Preparation, characterization andin vitrorelease properties of ibuprofen-loaded microspheres based on polylactide, poly(϶-caprolactone) and their copolymers

Unleashing the healing potential: Exploring next-generation regenerative protein nanoscaffolds for burn wound recovery

Burn injury is a serious public health problem and scientists are continuously aiming to develop promising biomimetic dressings for effective burn wound management. In this study, a greater efficacy in burn wound healing and the associated mechanisms of α-lactalbumin (ALA) based electrospun nanofibrous scaffolds (ENs) as compared to other regenerative protein scaffolds were established. Bovine serum albumin (BSA), collagen type I (COL), lysozyme (LZM) and ALA were separately blended with poly(ε-caprolactone) (PCL) to fabricate four different composite ENs (LZM/PCL, BSA/PCL, COL/PCL and ALA/PCL ENs). The hydrophilic composite scaffolds exhibited an enhanced wettability and variable mechanical properties. The ALA/PCL ENs demonstrated higher levels of fibroblast proliferation and adhesion than the other composite ENs. As compared to PCL ENs and other composite scaffolds, the ALA/PCL ENs also promoted a better maturity of the regenerative skin tissues and showed a comparable wound healing effect to Collagen spongeⓇ on third-degree burn model. The enhanced wound healing activity of ALA/PCL ENs compared to other ENs could be attributed to their ability to promote serotonin production at wound sites. Collectively, this investigation demonstrated that ALA is a unique protein with a greater potential for burn wound healing as compared to other regenerative proteins when loaded in the nanofibrous scaffolds.

Advancing PHBV Biomedical Potential with the Incorporation of Bacterial Biopigment Prodigiosin

The quest for sustainable biomaterials with excellent biocompatibility and tailorable properties has put polyhydroxyalkanoates (PHAs) into the research spotlight. However, high production costs and the lack of bioactivity limit their market penetration. To address this, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was combined with a bacterial pigment with strong anticancer activity, prodigiosin (PG), to obtain functionally enhanced PHBV-based biomaterials. The samples were produced in the form of films 115.6-118.8 µm in thickness using the solvent casting method. The effects of PG incorporation on the physical properties (morphology, biopolymer crystallinity and thermal stability) and functionality of the obtained biomaterials were investigated. PG has acted as a nucleating agent, in turn affecting the degree of crystallinity, thermal stability and morphology of the films. All samples with PG had a more organized internal structure and higher melting and degradation temperatures. The calculated degree of crystallinity of the PHBV copolymer was 53%, while the PG1, PG3 and PG3 films had values of 64.0%, 63.9% and 69.2%, respectively. Cytotoxicity studies have shown the excellent anticancer activity of films against HCT116 (colon cancer) cells, thus advancing PHBV biomedical application potential.

In Vitro Evaluation of Smart and pH-Sensitive Chondroitin Sulfate/Sodium Polystyrene Sulfonate Hydrogels for Controlled Drug Delivery

Ibuprofen is an antipyretic and analgesic drug used for the management of different inflammatory diseases, such as rheumatoid arthritis and osteoarthritis. Due to a short half-life and rapid elimination, multiple doses of ibuprofen are required in a day to maintain pharmacological action for a long duration of time. Due to multiple intakes of ibuprofen, certain severe adverse effects, such as gastric irritation, bleeding, ulcers, and abdominal pain are produced. Therefore, a system is needed which not only prolongs the release of ibuprofen but also overcomes the drug’s adverse effects. Hence, the authors have synthesized chondroitin sulfate/sodium polystyrene sulfonate–co-poly(acrylic acid) hydrogels by the free radical polymerization technique for the controlled release of ibuprofen. Sol-gel, porosity, swelling, and drug release studies were performed on the fabricated hydrogel. The pH-responsive behavior of the fabricated hydrogel was determined by both swelling and drug release studies in three different pH values, i.e., pH 1.2, 4.6, and 7.4. Maximum swelling and drug release were observed at pH 7.4, as compared to pH 4.6 and 1.2. Similarly, the structural arrangement and crosslinking of the hydrogel contents were confirmed by Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) evaluated the hard and irregular surface with a few macrospores of the developed hydrogel, which may be correlated with the strong crosslinking of polymers with monomer content. Similarly, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) demonstrated the high thermal stability of the formulated hydrogel, as compared to pure polymers. A decrease in the crystallinity of chondroitin sulfate and sodium polystyrene sulfonate after crosslinking was revealed by powder X-ray diffraction (PXRD). Thus, considering the results, we can demonstrate that a developed polymeric network of hydrogel could be used as a safe, stable, and efficient carrier for the controlled release of ibuprofen.

Poly(Lactic Acid)-Based Microparticles for Drug Delivery Applications: An Overview of Recent Advances

The sustained release of pharmaceutical substances remains the most convenient way of drug delivery. Hence, a great variety of reports can be traced in the open literature associated with drug delivery systems (DDS). Specifically, the use of microparticle systems has received special attention during the past two decades. Polymeric microparticles (MPs) are acknowledged as very prevalent carriers toward an enhanced bio-distribution and bioavailability of both hydrophilic and lipophilic drug substances. Poly(lactic acid) (PLA), poly(lactic-co-glycolic acid) (PLGA), and their copolymers are among the most frequently used biodegradable polymers for encapsulated drugs. This review describes the current state-of-the-art research in the study of poly(lactic acid)/poly(lactic-co-glycolic acid) microparticles and PLA-copolymers with other aliphatic acids as drug delivery devices for increasing the efficiency of drug delivery, enhancing the release profile, and drug targeting of active pharmaceutical ingredients (API). Potential advances in generics and the constant discovery of therapeutic peptides will hopefully promote the success of microsphere technology.

Star-shaped poly(ε-caprolactones) with well-defined architecture as potential drug carriers

The present study reported on the potential application of star-shaped poly(?-caprolactones) with different number of arms as new drug delivery matrix. Linear and star-shaped PCL ibuprofen loaded microspheres were prepared using oil-in-water (o/w) solvent evaporation technique and characterized with FTIR, DSC, XRD and SEM analysis. High yield, encapsulation efficiency and drug loadings were obtained for all microspheres. FTIR analysis revealed the existence of interactions between polymer matrix and drug, while the DSC analysis suggested that drug was encapsulated in an amorphous form. SEM analysis confirmed that regular, spherical in shape star-shaped microspheres, with diameter between 80 to 90 ?m, were obtained, while quite larger microspheres, 110 ?m, were prepared from linear PCL. The advantage of using star-shaped PCL microspheres instead of linear PCL was seen from drug release profiles which demonstrated higher amount of drug released from star-shaped polymer matrix as a consequence of their branched, flexible structure. Microspheres prepared from the polymers with the most branched structure showed the highest amount of released drug after 24 h. Finally, cytotoxicity tests, performed using normal human fibroblasts (MRC5), indicated absence of cytotoxicity at lower concentrations of microspheres proving the great potential of star-shaped PCL systems in comparison to linear ones.

Preparation and In Vitro Evaluation of Aspartic/Alginic Acid Based Semi-Interpenetrating Network Hydrogels for Controlled Release of Ibuprofen

Different combinations of polymers, aspartic acid (ASP), alginic acid (AL), and monomer acrylic acid (AA) were crosslinked in the presence of an initiator ammonium peroxodisulfate (APS) and cross-linker ethylene glycol dimethacrylate (EGDMA) to develop aspartic acid/alginic acid-co-poly(acrylic acid) (ASP/ALPAA) (semi-interpenetrating polymer network (SIPN)) hydrogels by the free radical polymerization technique for the controlled delivery of ibuprofen (IBP). Various studies such as dynamic swelling studies, drug loading, in vitro drug release and sol-gel analysis were carried out for the hydrogels. Higher swelling was observed at higher pH 7.4 as compared to lower pH 1.2, due to the presence of carboxylic groups of polymers and the monomer. Hence, pH-dependent swelling was exhibited by the developed hydrogels which led to a pH-dependent drug release and vice versa. The structural properties of the hydrogels were assessed by FTIR, PXRD, TGA, DSC, and SEM which confirmed the fabrication and stability of the developed structure. FTIR analysis revealed the reaction of both polymers with the monomer during the polymerization process and confirmed the overlapping of the monomer on the backbone of the both polymers. The disappearance of high intense crystalline peaks and the encapsulation of the drug by the hydrogel network was confirmed by PXRD. TGA and DSC showed that the developed hydrogels were thermally more stable than their basic ingredients. Similarly, the surface morphology of the hydrogels was analyzed by SEM and showed a smooth surface with few pores. Conclusively, ASP/ALPAA hydrogels have the potential to deliver IBP for a long period of time in a controlled way.

Optimization of ultraviolet/ozone (UVO3) process conditions for the preparation of gelatin coated polystyrene (PS) microcarriers

The aim of this study was to develop gelatin coated polystyrene (PS) microcarriers with good cell adhesion and proliferation properties. PS microspheres, prepared using oil-in water (o/w) solvent evaporation method, were loaded with oxygen containing functional groups using an ultraviolet/ozone (UVO₃) system. Using water-soluble carbodiimide chemistry, gelatin was subsequently immobilized on UVO₃ treated PS microspheres. The amount of immobilized gelatin was found to be directly proportional to the surface carboxyl (COOH) concentration on PS microspheres. Face Centered Central Composite Design (FCCD) was employed to optimize the process conditions of UVO₃ treatment to maximize the surface COOH concentration on PS microspheres for allowing higher gelatin immobilization. Statistical results revealed that, the optimized process conditions were ozone flow rate of ∼64,603 ppm, exposure time of ∼60 minutes and sample amount of 5.05 g. Under these conditions, the surface COOH concentration on PS microspheres was ∼1,505 nmol/g with the corresponding amount of immobilized gelatin was ∼2,725 µg/g. Characterization analyses strongly suggest that the optimized UVO₃ treatment and successive gelatin immobilization have successfully improved surface wettability and dispersion stability of PS microspheres. Moreover, gelatin coated PS microcarriers were also proven as able to support the growth of CHO-K1 cells in high cell density culture.

Systemic delivery of CRISPR/Cas9 with PEG-PLGA nanoparticles for chronic myeloid leukemia targeted therapy

Chronic myeloid leukemia (CML), which is characterized by the Philadelphia translocation, which fuses breakpoint cluster region (BCR) sequences from chromosome 22 upstream of the Abelson murine leukemia viral oncogene homolog (ABL) on chromosome 9, requires specific and efficient treatment. The CRISPR/Cas9 system, with its mechanism of specific DNA complementary recognition by engineered guide RNA (gRNA), allows the development of novel therapeutics for CML. To achieve targeted therapy of CML with the CRISPR/Cas9 system, we encapsulated a CRISPR/Cas9 plasmid (pCas9) expressing gRNA targeting the overhanging fusion region of the BCR-ABL gene (pCas9/gBCR-ABL) with poly(ethylene glycol)-b-poly(lactic acid-co-glycolic acid) (PEG-PLGA)-based cationic lipid-assisted polymeric nanoparticles (CLANs), which specifically disrupted the CML-related BCR-ABL gene while sparing the BCR and ABL genes in normal cells. After intravenous injection, CLANs carrying pCas9/gBCR-ABL (CLANpCas9/gBCR-ABL) efficiently knocked out the BCR-ABL fusion gene of CML cells and improved the survival of a CML mouse model, indicating that the combination of the CRISPR/Cas9 system with nanocarriers is a promising strategy for targeted treatment of CML.

SPHRINT - Printing Drug Delivery Microspheres from Polymeric Melts

This paper describes a simple, straightforward, and rapid method for producing microspheres from molten polymers by merely printing them in an inkjet-like manner onto a superoleophobic surface (microsphere printing, hence SPHRINT). Similar to 3D printing, a polymer melt is deposited onto a surface; however, in contrast to 2D or 3D printing, the surface is not wetted (i.e. exhibiting high contact angles with liquids, above 150°, due to its low surface energy), resulting in the formation of discrete spherical microspheres. In this study, microspheres were printed using polycaprolactone and poly(lactic-co-glycolic acid) loaded with a model active pharmaceutical ingredient-ibuprofen (IBU). The formation of microspheres was captured by high-speed imaging and was found to involve several physical phenomena characterized by non-dimensional numbers, including the thinning and breakup of highly viscous, weakly elastic filaments, which are first to be described in pure polymer melts. The resulting IBU-loaded microspheres had higher sphericity, reproducible sizes and shapes, and superior drug encapsulation efficiencies with a distinctly high process yield (>95%) as compared to the conservative solvent-based methods used presently. Furthermore, the microspheres showed sustained release profiles.

Electrospun API-loaded mixed matrix membranes for controlled release

The development of biocompatible membrane materials capable of delivering active pharmaceutical ingredients (APIs) over a fixed time period offers significant advantages to the pharmaceutical and biomedical industries alike.

One-pot preparation of polylactic acid-ibuprofen conjugates and their performance characterization

Merging esterification modification, carrier preparation, and chemical conjugation into a one-pot reaction as a new strategy for developing the polylactic acid-ibuprofen conjugates is described.

Enzymatic Polymerization of an Ibuprofen-Containing Monomer and Subsequent Drug Release

Novel ibuprofen-containing monomers comprising naturally occurring and biocompatible compounds were synthesized and subsequently polymerized via enzymatic methods. Through the use of a malic acid sugar backbone, ibuprofen was attached as a pendant group, and then subsequently polymerized with a linear aliphatic diol (1,3-propanediol, 1,5-pentanediol, or 1,8-octanediol) as comonomer using lipase B from Candida antarctica, a greener alternative to traditional metal catalysts. Polymer structures were elucidated by nuclear magnetic resonance and infrared spectroscopies, and thermal properties and molecular weights were determined. All polymers exhibited sustained ibuprofen release, with the longer chain, more hydrophobic diols exhibiting the slowest release over the 30 d study. Polymers were deemed cytocompatible using mouse fibroblasts, when evaluated at relevant therapeutic concentrations. Additionally, ibuprofen retained its chemical integrity throughout the polymerization and in vitro hydrolytic degradation processes. This methodology of enzymatic polymerization of a drug presents a more environmentally friendly synthesis and a novel approach to bioactive polymer conjugates.

Preparation and evaluation of microspheres prepared from novel polyester-ibuprofen conjugates blended with non-conjugated ibuprofen

A novel polyester, poly(glycerol-adipate-co-omega-pentadecalactone) (PGA-co-PL), was conjugated with a model drug, ibuprofen, through the free hydroxyl groups of the former and the free carboxyl group of the latter at various levels of substitution. The conjugated material was processed into microspheres by both emulsion solvent evaporation and spray-drying methods. Samples of conjugated material were also blended with non-conjugated drug and the microspheres produced were evaluated by various methods. Morphologically, the microspheres produced were satisfactory. However, there was some initial burst drug release from all samples, probably due to the presence of non-conjugated drug. Subsequent drug release was very slow due to the relative stability of the covalent bonding of the drug-polyester conjugate. Stability tests showed that storage at high relative humidity resulted in increased burst release.

Sustained antibacterial activity of doxycycline-loaded poly(D,L-lactide-co-glycolide) and poly(epsilon-caprolactone) nanoparticles

AIM

To increase the entrapment efficiency of doxycycline (DXY)-loaded poly(D,L-lactide-co-glycolide) (PLGA):poly(epsilon-caprolactone) (PCL) nanoparticles by up to 70% by varying the different formulation parameters such as polymer ratio, amount of drug loading (w/w), solvent selection, electrolyte addition and pH in the formulation.

METHOD

Biodegradable polymers PLGA and PCL are used in various ratios for nanoparticle preparation using the water-in-oil-in-water double emulsion technique for water-soluble DXY. The physicochemical characterization of nanoparticles included size and surface charge measurement, study of surface morphology using scanning-electron microscopy, Fourier transform infrared spectroscopy study, differential scanning calorimetry analysis and in vitro release kinetics study.

RESULTS

The mean particle size ranged from 230 to 360 nm, as measured by dynamic laser light scattering, and scanning-electron microscopy confirmed the spherical nature and smooth surface of the nanoparticles. Fourier transform infrared spectroscopy analysis of void nanoparticles, drug-loaded nanoparticles and native DXY indicated no interaction between the drug and polymer in the nanoparticle. Differential scanning calorimetry analysis of drug-loaded nanoparticles indicated a molecular level dispersion of DXY in the formulation. The antibacterial activity of native DXY and DXY-loaded nanoparticles were tested using a strain of Escherichia coli (DH5alpha) through growth inhibition and colony-counting method. The results indicated that DXY-loaded nanoparticles are more effective than native DXY due to the sustained release of DXY from nanoparticles in the E. coli strain.

Synthesis and evaluation of novel polyester-ibuprofen conjugates for modified drug release

Ibuprofen was conjugated at different levels to a novel polyester, poly(glycerol-adipate-co-omega-pentadecalactone) (PGA-co-PL), via an ester linkage to form a prodrug. The conjugates were characterized by differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), infrared (IR), gel permeation chromatography (GPC), ultraviolet (UV), and high-performance liquid chromatography (HPLC). The conjugates had a molecular weight between 18 and 24 kDa, and there was a suppression of the free hydroxyl groups within the conjugated polymer. DSC scans showed a lowering of the melting point (T(m)) when compared with the polyester alone and a difference in the number and area of T(m) peaks. Drug release studies showed an initial burst release (13-18%) followed thereafter by very slow release (maximum 35% after 18 days). Continuous work may produce ester-linked conjugates that are sufficiently labile to allow for complete release of ibuprofen over the time period studied.