A Novel Approach of Polyvinyl Alcohol/Acrylic Acid Based Hydrogels for Controlled Delivery of Diclofenac Sodium

AIM AND OBJECTIVE

The aim of this study was to prepare polyvinyl alcohol/acrylic acid (PVA/AA) hydrogels for the controlled release of diclofenac sodium and to develop PVA/AA hydrogels as controlled release carriers to overcome not only the side effects of diclofenac sodium but also sustain its release for an extended period.

BACKGROUND

Diclofenac sodium is employed for relieving pain and fever. The half-life of diclofenac sodium is very short (1-2 h). Hence, multiple intakes of diclofenac sodium are required to maintain a constant pharmacological action. Multiple GI adverse effects are produced as a result of diclofenac sodium intake.

METHOD

A free radical polymerization technique was used for crosslinking PVA with AA in the presence of APS. EGDMA was used as a cross-linker. FTIR and XRD confirmed the preparation and loading of the drug by prepared hydrogels. An increase in the thermal stability of PVA was shown by TGA and DSC analysis. Surface morphology was investigated by SEM. Similarly, water penetration and drug loading were demonstrated by porosity and drug loading studies. The pH-sensitive nature of PVA/AA hydrogels was investigated at different pH values by swelling and drug release studies.

RESULTS

The development and drug loading of PVA/AA hydrogels were confirmed by FTIR and XRD analysis. TGA and DSC indicated high thermal stability of prepared hydrogels as compared to unreacted PVA. SEM indicated a hard and compact network of developed hydrogels. The swelling and drug release studies indicated maximum swelling and drug release at high pH as compared to low pH values, indicating the pH-sensitive nature of prepared hydrogels. Moreover, we demonstrated that drug release was sustained for a prolonged time in a controlled pattern by prepared hydrogels by comparing the drug release of the developed hydrogels with the commercial product Cataflam.

CONCLUSION

The results indicated that prepared PVA/AA hydrogels can be used as an alternative approach for the controlled delivery of diclofenac sodium.

Old drug, new tricks: polymer-based nanoscale systems for effective cytarabine delivery

Cytarabine, an antimetabolite antineoplastic agent, has been utilized to treat various cancers. However, because of its short half-life, low stability, and limited bioavailability, achieving an optimal plasma concentration requires continuous intravenous administration, which can lead to toxicity in normal cells and tissues. Addressing these limitations is crucial to optimize the therapeutic efficacy of cytarabine while minimizing its adverse effects. The use of novel drug delivery systems, such as polymer-based nanocarriers have emerged as promising vehicles for targeted drug delivery due to their unique properties, including high stability, biocompatibility, and tunable release kinetics. In this review, we examine the application of various polymer-based nanocarriers, including polymeric nanoparticles, polymeric micelles, dendrimers, polymer-drug conjugates, and nano-hydrogels, for the delivery of cytarabine. The article highlights the limitations of conventional cytarabine administration which often lead to suboptimal therapeutic outcomes and systemic toxicity. The rationale for using polymer-based nanocarriers is discussed, highlighting their ability to overcome challenges by providing controlled drug release, improved stability, and enhanced targeting capabilities. In summary, this review offers a valuable resource for drug delivery scientists by providing insights into the design principles, formulation strategies, and potential applications of polymer-based nanocarriers that can enhance the therapeutic efficacy of cytarabine.

Flexible Topical Hydrogel Patch Loaded with Antimicrobial Drug for Accelerated Wound Healing

A hydrogel topical patch of neomycin was developed by using sodium alginate (SA) and hydroxyethylcellulose (HEC) as polymers. Free radical polymerization in an aqueous medium was initiated by using acrylic acid (AA) and N,N'-methylenebisacrylamide (MBA). Prepared hydrogels were characterized for pH sensitivity and sol-gel analysis. In addition, the effect of reactant contents on the developed formulation was evaluated by swelling behavior. SEM assay showed the rough structure of the hydrogel-based polymeric matrix, which directly enhances the ability to uptake fluid. FTIR spectra revealed the formation of a new polymeric network between reactant contents. TGA and DSC verified that fabricated polymeric patches were more thermodynamically stable than pure components. Gel fractions increased with increases in polymer, monomer, and cross-linker contents. The swelling study showed the pH-dependent swelling behavior of patches at pH 5.5, 6.5, and 7.4. The release pattern of the drug followed zero-order kinetics, with diffusion-controlled drug release patterns according to the Korsmeyer-Peppas (KP) model. Ex vivo studies across excised rabbit skin verified the drug retention in the skin layers. The hydrogel patch effectively healed the wounds produced on the rabbit skin, whereas the formulation showed no sign of irritation on intact skin. Therefore, neomycin hydrogel patches can be a potential candidate for controlled delivery for efficient wound healing.

Formulation of pH-responsive highly swellable hydrogel scaffolds for controlled release of tramadol HCl: characterization and biocompatibility evaluation

Introduction: The objective of current project was to formulate a system for controlled delivery of Tramadol HCl (TRD), an opioid analgesic used in the treatment of moderate to severe pain. Methods: For this purpose, a pH responsive AvT-co-poly hydrogel network was formulated through free radical polymerization by incorporating natural polymers i.e., aloe vera gel and tamarind gum, monomer and crosslinker. Formulated hydrogels were loaded with Tramadol HCl (TRD) and evaluated for percent drug loading, sol-gel fraction, dynamic and equilibrium swelling, morphological characteristics, structural features and in-vitro release of Tramadol HCl. Results and Discussions: Hydrogels were proved to be pH sensitive as remarkable dynamic swelling response ranging within 2.94g/g-10.81g/g was noticed at pH 7.4 as compared to pH 1.2. Percent drug loading was in the range of 70.28%-90.64% for all formulations. Thermal stability and compatibility of hydrogel components were validated by DSC analysis and FTIR spectroscopy. Controlled release pattern of Tramadol HCl from the polymeric network was confirmed as maximum release of 92.22% was observed for over a period of 24 hours at pH 7.4. Moreover, oral toxicity studies were also conducted in rabbits to investigate the safety of hydrogels. No evidence of any toxicity, lesions and degeneration was reported, confirming the biocompatibility and safety of grafted system.

Formulation and Characterization of Polymeric Cross-Linked Hydrogel Patches for Topical Delivery of Antibiotic for Healing Wound Infections

Wound healing faces significant challenges in clinical settings. It often contains a series of dynamic and complex physiological healing processes. Instead of creams, ointments and solutions, alternative treatment approaches are needed. The main objective of the study was to formulate bacitracin zinc-loaded topical patches as a new therapeutic agent for potential wound healing. A free radical polymerization technique was optimized for synthesis. Polyethylene glycol-8000 (PEG-8000) was chemically cross-linked with acrylic acid in aqueous medium, using Carbopol 934 as a permeation enhancer and tween 80 as surfactant. Ammonium persulfate and N,N’-Methylenebisacrylamide (MBA) were utilized as initiator and cross-linker. FTIR, DSC, TGA, and SEM were performed, and patches were evaluated for swelling dynamics, sol-gel analysis, in vitro drug release in various media. A Franz diffusion cell was used for the permeation study. Irritation and wound healing with the drug-loaded patches were also studied. The characterization studies confirmed the formation of a cross-linked hydrogel network. The highest swelling and drug release were observed in formulations containing highest Polyethylene glycol-8000 and lowest N,N’-Methylenebisacrylamide concentrations. The pH-sensitive behavior of patches was also confirmed as more swelling, drug release and drug permeation across skin were observed at pH 7.4. Fabricated patches showed no sign of irritation or erythema as evaluated by the Draize scale. Faster wound healing was also observed with fabricated patches compared to marketed formulations. Therefore, such a polymeric network can be a promising technology for speeding up wound healing and minor skin injuries through enhanced drug deposition.

Designing of SiO2 mesoporous nanoparticles loaded with mometasone furoate for potential nasal drug delivery: Ex vivo evaluation and determination of pro-inflammatory interferon and interleukin mRNA expression

The main objective of the current research work was to synthesize mesoporous silica nanoparticles for controlled delivery of mometasone furoate for potential nasal delivery. The optimized sol-gel method was used for the synthesis of mesoporous silica nanoparticles. Synthesized nanoparticles were processed through Zeta sizer, SEM, TEM, FTIR, TGA, DSC, XRD, and BET analysis for structural characterization. The in vitro dissolution test was performed for the inclusion compound, while the Franz diffusion experiment was performed for permeability of formulation. For the determination of expression levels of anti-inflammatory cytokines IL-4 and IL-5, RNA extraction, reverse transcription, and polymerase chain reaction (RT-PCR) were performed. The MTT assay was also performed to determine cell viability. Synthesized and functionalized mesoporous silica nanoparticles showed controlled release of drugs. FT-IR spectroscopy confirmed the presence of the corresponding functional groups of drugs within mesoporous silica nanoparticles. Zeta sizer and thermal analysis confirmed the delivery system was in nano size and thermally stable. Moreover, a highly porous system was observed during SEM and TEM evaluation, and further it was confirmed by BET analysis. Greater cellular uptake with improved permeability characteristics was also observed. As compared to the crystalline drug, a significant improvement in the dissolution rate was observed. It was concluded that stable mesoporous silica nanoparticles with significant porosity were synthesized, efficiently delivering the loaded drug without any toxic effect.

Fabrication of pH responsive hydrogel blends of chondroitin sulfate/pluronic F-127 for the controlled release of ketorolac: its characterization and acute oral toxicity study

OBJECTIVE

Ketorolac tromethamine (KT), selected as a model drug, is used in management of moderate to severe acute pain. It has a short half-life (∼5.5 h) and requires frequent dose administration when needed for longer period of time. In our current project, we designed pH responsive hydrogel blends of chondroitin sulfate/pluronic F-127 (CS/Pl) for the controlled release of ketorolac.

METHODS

Hydrogel blends were fabricated using free radical polymerization reaction technique utilizing different ratios of chondroitin sulfate (CS) (polymer) and pluronic F-127 (polymer), acrylic acid (monomer), N,N'-methyl-bisacrylamide (MBA) (cross-linker), initiator ammonium persulfate (APS) and tween-80 (surfactant). The fabricated hydrogel blends were studied and evaluated for pH responsiveness, swelling, water absorbency, in vitro drug release, and morphological characteristics such as SEM, XRD, FTIR, and TGA/DSC. Acute toxicity study was performed on rabbits.

RESULTS

Maximum swelling and water absorbency were shown by CS/Pl blends being significantly greater at 7.4 (basic pH) than in 1.2 (acidic pH). In vitro dissolution demonstrated pH responsive controlled KT release following zero order at higher pH (7.4) medium up to 36 h. FTIR studies confirmed the structures of our blends; SEM results showed porous framework; thermal studies revealed higher stability of hydrogels than the individual polymers; and XRD confirmed the nature of our blends. Toxicity study revealed the nontoxic nature of the hydrogel blends.

CONCLUSION

The prepared CS/Pl hydrogels demonstrated stimuli-controlled release with delivery of drug for prolonged period of time and thus can minimize dosing frequency, safe drug delivery, increased patient compliance and easiness.

Polyvinylpyrrolidone K-30-Based Crosslinked Fast Swelling Nanogels: An Impeccable Approach for Drug's Solubility Improvement

Poor solubility is a global issue of copious pharmaceutical industries as large number of drugs in development stage as well as already marketed products are poorly soluble which results in low dissolution and ultimately dosage increase. Current study is aimed at developing a polyvinylpyrrolidone- (PVP-K30-) based nanogel delivery system for solubility enhancement of poorly soluble drug olanzapine (OLP), as solubilization enhancement is the most noteworthy application of nanosystems. Crosslinking polymerization with subsequent condensation technique was used for the synthesis of nanogels, a highly responsive polymeric networks in drug's solubility. Developed nanogels were characterized by percent entrapment efficiency, sol-gel, percent swelling, percent drug loaded content (%DLC), percent porosity, stability, solubility, in vitro dissolution studies, FTIR, XRD, and SEM analysis. Furthermore, cytotoxicity study was conducted on rabbits to check the biocompatibility of the system. Particle size of nanogels was found with 178.99 ± 15.32 nm, and in vitro dissolution study exhibited that drug release properties were considerably enhanced as compared to the marketed formulation OLANZIA. The solubility studies indicated that solubility of OLP was noticeably improved up to 36.7-fold in phosphate buffer of pH 6.8. In vivo cytotoxicity study indicated that prepared PVP-K30-based formulation was biocompatible. On the basis of results obtained, the developed PVP-K30-co-poly (AMPS) nanogel delivery system is expected to be safe, effective, and cost-effective for solubility improvement of poorly soluble drugs.

Synthesis of novel combinatorial drug delivery system (nCDDS) for co-delivery of 5-Fluorouracil and Leucovorin calcium for colon targeting and controlled drug release

Objective: Purpose of the current study was to improve the oral effectiveness of 5-Fluorouracil (5-FU) by developing novel controlled, combinatorial drug delivery system (nCDDS) for co-delivery of 5-FU and Leucovorin (LC) for colon targeting.Significance: on the basis of results obtained, novel controlled, combinatorial drug delivery system (nCDDS) could be an effective strategy for the colon targeting of 5-FU and LC.Methods: Free radical polymerization method was tuned and used to fabricate this nCDDS. The nCDDS is synthesized in two steps, firstly synthesis of 5-fluoruracil/leucovorin calcium loaded nanogels and secondly, pre-synthesized 5-FU & LC loaded nanogels were dispersed in pectin based polymerized matrix hard gel. The nanogels and nCDD gels were characterized for network structure, thermal stability and surface morphology. Swelling and in-vitro release studies were carried out at different pH 1.2 and 7.4 both for naive nanogels and combined matrix gels. In-vivo study of combinatorial gel was performed on rabbits by using HPLC method to estimate plasma drug concentration and pharmacokinetics parameters.Results: Structure and thermal analysis confirmed the formation of stable polymeric network. SEM of nanogels and combinatorial gels showed that the spongy and rough edges particles and uniformly distributed in the combinatorial gel. The prepared nCDDS showed excellent water loving capacity and pH responsiveness. Combinatorial gel showed excellent characteristic for colonic delivery of drugs, which were confirmed by various in-vitro and in-vivo characterization. Acute oral toxicity study of combinatorial gel confirmed the biocompatible and non-toxic characteristics of developed formulation.Conclusion: Conclusively it can be found that nCDDS showed excellent properties regarding drug targeting in a controllable manner as compared to naive PEGylated nanogels.

Overview of nanoparticulate strategies for solubility enhancement of poorly soluble drugs

Poor aqueous solubility and poor bioavailability are major issues with many pharmaceutical industries. By some estimation, 70-90% drug candidates in development stage while up-to 40% of the marketed products are poorly soluble which leads to low bioavailability, reduced therapeutic effects and dosage escalation. That's why solubility is an important factor to consider during design and manufacturing of the pharmaceutical products. To-date, various strategies have been explored to tackle the issue of poor solubility. This review article focuses the updated overview of commonly used macro and nano drug delivery systems and techniques such as micronization, solid dispersion (SD), supercritical fluid (SCF), hydrotropy, co-solvency, micellar solubilization, cryogenic technique, inclusion complex formation-based techniques, nanosuspension, solid lipid nanoparticles, and nanogels/nanomatrices explored for solubility enhancement of poorly soluble drugs. Among various techniques, nanomatrices were found a promising and impeccable strategy for solubility enhancement of poorly soluble drugs. This article also describes the mechanism of action of each technique used in solubilization enhancement.

Micro and nanorobot-based drug delivery: an overview

Progress in the drug delivery system in the last few decades has led to many advancements for efficient drug delivery. Both micro and nanorobots, are regarded as superior drug delivery systems to deliver drugs efficiently by altering other forms of energy into propulsion and movements. Furthermore, it can be advantageous as it is directed to targeted sites beneath physiological environments and conditions. They have been validated to possess the capability to encapsulate, transport, and supply therapeutic contents directly to the disease sites, thus enhancing the therapeutic efficiency and decreasing systemic side effects of the toxic drugs. This review discusses about the microand nanorobots for the diagnostics and management of diseases, types of micro, and nanorobots, role of robots in drug delivery, and its biomedical applications.

Synthesis of PEG-4000-co-poly (AMPS) nanogels by cross-linking polymerization as highly responsive networks for enhancement in meloxicam solubility

Poor solubility is an ongoing issue and the graph of poorly soluble drugs has increased markedly which critically affect their dissolution, bioavailability, and clinical effects. This common issue needs to be addressed, for this purpose a series of polyethylene glycol (PEG-4000) based nanogels were developed by free radical polymerization technique to enhance the solubility, dissolution, and bioavailability of poorly soluble drug meloxicam (MLX), as improved solubility is the significant application of nanosystems. Developed nanogels formulations were characterized by FTIR, XRD, SEM, zeta sizer, percent equilibrium swelling, drug loaded content (DLC), drug entrapment efficiency (DEE), solubility studies, and in vitro dissolution studies. Furthermore, cytotoxicity studies were conducted in order to determine the bio-compatibility of the nanogels drug delivery system to biological environment. Nanogels particle size was found to be 156.19 ± 09.33 d.nm. Solubility study confirmed that the solubility of poorly soluble drug MLX was significantly enhanced up to 36 folds as compared to reference product (Mobic^®). The toxicity study conducted on rabbits and MTT assay endorsed the safety of the developed nanogels formulations to the biological system.

Porous and highly responsive cross-linked β-cyclodextrin based nanomatrices for improvement in drug dissolution and absorption

AIMS

Aim of the study was to enhance the solubility of Chlorthalidone by developing beta-cyclodextrin cross-linked hydrophilic nanomatrices.

MAIN METHODS

Nine different formulations were fabricated by free radical polymerization technique. All formulations were characterized through different studies. FTIR spectroscopy of unloaded and loaded nanomatrices was processed to determine compatibility of constituents and that of the drug with the system. Surface morphology of the nanomatrices was studied by SEM. The size of the optimized formulation was determined by zeta sizer. Swelling, in-vitro release and solubility studies were carried out in different media and results of in-vitro release profiles of nanomatrices and commercially available tablet of Chlorthalidone were compared. For determination of biocompatibility, toxicity studies were proclaimed in rabbits.

KEY FINDINGS

Main peaks of corresponding functional groups of individual constituents and that of drug were depicted in FTIR spectra of unloaded and loaded nanomatrices. Porous and fluffy structure was visualized through SEM images. Particle size of the optimized formulation was in the range of 175 ± 5.27 nm. Percent loading of optimized formulation showed the best result. Comparing the in-vitro drug release profiles of nanomatrices and commercially available tablet, the results of the synthesized nanomatrices were quite satisfactory. Solubility profiles were also high as compared to the drug alone. Moreover, toxicity studies confirmed that nanomatrices were biocompatible and no sign of any toxic effect was found.

SIGNIFICANCE

We concluded that our developed nanomatrices had successfully enhanced the solubility of Chlorthalidone and can also be used for other poorly aqueous soluble drugs.

pH/Thermo-Dual Responsive Tunable In Situ Cross-Linkable Depot Injectable Hydrogels Based on Poly(N-Isopropylacrylamide)/Carboxymethyl Chitosan with Potential of Controlled Localized and Systemic Drug Delivery

In the current study, cytocompatible in situ cross-linkable pH/thermo-dual responsive injectable hydrogels were prepared based on poly(N-isopropylacrylamide) and carboxymethyl chitosan, i.e., poly(CMCS-g-NIPAAm). The prepared formulations were aimed to be used as drug depot of 5-fluorouracil (5-FU) after subcutaneous administration in vivo. The phase transition from sol-gel state under physiologic temperature range was analyzed and confirmed by tube titling and optical transmittance measurements. The viscoelastic properties of gel formulations were confirmed by rheology determination via time sweep, temperature, and continuous ramp test. Oscillatory swelling cycles confirmed temperature effect and structural changes. pH and temperature sensitivity of dual responsive gels were analyzed at different pH and temperature programs. In vitro drug release profile displayed that developed formulations have the highest release in acidic pH at 25°C. The safety of blank gel formulations was evaluated against L929 cell lines via MTT assay and confirmed cytocompatibility with no detectable toxicity. In vitro cytotoxic potential of drug-loaded gels against HeLa and MCF-7 cancer cell lines confirmed that 5-FU has controlled cytotoxic potential in depot form in comparison to free 5-FU solution. The IC₅₀ values for free 5-FU (21 ± 05 μg/ml and 18 ± 66 μg/ml) were found higher in comparison to the loaded form. The copolymer structure formation was confirmed by NMR and FTIR spectroscopic analysis. TG and DSC analysis proved the thermal stability and phase transition temperatures of pure and copolymer samples, while SEM analysis showed the porous nature of in situ formed hydrogels. It was concluded from the results that the developed formulations have pH/temperature sensitivity with potential of systemic and intratumoral controlled drug delivery properties.

Preparation and Evaluation of Skin Wound Healing Chitosan-Based Hydrogel Membranes

The purpose of the study was to synthesize and characterize a new form of topical membranes as chitosan-based hydrogel membranes for bacterial skin infections. The polymeric membranes were synthesized by modification in free radical solution polymerization technique. High molecular weight (HMW) chitosan polymer was cross-linked with monomer 2-acrylamido-2-methylpropane sulfonic acid (AMPS) through cross-linker N,N-methylenebisacrylamide (MBA). Mupirocin, an antibiotic, was used as model drug. The polymeric membranes were prepared in spherical form that found stable and elastic. Characterization of hydrogel membranes was performed by FTIR, SEM, DSC, TGA, swelling behavior, drug release, irritation study, and ex vivo drug permeation and deposition study. Structural and thermal studies confirmed the formation of new polymeric network with enhanced stability of hydrogel membranes. Permeation flux of drug from optimized formulation through rabbit's skin assessed by using Franz cell was up to 104.09 μg cm^-2 h^-1. Furthermore, hydrogel membrane has significant retention of drug in skin up to 2185 μg 1.5 cm^-2. Draize patch test confirmed the synthesized hydrogels as non-irritant to skin. The preparation of a topical membrane with improved antibacterial activity within controlled release manner is desirable for the advancement and treatment of skin diseases.

Non-invasive strategies for targeting the posterior segment of eye

The safe and effective treatment of eye diseases has been remained a global myth. Several advancements have been done and various drug delivery and treatment techniques have been suggested. The Posterior segment disorders are the leading cause of visual impairments and blindness. Targeting the therapeutic agents to the anterior and posterior segments of the eye has attracted extensive attention from the scientific community. Significant key factors in the success of ocular therapy are the development of safe, effective, economic and non-invasive novel drug delivery systems. These specialized non-invasive ocular drug delivery systems revolutionized the drug delivery strategies by overcoming the limitations, provided targeted delivery to the ocular tissues by avoiding larger doses, and reducing the toxicity encountered by the conventional approaches. These non-invasive systems are fabricated by ingredients encompassing biodegradability, biocompatibility, mucoadhesion, solubility and permeability enhancement and stimuli responsiveness. The variety of routes are utilized to provide minimally invasive drug delivery to the patients without any discomfort and pain. This review is focused on the brief introduction, types, significance, preparation techniques, components and mechanism of drug release of non-invasive systems, including in situ gelling systems, microspheres, iontophoresis, nanoparticles, nanosuspensions and specialized novel emulsions.