulations for oral, buccal, nasal, ocular, topical, rectal, parenteral, and vaginal routes of administration. Despite their great potential, their use has been limited by various obstacles, such as undesirable high polymer concentration, wide gelation temperature, low gel strength, poor mucoadhesiveness, and short retention. Mucoadhesive polymers have been suggested to improve the mucoadhesive features of thermoresponsive gels, leading to increased drug bioavailability and efficacy. This article highlights the use of in-situ thermoresponsive mucoadhesive hydrogel blends or hybrids that have been developed and assessed in various routes of administration.

Permeability-Enhanced Liposomal Emulgel Formulation of 5-Fluorouracil for the Treatment of Skin Cancer

The plain 5-fluorouracil (5FU) formulations available in the market are associated with adverse effects such as skin irritation, pruritus, redness, blisters, allergy, and dryness on the site of application. The objective of the present study was to develop a liposomal emulgel of 5FU with increased skin permeability and efficacy using clove oil and eucalyptus oil along with pharmaceutically acceptable carriers, excipients, stabilizers, binders, and additives. A series of seven formulations were developed and evaluated for their entrapment efficiency, in vitro release profile, and cumulative drug release profile. The compatibility of drugs and excipients, as confirmed by FTIR (fourier-transform infrared spectroscopy) and DSC (differential scanning calorimetry) as well as SEM (scanning electron microscopy) and TEM (transmission electron microscopy) studies, revealed that the size and shape of liposomes are smooth and spherical, and the liposomes are non-aggregated. To understand their efficacy, the optimized formulations were evaluated for cytotoxicity using B16-F10 mouse skin melanoma cells. The eucalyptus oil and clove oil-containing preparation significantly produced a cytotoxic effect against a melanoma cell line. The addition of clove oil and eucalyptus oil increased the efficacy of the formulation by improving skin permeability and reducing the dose required for the anti-skin cancer activity.

Thermosensitive Hydrogels and Advances in Their Application in Disease Therapy

Thermosensitive hydrogels, having unique sol–gel transition properties, have recently received special research attention. These hydrogels exhibit a phase transition near body temperature. This feature is the key to their applications in human medicine. In addition, hydrogels can quickly gel at the application site with simple temperature stimulation and without additional organic solvents, cross-linking agents, or external equipment, and the loaded drugs can be retained locally to improve the local drug concentration and avoid unexpected toxicity or side effects caused by systemic administration. All of these features have led to thermosensitive hydrogels being some of the most promising and practical drug delivery systems. In this paper, we review thermosensitive hydrogel materials with biomedical application potential, including natural and synthetic materials. We describe their structural characteristics and gelation mechanism and briefly summarize the mechanism of drug release from thermosensitive hydrogels. Our focus in this review was to summarize the application of thermosensitive hydrogels in disease treatment, including the postoperative recurrence of tumors, the delivery of vaccines, the prevention of postoperative adhesions, the treatment of nervous system diseases via nasal brain targeting, wound healing, and osteoarthritis treatment.

A novel thermosensitive poloxamer-hyaluronic acid- kappa-carrageenan-based hydrogel anti-adhesive agent loaded with 5-fluorouracil: a preclinical study in Sprague-Dawley rats

Although the first-choice treatment for colorectal cancer is cytoreductive surgery combined with chemotherapy, post-surgical peritoneal adhesion and extant malignancy can cause fatal complications. Studies examining hydrogel-based postoperative anti-adhesion treatments are still limited. In this study, several formulations of 5-fluorouracil (5-FU) loaded into hyaluronic acid (HA) and kappa-carrageenan (kCGN)-poloxamer 407 (P407)-based cross-linked hydrogels were prepared and evaluated in vitro and in vivo for their efficacy in preventing adhesion. These hydrogels met a set of desired specifications such as thermosensitive behavior, strong elasticity at body temperature (tan δ < 1.0 at 37°C), and ability to encapsulate hydrophilic drug and deliver it in a sustained released manner. Our secondary purpose is to provide in situ 5-FU for additional local antitumor effect when the anti-adhesion agent is spread over the tumor site. Over 60% of the total loaded drug was released within 4 hours, and about 80% of 5-FU was released after three days. Both the Higuchi and Korsmeyer-Peppas models showed that the mechanism of sustained drug release involved diffusion. The constructed hydrogels were evaluated for in vivo intra-abdominal anti-adhesion barrier efficiency; the HA/kCGN 1%/3% w/v hydrogel formulation showed the best anti-adhesion effect in this preclinical study using Sprague-Dawley rat models.

Polymerized β-Cyclodextrin-Based Injectable Hydrogel for Sustained Release of 5-Fluorouracil/Methotrexate Mixture in Breast Cancer Management: In Vitro and In Vivo Analytical Validations

An inclusion complexation, between polymerized β-cyclodextrin and cholesterol end-capping branched polyethylene glycol, was utilized for constructing a self-assembled hydrogel. The physicochemical properties, the in vitro release profiles of 5-Fluorouracil/methotrexate (anticancer drugs), and the surface morphology of the resulting hydrogel were studied. Moreover, in vivo studies were carried out on female rats bearing breast cancer. The results revealed that the prepared systems were white in color, rubbery, and homogenous. The in vitro release studies showed an efficient ability of the modified system for drug loading and release in a sustained release manner for 14 days. The surface morphology was spongy porous. Moreover, the tumors’ healing was indicated from the analysis of tumor volume, plasma tumor markers, and histopathological analysis, compared to the controlled rats. The pharmacokinetic parameters appeared significant differences (p < 0.05) in the Cmax and Tmax of the medicated hydrogel samples, as compared with sole or combined saline-injected samples. The whole AUC of each drug in the medicated hydrogel samples was five-fold more than the mixture administrated in PBS. In conclusion, the proposed work delivered a hydrogel system that has a convenient ability for localized sustained release of breast cancer management.

Development and characterization of a novel mucoadhesive sol-gel suppository of sumatriptan: design, optimization, in vitro and ex vivo evaluation for rectal drug delivery

Aim: Sumatriptan (ST) is used for the treatment of migraine and cluster headaches. However, it exhibits low oral bioavailability (15%) due to the high first-pass metabolism. The aim of this work was to formulate an ST rectal hydrogel. Methods: Hydrogels were formulated according to a Box-Behnken design using pluronic F-127 (PF-127) and chitosan as thermogelling and mucoadhesive agents, respectively. The rectal permeability was examined using a sheep rectal mucosa. Results: Among all the formulations, the hydrogel S2 showed satisfactory drug content (4.50%), gelling temperature (32°C), pH (6.41), viscosity (105 cP) and strength (15.90 sec). Mucoadhesive strength was adequate to provide a prolonged residence time. The flux of hydrogel S2 was calculated to be 0.0003 μg/cm².min. Conclusion: The ST hydrogel can provide a potential opportunity to overcome the first pass metabolism and reduce drug dose.

Cyclodextrin/Adamantane-Grafted Polyethylene Glycol-Based Self-assembling Constructs for Topical Delivery of Ketorolac Tromethamine: Formulation, Characterization, and In Vivo Studies

Topical formulation of non-steroidal anti-inflammatory drugs (NSAIDs) exhibits many advantages over the oral administration route, such as avoiding the direct effect on GIT and avoiding the poor oral bioavailability of such drugs. Our study aims to develop a new self-assembling construct based on the hydrophobic interaction between adamantane terminated poly (ethylene glycol) polymers and polymerized β-cyclodextrin. The viscous constructs were developed from direct mixing of host and guest polymer solutions, indicating spontaneous formation without cross-linkers. The modified system was evaluated by different analyses, including X-ray diffractometry, electron microscopy, isothermal titration calorimetry, and rheological analysis. Moreover, such a system's ability for drug loading and release was investigated via the in vitro release of ketorolac tromethamine (KT) as a model of NSAIDs. Finally, the prepared formulas were applied on a rat paw edema model to prove the enhanced anti-inflammatory activities. The obtained results indicated that the modified constructs have a rubbery porous structure with an amorphous nature. Also, from rheological results, the modified system exhibited a viscous behavior with higher loss modulus (G″) compared with storage (G'). The inclusion complexation between cyclodextrin and adamantane moieties was proved by the recorded high binding constants with a 1:1 stoichiometric ratio. Furthermore, the results showed the successful KT incorporation into the modified system and quantitatively released through a semi-permeable membrane in a sustained fashion (over 24 h). Finally, the in vivo results of the medicated constructs showed a significant inhibition of the induced inflammation and swelling, indicating that the modified construct has a great utility for safe non-irritating topical delivery applications.

Development and In Vitro/In Vivo Evaluation of pH-Sensitive Polymeric Nanoparticles Loaded Hydrogel for the Management of Psoriasis

Methotrexate (MTX), the gold standard against psoriasis, poses severe problems when administered systemically viz increased toxicity, poor solubility and adverse reactions. Hence, a topical formulation of MTX for the management of psoriasis can be an effective approach. The present study aimed to develop an MTX based nanoparticle-loaded chitosan hydrogel for evaluating its potential efficacy in an imiquimod-induced psoriatic mice model. MTX-NPs loaded hydrogel was prepared and optimized using the o/w emulsion solvent evaporation method. Particle size, zeta potential, entrapment efficiency, in vitro drug release, ex vivo permeation, skin irritation and deposition studies were performed. Psoriatic Area and Severity Index (PASI) score/histopathological examinations were conducted to check the antipsoriatic potential of MTX-NPs loaded hydrogel using an imiquimod (IMQ)-induced psoriatic model. Optimized MTX-NPs showed a particle size of 256.4 ± 2.17 nm and encapsulation efficiency of 86 ± 0.03%. MTX-NPs loaded hydrogel displayed a 73 ± 1.21% sustained drug release in 48 h. Ex vivo permeation study showed only 19.95 ± 1.04 µg/cm2 of drug permeated though skin in 24 h, while epidermis retained 81.33% of the drug. A significant decrease in PASI score with improvement to normalcy of mice skin was observed. The developed MTX-NPs hydrogel displayed negligible signs of mild hyperkeratosis and parakeratosis, while histopathological studies showed healing signs of mice skin. So, the MTX-NPs loaded hydrogel can be a promising delivery system against psoriasis.

Exploring the link between chronobiology and drug delivery: effects on cancer therapy

Circadian clock is an impressive timing system responsible for the control of several metabolic, physiological and behavioural processes. Nowadays, the connection between the circadian clock and cancer occurrence and development is consensual. Therefore, the inclusion of circadian timing into cancer therapy may potentially offer a more effective and less toxic approach. This way, chronotherapy has been shown to improve cancer treatment efficacy. Despite this relevant finding, its clinical application is poorly exploited. The conception of novel anticancer drug delivery systems and the combination of chronobiology with nanotechnology may provide a powerful tool to optimize cancer therapy, instigating the incorporation of the circadian timing into clinical practice towards a more personalized drug delivery. This review focuses on the recent advances in the field of cancer chronobiology, on the link between cancer and the disruption of circadian rhythms and on the promising targeted drug nanodelivery approaches aiming the clinical application of cancer chronotherapy.

New Horizons in Hydrogels for Methotrexate Delivery

Since its first clinical application, methotrexate (MTX) has been widely used for the treatment of human diseases. Despite great advantages, some properties such as poor absorption, short plasma half-life and unpredictable bioavailability have led researchers to seek novel delivery systems to improve its characteristics for parenteral and oral administration. Recently, great attention has been directed to hydrogels for the preparation of MTX formulations. This review describes the potential of hydrogels for the formulation of MTX to treat cancer, rheumatoid arthritis, psoriasis and central nervous system diseases. We will delineate the state-of-the-art and promising potential of hydrogels for systemic MTX delivery as well as transdermal delivery of the drug-using hydrogel-based formulations.

Chemical and physical chitosan hydrogels as prospective carriers for drug delivery: a review

This review summarizes and discusses recent research progress in chemical and physical chitosan hydrogels for drug delivery.