The purpose of this study was to fabricate insulin-loaded double-walled and single-polymer poly(lactide-co-glycolide) (PLGA) microspheres using a fast degrading glucose core, hydroxyl-terminated poly(lactide-co-glycolide) (Glu-PLGA), and a moderate degrading carboxyl-terminated PLGA polymers. A modified water-in-oil-in-oil-in-water (w/o/o/w) emulsion solvent evaporation technique was employed to prepare double-walled microspheres, whereas single-polymer microspheres were fabricated by a conventional water-in-oil-in-water (w/o/w) emulsion solvent evaporation method. The effect of fabrication techniques and polymer characteristics on microspheres size, morphology, encapsulation efficiency, in vitro release, and insulin stability was evaluated. The prepared double-walled microspheres were essentially non-porous, smooth surfaced, and spherical in shape, whereas single-polymer microspheres were highly porous. Double-walled microspheres exhibited a significantly reduced initial burst followed by sustained and almost complete release of insulin compared to single-polymer microspheres. Initial burst release was further suppressed from double-walled microspheres when the mass ratio of the component polymers was increased. In conclusion, double-walled microspheres made of Glu-PLGA and PLGA can be a potential delivery system of therapeutic insulin.
The aim of this study was to employ experimental and molecular modelling approaches to use molecular level interactions to rationalise the selection of suitable polymers for use in the production of stable domperidone (DOMP) nanocrystals with enhanced bioavailability. A low-energy antisolvent precipitation method was used for the preparation and screening of polymers for stable nanocrystals of DOMP. Ethyl cellulose was found to be very efficient in producing stable DOMP nanocrystals with particle size of 130 ± 3 nm. Moreover, the combination of hydroxypropyl methylcellulose and polyvinyl alcohol was also shown to be better in producing DOMP nanocrystals with smaller particle size (200 ± 3.5 nm). DOMP nanosuspension stored at 2-8 °C and at room temperature (25 °C) exhibited better stability compared to the samples stored at 40 °C. Crystallinity of the unprocessed and processed DOMP was monitored by differential scanning calorimetry and powder X-ray diffraction. DOMP nanocrystals gave enhanced dissolution rate compared to the unprocessed drug substance. DOMP nanocrystals at a dose of 10 mg/kg in rats showed enhanced bioavailability compared to the raw drug substance and marketed formulation. A significant increase in plasma concentration of 2.6 μg/mL with a significant decrease in time (1 h) to reach maximum plasma concentration was observed for DOMP nanocrystals compared to the raw DOMP. Molecular modelling studies provided underpinning knowledge at the molecular level of the DOMP-polymer nanocrystal interactions and substantiated the experimental studies. This included an understanding of the impact of polymers on the size of nanocrystals and their associated stability characteristics.
Skin substitutes are one of the main treatments for skin loss, and a skin substitute that is readily available would be the best treatment option. However, most cell-based skin substitutes require long production times, and therefore, patients endure long waiting times. The proteins secreted from the cells and tissues play vital roles in promoting wound healing. Thus, we aimed to develop an acellular three-dimensional (3D) skin patch with dermal fibroblast conditioned medium (DFCM) and collagen hydrogel for immediate treatment of skin loss. Fibroblasts from human skin samples were cultured using serum-free keratinocyte-specific media (KM1 or KM2) and serum-free fibroblast-specific medium (FM) to obtain DFCM-KM1, DFCM-KM2, and DFCM-FM, respectively. The acellular 3D skin patch was soft, semi-solid, and translucent. Collagen mixed with DFCM-KM1 and DFCM-KM2 showed higher protein release compared to collagen plus DFCM-FM. In vitro and in vivo testing revealed that DFCM and collagen hydrogel did not induce an immune response. The implantation of the 3D skin patch with or without DFCM on the dorsum of BALB/c mice demonstrated a significantly faster healing rate compared to the no-treatment group 7 days after implantation, and all groups had complete re-epithelialization at day 17. Histological analysis confirmed the structure and integrity of the regenerated skin, with positive expression of cytokeratin 14 and type I collagen in the epidermal and dermal layer, respectively. These findings highlight the possibility of using fibroblast secretory factors together with collagen hydrogel in an acellular 3D skin patch that can be used allogeneically for immediate treatment of full-thickness skin loss.
Salicylates have a long history of use for pain relief. Salicylic acid and methyl salicylate are among the widely used topical salicylates namely for keratolytic and anti-inflammatory actions, respectively. The current review summarises both passive and active strategies, including emerging technologies employed to enhance skin permeation of these two salicylate compounds. The formulation design of topical salicylic acid targets the drug retention in and on the skin based on the different indications including keratolytic, antibacterial and photoprotective actions, while the investigations of topical delivery strategies for methyl salicylate are limited. The pharmacokinetics and metabolisms of both salicylate compounds are discussed. The current overview and future perspectives of the topical delivery strategies are also highlighted for translational considerations of formulation designs.
The biocompatible nature of mesoporous silica nanoparticles (MSN) attracted researchers' attention to deliver therapeutic agents in the treatment of various diseases, where their porous nature, high drug loading efficiency, and suitability to functionalize with a specific ligand of MSN helped to obtain the desired outcome. The application of MSN has been extended to deliver small chemicals to large-sized peptides or proteins to fight against complex diseases. Recently, formulation researches with MSN have been progressed for various non-conventional drug delivery systems, including liposome, microsphere, oro-dispersible film, 3D-printed formulation, and microneedle. Low bulk density, retaining mesoporous structure during downstream processing, and lack of sufficient in vivo studies are some of the important issues towards the success of mesoporous silica-based advanced drug delivery systems. The present review has aimed to evaluate the application of MSN in advanced drug delivery systems to critically analyze the role of MSN in the respective formulation over other functionalized polymers. Finally, an outlook on the future direction of MSN-based advanced drug delivery systems has been drawn against the existing challenges with this platform.
The delivery of drugs to the posterior segment of the eye remains a tremendously difficult task. Prolonged treatment in conventional intravitreal therapy requires injections that are administered frequently due to the rapid clearance of the drug molecules. As an alternative, intraocular implants can offer drug release for long-term therapy. However, one of the several challenges in developing intraocular implants is selecting an appropriate in vitro dissolution testing model. In order to determine the efficacy of ocular implants in drug release, multiple in vitro test models were emerging. While these in vitro models may be used to analyse drug release profiles, the findings may not predict in vivo retinal drug exposure as this is influenced by metabolic and physiological factors. This review considers various types of in vitro test methods used to test drug release of ocular implants. Importantly, it discusses the challenges and factors that must be considered in the development and testing of the implants in an in vitro setup.
Glioblastoma multiforme (GBM) is the most prevalent form of brain tumor, which generally has a poor prognosis. According to consensus, recurrence of the tumor and chemotherapy resistance acquisition are the two distinguishing features of GBM originated from glioblastoma stem cells (GSCs). To eliminate these obstacles inherent in GBM chemotherapy, targeting GSCs through a smart drug delivery system has come to the front position of GBM therapeutics. In this study, B19 aptamer (Apt)-conjugated polyamidoamine (PAMAM) G4C12 dendrimer nanoparticles (NPs), called Apt-NPs, were formulated for the co-delivery of paclitaxel (PTX) and temozolomide (TMZ) to U-87 stem cells. These drugs were loaded using a double emulsification solvent evaporation method. As a result, drug-loaded Apt-NPs significantly inhibited the tumor growth of U-87 stem cells, by the initiation of apoptosis via the downregulation of autophagic and multidrug resistance (MDR) genes. Additionally, by their downregulation by qPCR of CD133, CD44, SOX2, and the canonical Wnt/β-catenin pathway, cell proliferation has substantially decreased. Altogether, the results demonstrate that this intelligent drug co-delivery system is capable of effectively transferring PTX and TMZ to U-87 stem cells and without any toxic effect on Apt-NPs alone to U-87 stem cells. Furthermore, the designed dendrimer-based pharmaceutical system along with single-stranded B19 aptamer might be utilized as a new therapeutic strategy for the treatment of U-87 stem cells drug resistance in the GBM.
The involvement of recent technologies, such as nanotechnology and three-dimensional printing (3DP), in drug delivery has become the utmost importance for effective and safe delivery of potent therapeutics, and thus, recent advancement for oral drug delivery through 3DP technology has been expanded. The use of computer-aided design (CAD) in 3DP technology allows the manufacturing of drug formulation with the desired release rate and pattern. Currently, the most applicable 3DP technologies in the oral drug delivery system are inkjet printing method, fused deposition method, nozzle-based extrusion system, and stereolithographic 3DP. In 2015, the first 3D-printed tablet was approved by the US Food and Drug Administration (FDA), and since then, it has opened up more opportunities in the discovery of formulation for the development of an oral drug delivery system. 3DP allows the production of an oral drug delivery device that enables tailor-made formulation with customizable size, shape, and release rate. Despite the advantages offered by 3DP technology in the drug delivery system, there are challenges in terms of drug stability, safety as well as applicability in the clinical sector. Nonetheless, 3DP has immense potential in the development of drug delivery devices for future personalized medicine. This article will give the recent advancement along with the challenges of 3DP techniques for the development of oral drug delivery. Graphical abstract.
Wound healing is a physiological event that generates reconstitution and restoration of granulation tissue that ends with scar formation. As omega fatty acids are part of membrane phospholipids and participate in the inflammatory response, we investigated the effects of omega-3, omega-6, and omega-9 fatty acids in the form of oils on wound healing. Linseed (LO), evening primrose (EPO), and olive oils (OO) rich in omega-3, omega-6, and omega-9 fatty acids were formulated into emulsions and were topically applied on rats with excision wounds. All omega-3-, omega-6-, and omega-9-rich oil formulations were found to accelerate wound closure compared to untreated, with significant improvement (p
Docetaxel has demonstrated extraordinary anticancer effects on lung cancer. However, lack of optimal bioavailability due to poor solubility and high toxicity at its therapeutic dose has hampered the clinical use of this anticancer drug. Development of nanoemulsion formulation along with biocompatible excipients aimed for pulmonary delivery is a potential strategy to deliver this poorly aqueous soluble drug with improved bioavailability and biocompatibility. In this work, screening and selection of pharmaceutically acceptable excipients at their minimal optimal concentration have been conducted. The selected nanoemulsion formulations were prepared using high-energy emulsification technique and subjected to physicochemical and aerodynamic characterizations. The formulated nanoemulsion had mean particle size and ζ-potential in the range of 90 to 110 nm and - 30 to - 40 mV respectively, indicating high colloidal stability. The pH, osmolality, and viscosity of the systems met the ideal requirement for pulmonary application. The DNE4 formulation exhibited slow drug release and excellent stability even under the influence of extreme environmental conditions. This was further confirmed by transmission electron microscopy as uniform spherical droplets in nanometer range were observed after storage at 45 ± 1 °C for 3 months indicating high thermal stability. The nebulized DNE4 exhibited desirable aerosolization properties for pulmonary delivery application and found to be more selective on human lung carcinoma cell (A549) than normal cell (MRC-5). Hence, these characteristics make the formulation a great candidate for the potential use as a carrier system for docetaxel in targeting lung cancer via pulmonary delivery.
Inhalation therapy of lipid-based carriers has great potential in direct target towards the root of respiratory diseases, which make them superior over other drug deliveries. With the successful entry of lipid carriers into the target cells, drugs can be absorbed in a sustained release manner and yield extended medicinal effects. Nevertheless, translation of inhalation therapy from laboratory to clinic especially in drug delivery remains a key challenge to the formulators. An ideal drug vehicle should safeguard the drugs from any premature elimination, facilitate cellular uptake, and promote maximum drug absorption with negligible toxicity. Despite knowing that lung treatment can be done via systemic delivery, pulmonary administration is capable of enhancing drug retention within the lungs, while minimizing systemic toxicity with local targeting. Current inhalation therapy of lipid-based carriers can be administered either intratracheally or intranasally to reach deep lung. However, the complex dimensions of lung architectural and natural defense mechanism poise major barriers towards targeted pulmonary delivery. Delivery systems have to be engineered in a way to tackle various diseases according to their biological conditions. This review highlights on the developmental considerations of lipid-based delivery systems cater for the pulmonary intervention of different lung illnesses.
Ulcerative colitis (UC) is an inflammatory disease of the colon that severely affects the quality of life of patients and usually responds well to anti-inflammatory agents for symptomatic relief; however, many patients need colectomy, a surgical procedure to remove whole or part of the colon. Though various types of pharmacological agents have been employed for the management of UC, the lack of effectiveness is usually predisposed to various reasons including lack of target-specific delivery of drugs and insufficient drug accumulation at the target site. To overcome these glitches, many researchers have designed and characterized various types of versatile polymeric biomaterials to achieve target-specific delivery of drugs via oral route to optimize their targeting efficiency to the colon, to improve drug accumulation at the target site, as well as to ameliorate off-target effects of chemotherapy. Therefore, the aim of this review was to summarize and critically discuss the pharmaceutical significance and therapeutic feasibility of a wide range of natural and synthetic biomaterials for efficient drug targeting to colon and rationalized treatment of UC. Among various types of biomaterials, natural and synthetic polymer-based hydrogels have shown promising targeting potential due to their innate pH responsiveness, sustained and controlled release characteristics, and microbial degradation in the colon to release the encapsulated drug moieties. These characteristic features make natural and synthetic polymer-based hydrogels superior to conventional pharmacological strategies for the management of UC.
To investigate the use of chitosan nanoparticles (CS-TPP-NPs) as carriers for α- and β-arbutin. In this study, CS-TPP-NPs containing α- and β-arbutin were prepared via the ionic cross-linking of CS and TPP and characterized for particle size, zeta potential, and dispersity index. The entrapment efficiency and loading capacity of various β-arbutin concentrations (0.1, 0.2, 0.4, 0.5, and 0.6%) were also investigated. SEM, TEM FTIR, DSC and TGA analyses of the nanoparticles were performed to further characterize the nanoparticles. Finally, stability and release studies were undertaken to ascertain further the suitability of the nanoparticles as a carrier system for α- and β-arbutin. Data obtained clearly indicates the potential for use of CS-TPP-NPs as a carrier for the delivery of α- and β-arbutin. The size obtained for the alpha nanoparticles (α-arbutin CSNPs) ranges from 147 to 274 d.nm, with an increase in size with increasing alpha arbutin concentration. β-arbutin nanoparticles (β-arbutin CSNPs) size range was from 211.1 to 284 dn.m. PdI for all nanoparticles remained between 0.2-0.3 while the zeta potential was between 41.6-52.1 mV. The optimum encapsulation efficiency and loading capacity for 0.4% α-arbutin CSNPs were 71 and 77%, respectively. As for β-arbutin, CSNP optimum encapsulation efficiency and loading capacity for 0.4% concentration were 68 and 74%, respectively. Scanning electron microscopy for α-arbutin CSNPs showed a more spherical shape compared to β-arbutin CSNPs where rod-shaped particles were observed. However, under transmission electron microscopy, the shapes of both α- and β-arbutin CSNP nanoparticles were spherical. The crystal phase identification of the studied samples was carried out using X-ray diffraction (XRD), and the XRD of both α and β-arbutin CSNPs showed to be more crystalline in comparison to their free form. FTIR spectra showed intense characteristic peaks of chitosan appearing at 3438.3 cm-1 (-OH stretching), 2912 cm-1 (-CH stretching), represented 1598.01 cm-1 (-NH2) for both nanoparticles. Stability studies conducted for 90 days revealed that both α- and β-arbutin CSNPs were stable in solution. Finally, release studies of both α- and β-arbutin CSNPs showed a significantly higher percentage release in comparison to α- and β-arbutin in their free form. Chitosan nanoparticles demonstrate considerable promise as a carrier system for α- and β-arbutin, the use of which is anticipated to improve delivery of arbutin through the skin, in order to improve its efficacy as a whitening agent.
Carbon nanotubes (CNTs) possess outstanding properties that could be useful in several technological, drug delivery, and diagnostic applications. However, their unique physical and chemical properties are hindered due to their poor solubility. This article review's the different ways and means of solubility enhancement of single-wall carbon nanotubes (SWNTs). The advantages of SWNTs over the multi-walled carbon nanotubes (MWNTs) and the method of non-covalent modification for solubility enhancement has been the key interest in this review. The review also highlights a few examples of dispersant design. The review includes some interesting utility of SWNTs being wrapped with polymer especially in biological media that could mediate proper drug delivery to target cells. Further, the use of wrapped SWNTs with phospholipids, nucleic acid, and amphiphillic polymers as biosensors is of research interest. The review aims at summarizing the developments relating to wrapped SWNTs to generate further research prospects in healthcare.
Treatment of glioblastoma multiforme (GBM) is a predominant challenge in chemotherapy due to the existence of blood-brain barrier (BBB) which restricts delivery of chemotherapeutic agents to the brain together with the problem of drug penetration through hard parenchyma of the GBM. With the structural and mechanistic elucidation of the BBB under both physiological and pathological conditions, it is now viable to target central nervous system (CNS) disorders utilizing the presence of transferrin (Tf) receptors (TfRs). However, overexpression of these TfRs on the GBM cell surface can also help to avoid restrictions of GBM cells to deliver chemotherapeutic agents within the tumor. Therefore, targeting of TfR-mediated delivery could counteract drug delivery issues in GBM and create a delivery system that could cross the BBB effectively to utilize ligand-conjugated drug complexes through receptor-mediated transcytosis. Hence, approach towards successful delivery of antitumor agents to the gliomas has been making possible through targeting these overexpressed TfRs within the CNS and glioma cells. This review article presents a thorough analysis of current understanding on Tf-conjugated nanocarriers as efficient drug delivery system.
On account of heterogeneity, intrinsic ability of drug resistance, and the potential to invade to other parts of the body (malignancy), the development of a rational anticancer regimen is dynamically challenging. Chemotherapy is considered the gold standard for eradication of malignancy and mitigation of its reoccurrence; nevertheless, it has also been associated with detrimental effects to normal tissues owing to its nonselectivity and nominal penetration into the tumor tissues. In recent decades, nanotechnology-guided interventions have been well-acclaimed due to their ability to facilitate target-specific delivery of drugs, avoidance of nontarget distribution, alleviated systemic toxicity, and maximized drug internalization into cancer cells. Despite their numerous biomedical advantages, clinical translation of nanotechnology-mediated regimens is challenging due to their short plasma half-life and early clearance. PEGylation of nanomedicines has been adapted as an efficient strategy to extend plasma half-life and diminished early plasma clearance via alleviating the opsonization (uptake by monocytes and macrophages) of drug nanocarriers. PEGylation provides "stealth" properties to nanocarrier's surfaces which diminished their recognition or uptake by cellular immune system, leading to longer circulation time, reduced dosage and frequency, and superior site-selective delivery of drugs. Therefore, this review aims to present a comprehensive overview of the pharmaceutical advantages and therapeutic feasibility of PEGylation of nanocarriers in improving tumor-specific targetability, reversing drug resistance, and improving pharmacokinetic profile of drugs and anticancer efficacy. Challenges to PEGylated cancer nanomedicines, possible adaptations to resolve those challenges, and pivotal requirement for interdisciplinary research for development of rational anticancer regimen have also been pondered.
Azelaic acid (AzA) is a USFDA bioactive prescribed against acne vulgaris. It possesses delivery challenges like poor aqueous solubility, low skin-penetrability, and dose-dependent side effects, which could be overcome by its synergistic combination with tea tree oil (TTO) as a microemulsion (ME)-based hydrogel composite. AzA-TTO ME was prepared to employ pseudo-ternary phase diagram construction. The best AzA-TTO ME was of uniform size (polydispersity index 90%), and negative zeta potential (-1.42 ± 0.25% mV) values. ME hydrogel composite with optimum rheological and textural attributes showed better permeation, retention, and skin-compliant characteristics, vis-a-vis marketed formulation (Aziderm™) when evaluated in Wistar rat skin. In vitro antibacterial efficacy in bacterial strains, i.e., Staphylococcus aureus, Propionibacterium acne, and Staphylococcus epidermidis, was evaluated employing agar well plate diffusion and broth dilution assay. ME hydrogel has shown an increase in zone of inhibition by two folds and a decrease in minimum inhibitory concentration (MIC) by eightfold against P. acnes vis-a-vis AzA. Finally, ME hydrogel composite exhibited a better reduction in the papule density (93.75 ± 1.64%) in comparison to Aziderm™ 72.69 ± 4.67%) on acne as developed in rats by inducing testosterone. Thus, the developed AzA-TTO ME hydrogel composite promises an efficacious and comparatively safer drug delivery system for the topical therapy of acne vulgaris.
Hydrocortisone (HC), topical glucocorticoid along with hydroxytyrosol (HT), and anti-microbial- and anti-oxidant-loaded chitosan nanoparticles (CSNPs) were prepared in large scale and analyzed for their adverse effects on healthy human skin followed by repeated applications. Ten subjects were randomized to receive test (HC-HT CSNPs) and vehicle samples (aqueous (AQ) cream). They were applied on the arms for 28 days, and transepidermal water loss (TEWL), erythema intensity, and irritation score were measured. Blood samples were analyzed for blood hematology, blood biochemistry, and adrenal cortico-thyroid hormone (ACTH) levels. Skin biopsy was obtained to assess histopathological changes in the skin. HC-HT CSNP AQ cream was stored at 4, 25, and 45 °C for a period of 1 year, and its stability was assessed by monitoring their physical appearances, particle size, and pH. Spherical-shaped NPs were successfully upscaled using spinning-disc technology, with insignificant changes in particle size, zeta potential, and incorporation of drugs as compared to the well-established laboratory method. Particle size of HC-HT CSNPs was
Composite film dressings composed of pluronic F127 (PL)-pectin (PC) and pluronic (PL) F127-gelatin (GL) were investigated as potential drug delivery system for wound healing. Composite films were solvent cast by blending PL with PC or GL in different ratios using glycerol (2.5%) as plasticizer. Erythromycin (ER) (0.1%) was incorporated in films as model hydrophobic antibiotic. The optimized composite films were characterized for physical appearance, morphology, mechanical profile, and thermal behavior. In addition, drug release, antibacterial activity, and cytocompatibility of the films were investigated to assess their potential as drug delivery system. The composite films exhibited excellent wound dressing characters in terms of appearance, stability, and mechanical profile. Moreover, ER-loaded composite films released ER in controlled manner, exhibited antibacterial activity against Staphylococcus aureus, and were non-toxic to human skin fibroblast. These findings demonstrate that these composite films hold the potential to be formulated as antibacterial wound dressing.