Transport of paracetamol in swellable and relaxing polyurethane nanocomposite hydrogels

Transport Mechanism of Paracetamol (Acetaminophen) in Polyurethane Nanocomposite Hydrogel Patches-Cloisite® 30B Influence on the Drug Release and Swelling Processes

This article describes the swelling and release mechanisms of paracetamol in polyurethane nanocomposite hydrogels containing Cloisite® 30B (organically modified montmorillonite). The transport mechanism, swelling and release processes of the active substance in nanocomposite matrix were studied using gravimetric and UV-Vis spectroscopic methods. Swelling and release processes depend on the amount of clay nanoparticles in these systems and the degree of crosslinking of PU/PEG/Cloisite® 30B hydrogel nanocomposites. The presence of clay causes, on the one hand, a reduction in free volumes in the polymer matrices, making the swelling process less effective; on the other hand, the high swelling and self-aggregation behavior of Cloisite® 30B and the interactions of paracetamol both with it and with the matrix, cause a change in the transport mechanism from anomalous diffusion to Fickian-like diffusion. A more insightful interpretation of the swelling and release profiles of the active substance was proposed, taking into account the "double swelling" process, barrier effect, and aggregation of clay. It was also proven that in the case of modification of polymer matrices with nanoparticles, the appropriate selection of their concentration is crucial, due to the potential possibility of controlling the swelling and release processes in drug delivery patches.

Temperature-Sensitive Hydrogels as Carriers for Modulated Delivery of Acetaminophen

The purposes of this study are the polymerization of temperature-sensitive copolymers based on N-isopropyl acrylamide and 10 mol % of 2-hydroxypropylmethacrylate, characterisations of their thermal, morphological and swelling properties, as well as the analysis of potential application in drug-delivery systems. Acetaminophen, the representative of non-steroidal anti-inflammatory drugs, was used as a model drug in this study. It is a common pain relief drug, which is also used for fever treatment. However, oral administration comes with certain health risks, mainly the overdose and frequent administration of up to four times a day. The goal of applying temperature-sensitive hydrogel is to enable extended administration once a day, depending on the body temperature. The swelling behavior of the obtained poly(N-isopropyl acrylamide-co-2-hydroxypropylmethacrylate) (p(NIPA/HPMA)) hydrogels and their temperature-sensitivity, kinetics and order of swelling processes at 18 and 38 °C were analyzed. The thermal properties of these hydrogels were observed by the DSC method, and the obtained thermograms showed both melting and glass transitions. The drug delivery system of p(NIPA/HPMA) hydrogels with loaded acetaminophen was analyzed using scanning electron microscopy and Fourier transform infrared spectroscopy methods. Structural analysis of FTIR spectra indicates that non-covalent intermolecular interactions of the type of hydrogen bonds were formed among functional groups of acetaminophen and side-chains of p(NIPA/HPMA) hydrogels. The surface structure of p(NIPA/HPMA) hydrogels after drug loading indicates the acetaminophen presence into the pores of the hydrogel network, and their loading efficiency was higher than 92%. Qualitative and quantitative analysis of acetaminophen, determined by the high-pressure liquid chromatography method, showed that about 90-99% of the loaded amount was released from p(NIPA/HPMA) hydrogels within 24 h. Kinetic parameters of the acetaminophen release under simulated gastrointestinal conditions were determined. Based on obtained results, the drug delivery system of temperature-sensitive p(NIPA/HPMA) hydrogels with loaded acetaminophen could be suitable for additional investigation for modulated drug administration, e.g., for extended drug administration.

Nafcillin-Loaded Photocrosslinkable Nanocomposite Hydrogels for Biomedical Applications

Skin infections are frequently treated via intravenous or oral administration of antibiotics, which can lead to serious adverse effects and may sometimes contribute to the proliferation of resistant bacterial strains. Skin represents a convenient pathway for delivering therapeutic compounds, ensured by the high number of blood vessels and amount of lymphatic fluids in the cutaneous tissues, which are systematically connected to the rest of the body. This study provides a novel, straightforward method to obtain nafcillin-loaded photocrosslinkable nanocomposite hydrogels and demonstrates their performance as drug carriers and antimicrobial efficacy against Gram-positive bacteria. The novel formulations obtained, based on polyvinylpyrrolidone, tri(ethylene glycol) divinyl ether crosslinker, hydrophilic bentonite nanoclay, and/or two types of photoactive (TiO₂ and ZnO) nanofillers, were characterized using various analytical methods (transmission electron microscopy (TEM), scanning electron microscopy-energy-dispersive X-ray analysis (SEM-EDX), mechanical tests (tension, compression, and shear), ultraviolet-visible spectroscopy (UV-Vis), swelling investigations, and via specific microbiological assays ("agar disc diffusion method" and "time-kill test"). The results reveal that the nanocomposite hydrogel possessed high mechanical resistance, good swelling abilities, and good antimicrobial activity, demonstrating a decrease in the bacteria growth between 3log₁₀ and 2log₁₀ after one hour of direct contact with S. aureus.

Insight into the release mechanisms of diflunisal and salicylic acid from poly(vinyl alcohol). The role of hydrogen bonding interactions

Diflunisal (5-(2,4-Difluorophenyl)salicylic acid, DIF), salicylic acid (SAL) derivative, which, on the one hand, is active pharmaceutical ingredient, on the other hand, belongs to the compounds exhibiting excited-state intramolecular proton transfer (ESIPT) behaviour was used to study the drug interactions with poly(vinyl alcohol) (PVA) matrix. For clarifying the nature and mechanisms of the drug-matrix interactions the salicylic acid (SAL) molecule was selected as the model active ESIPT compound, whose physicochemical properties in different media are well understood. The solute-solvent interactions (non-specific (dipole-dipole) versus specific (hydrogen bonding)) of DIF and SAL with different neat solvents were investigated using the steady-state spectroscopic technique. The solvent effect on spectral behaviours of DIF and SAL was analyzed based on the parametric solvent scales. In order to identify functional groups in the PVA matrices, determine the structure present in the studied molecule-PVA system and thus obtain information about the potential interactions between PVA and the studied molecules, the Raman spectra of pure PVA, SAL-PVA and DIF-PVA systems were measured. It has been shown that the molecular structure of the active substance entrapped in the polymer matrix affects the structure of the polymer, i.e., isotactic (SAL-PVA) versus syndiotactic (DIF-PVA) structure. The analysis of drug release kinetics revealed that the DIF is more strongly bound to PVA in comparison to SAL, which confirms conclusions drawn from the analysis of the Raman spectra i.e., the isotactic structure of SAL-PVA material results in a faster initial release process of weakly bound, located on the surface of the polymer SAL molecules.

Biomedical Applications of Polyurethane Hydrogels, Polyurethane Aerogels and Polyurethane-Graphene Nanocomposite Materials

BACKGROUND

Increasing new emerging ill-healths have posed therapeutic challenges in modern medicine. Hence polyurethane hydrogels that comprise polyol, copolymer and extender could be prepared from diverse chemical compounds with adjuvants such as ascorbic acid, sorbitol among others. Their mechano-physicochemical properties are functions of their biological activities. Therefore there is need to assess their therapeutic potentials.

METHODS

literature were searched on synthesis and medical uses of polyurethane - hydrogels, polyurethane - aerogels and polyurethane - graphene nanocomposite materials, with a view to identifying their sources, synthesis, mechanical and physiochemical properties, biomedical applications, chirality, and the relevance of Lipinski's rule of five in the synthesis of oral polyurethane nanocomposite materials.

RESULTS

The prepared hydrogels and aerogels could be used as polymer carriers for intradermal, cutaneous and intranasal drugs. They can be fabricated and used as prosthetics. In addition the strength modulus (tensile stress-tensile strain ratio), biodegradability, biocompatibility and non-toxic effects of the polyurethane hydrogels and aerogels are the highly desirable properties. However, body and environmental temperatures may contribute to their instability, hence there is need to improve on the synthesis of aerogels and hydrogels of polyurethane that can last for many years. Alcoholism, diabetes, pyrogenic diseases, mechanical and physical forces, and physiological variability may also reduce the life span of polyurethane aerogels and hydrogels.

CONCLUSION

Synthesis of polyurethane hydrogel-aerogel complex that can be used in complex, rare biomedical cases is of paramount importance. These hydrogels and aerogels may be hydrophobic, hydrophilic, aerophobic-aerophilic or amphiphilic and sometimes lipophilic depending on structural components and the intended biomedical uses. Polyurethane graphene nanocomposite materials are used in the treatment of a myriad of diseases including cancer and bacterial infection.

Synthesis And Evaluation of Polyethylene Glycol-4000-Co-Poly (AMPS) Based Hydrogel Membranes for Controlled Release of Mupirocin for Efficient Wound Healing

BACKGROUND

Chronic wound healing is a major challenge for health care system around the globe. Current study was conducted to develop and characterize chemically cross-linked polyethylene glycol-co-poly (AMPS) hydrogel membranes to enhanced the wound healing efficiency of antibiotic mupirocin (MP).

METHODS

Free radical polymerization technique was used for the development of hydrogel membranes. In aqueous medium, polymer PEG-4000 cross-linked with the monomer 2-acrylamido-2-methylpropane sulfonic acid (AMPS) in the presence of initiators ammonium peroxide sulfate (APS) and sodium hydrogen sulfite (SHS). N, N-Methylenebisacrylamide (MBA) was used as cross-linker in the preparation of hydrogel membranes. Developed membranes were spherical, transparent, and elastic. FTIR, TGA/DSC, and SEM were used to characterize the polymeric system. Swelling behavior, drug loading, and its release pattern at pH of 5.5 and 7.4, irritation study, ex vivo drug permeation, and deposition study was also evaluated.

RESULTS

Formed membranes were spherical, transparent and elastic. The formation of a stable polymeric network was confirmed by structural and thermal analysis. Permeation of the drug its deposition in the skin showed good permeation and retention. No irritancy to the skin was observed.

CONCLUSION

On the basis of results obtained, the present study concluded that it may be an ideal network for the delivery of mupirocin in skin infections.

The Role of Hydrogen Bonding in Paracetamol-Solvent and Paracetamol-Hydrogel Matrix Interactions

The photophysical and photochemical properties of antipyretic drug - paracetamol (PAR) and its two analogs with different substituents (acetanilide (ACT) and N-ethylaniline (NEA)) in 14 solvents of different polarity were investigated by the use of steady-state spectroscopic technique and quantum-chemical calculations. As expected, the results show that the spectroscopic behavior of PAR, ACT, and NEA is highly dependent on the nature of the solute-solvent interactions (non-specific (dipole-dipole) and specific (hydrogen bonding)). To characterize these interactions, the multiparameter regression analysis proposed by Catalán was used. In order to obtain a deeper insight into the electronic and optical properties of the studied molecules, the difference of the dipole moments of a molecule in the ground and excited state were determined using the theory proposed by Lippert, Mataga, McRae, Bakhshiev, Bilot, and Kawski. Additionally, the influence of the solute polarizability on the determined dipole moments was discussed. The results of the solvatochromic studies were related to the observations of the release kinetics of PAR, ACT, and NEA from polyurethane hydrogels. The release kinetics was analyzed using the Korsmayer-Peppas and Hopfenberg models. Finally, the influence of the functional groups of the investigated compounds on the release time from the hydrogel matrix was analyzed.