Drug self-delivery systems for cancer therapy.

Biomaterial-based drug delivery systems used to improve chemotherapeutic activity of pharmaceuticals and to target inhibitors of apoptosis proteins

The development of drug delivery systems (DDSs) using near infrared (NIR) light and upconversion nanoparticles (UCNPs) has generated intensive interest over the past five years. These NIR‐initiated DDSs not only offer a high degree of spatial and temporal determination of therapeutic release but also provide precise control over the released dosage. Furthermore, these nanoplatforms confer several advantages over conventional light‐based DDSs—NIR offers better tissue penetration depth and a reduced risk of cellular photo‐damage caused by exposure to light at high‐energy wavelengths (e.g., ultraviolet light, <400 nm). The development of DDSs that can be activated by low intensity NIR illumination is highly desirable to avoid exposing living tissues to excessive heat that can limit the in vivo application of these DDSs. This encompasses research in three directions: (i) enhancing the quantum yield of the UCNPs; (ii) incorporation of photo‐responsive materials with red‐shifted absorptions into the UCNPs; and (iii) tuning the UCNPs excitation wavelength. This review focuses on recent advances in the development of NIR‐initiated DDS, with emphasis on the use of photo‐responsive compounds and polymeric materials conjugated onto UCNPs. The challenges that limit UCNPs clinical applications, alongside with the aforementioned techniques that have emerged to overcome these limitations, are highlighted.

Complex diseases and diverse clinical needs necessitate drug delivery systems (DDSs), yet the current performance of DDSs is far from ideal. Supramolecular interactions play a pivotal role in various aspects of drug delivery, encompassing biocompatibility, drug loading, stability, crossing biological barriers, targeting, and controlled release. Nevertheless, despite having some understanding of the role of supramolecular interactions in drug delivery, their incorporation is frequently overlooked in the design and development of DDSs. This perspective provides a brief analysis of the involved supramolecular interactions in the action of drug delivery, with a primary emphasis on the DDSs employed in the clinic, mainly liposomes and polymers, and recognized phenomena in research, such as the protein corona. The supramolecular interactions implicated in various aspects of drug delivery systems, including biocompatibility, drug loading, stability, spatiotemporal distribution, and controlled release, were individually analyzed and discussed. This perspective aims to trigger a comprehensive and systematic consideration of supramolecular interactions in the further development of DDSs. Supramolecular interactions embody the true essence of the interplay between the majority of DDSs and biological systems.

In the development of colloidal lipid drug delivery systems (DDS), the localization of the drug within the DDS, the protective potential of the DDS as well as the compatibility of the drug with the excipients are of special interest. In this study, Coumarin 6 (C6), a fluorescent dye frequently used to facilitate the traceability of DDS in vitro, is demonstrated as a tool to gain insight into the aforementioned properties by fluorescence spectroscopy. Both ways of loading C6 to solid colloidal DDS (pre‐loading to the lipid matrix or post‐loading to the ready DDS after its processing) led to a localization of C6 in the interfacial layer between solid lipid nanoparticles (SLN) and aqueous medium. In the case of pre‐loading, C6 is homogenously distributed in emulsion droplets and expelled from the lipid matrix due to crystallization. Nanoemulsions distributed C6 in the liquid lipid matrix itself and cause a hypsochromic shift of fluorescence spectra. Larger surface areas of emulsion droplets due to smaller droplet sizes displayed more interaction of C6 with the aqueous phase as a bathochromic shoulder in fluorescence spectra. Measured fluorescence intensity was linearly dependent on light scattering of colloidal DDS of the same excipients. A simple method to evaluate the protective properties of DDS was presented and displayed that (i) nanoemulsions provide more protection compared with SLN and (ii) higher phospholipid concentration improve the protection within SLN.Practical applications: In the development of colloidal DDS, it is important to identify the localization and distribution of a (model) drug in compartments within the disperse system. The simple approach by fluorescence spectroscopy presented in this study supplies information about the localization of drug substances with properties comparable with the fluorescent probe used. The results assist formulation development as a quick screening tool to elucidate (i) the localization of the probe, (ii) the microenvironment of the probe (e.g., differentiation of the physical state of the disperse phase), and (iii) the protection of the probe against damaging agents from the aqueous phase.The fluorescent dye Coumarin 6 was applied as model drug in colloidal lipid drug delivery systems. Fluorescence spectroscopy proved able to identify the localization of the model compound, the physical state of the dispersed phase, and the protective potential of the DDS, especially dependent on phospholipid concentration.

Melanoma is a rare but highly aggressive form of skin cancer that can rapidly metastasize, leading to a significant mortality rate. A main challenge in chemotherapy is the lack of selectivity in drug delivery to tumor sites, which affects both tumor and healthy tissues. Developing drug delivery systems (DDS) capable of preferentially interacting with transporters expressed on cancer cells may help address this issue. Carbon dots (CDs) have emerged as promising tools for the advancement of DDS due to their distinctive fluorescent characteristics, good water solubility, biocompatibility, and straightforward fabrication. In this work, CDs were synthesized via a facile method and conjugated with tryptophan (Trp) to evaluate their potential application as a DDS in melanoma. The fabricated CDs were characterized for their size, surface charge, optical properties, functional groups, and elemental analysis. LAT1 expression was examined by immunofluorescence, confirming higher levels in SK-MEL-2 melanoma cells compared to HK-2 normal kidney cells. Biocompatibility was established before conjugating CDs with tryptophan (Trp), ditryptophan (di-Trp), and tritryptophan (tri-Trp) and assessing their size, functional groups, and optical characteristics. Cellular uptake studies showed preferential uptake of Trp-conjugated CDs in SK-MEL-2 cells over HK-2 cells, indicating that tri-Trp-CDs exhibited the highest uptake. Molecular dynamics simulations suggested potential CDs-LAT1 interactions via van der Waals and electrostatic interactions. Trp-conjugated CDs were biocompatible with both SK-MEL-2 and HK-2 cells and could be electrostatically loaded with doxorubicin (DOX), exhibiting enhanced cytotoxicity against SK-MEL-2 cells compared to DOX alone. A trend toward greater selectivity for SK-MEL-2 cells over normal cells was observed, with tri-Trp/DOX showing the most pronounced effect, possibly reflecting LAT1-1 mediated uptake. These findings suggest that Trp-modified CDs may serve as promising DDS candidates for melanoma treatment.

The technology of pharmaceutical drug delivery systems (DDS) as an individual and adjustable tool for drug administration has been intensively developed in the last years. Additive manufacturing (AM) techniques, such as stereolithography, are a promising approach towards DDS scaffold manufacturing. Stereolithography, by using layerby- photo-polymerisation, creates DDS scaffolds with highly controlled 3D geometry. Combined with inkjet printing it allows a very precise positioning of the drug depot in the basic scaffold and therefore also a better control of the drug release. Furthermore, this hybrid AM technique also allows for the creation of a multi-drug DDS with a several drug depots localized in desired positions within the scaffold. Determination of the scaffold and drug depot material properties is one of the initial steps for such novel DDS development. Basic characteristics, such as stiffness, elasticity or glass transition temperature (Tg), are important for designing and adapting the material for biomedical application. The photosensitive poly(ethylene glycol) diacrylate (PEGDA) can be easily formed into a desired biocompatible scaffold geometry via stereolithography. In this study we have focused on the evaluation of PEGDA (Mn=700 g/mol) as a pure and copolymer system in combination with other acrylates (butanediol diacrylate, pentaerythritol triacrylate) as possible materials for DDS using this novel hybrid AM technique. Irgacure 2959, a biocompatible photoinitiator (PI), was used as a radical starter for photopolymerisation. Samples varying in PI and coacrylate concentration were prepared by conventional photopolymerisation. Physico-chemical analyses of the samples were performed and several parameters, such as stiffness, elongation at break and glass transition temperatures, were determined.

Advanced drug delivery systems for therapeutic applications.

Exosomes are secretory membrane vesicles containing lipids, proteins, and nucleic acids. They act as intercellular transporters by delivering their components to exosome recipient cells. Based on their endogenous delivery system properties, exosomes are expected to become drug delivery systems (DDS) for various molecules such as nucleic acid-based drugs. Important factors such as drug loading to exosomes, production, and pharmacokinetics of exosomes need to be considered for the development of exosome-based DDS. Of these, the pharmacokinetics of exosomes have rarely been studied, probably because of the lack of quantitative evaluation methods of in vivo exosomal pharmacokinetics. We selected lactadherin as an exosome tropic protein and developed it as a fusion protein with Gaussia luciferase to label exosomes for in vivo imaging. In addition, a fusion protein of lactadherin and streptavidin was developed, and the tissue distribution of exosomes was quantitatively evaluated by radiolabeling the exosomes using (125)I-labeled biotin. Using labeled exosomes, we found that intravenously injected exosomes were rapidly cleared from the systemic circulation by macrophages. In addition, the exosomes were mainly distributed to the liver, lung, and spleen. We also examined the effect of exosome isolation methods on their physicochemical and pharmacokinetic properties. We found that exosomes collected by the ultracentrifugation-based density-gradient method were more dispersed than exosomes collected by other methods, including the ultracentrifugation-based pelleting method. The gradient method is more time-consuming than others; therefore the development of a more efficient method for exosome isolation will advance the development of exosome-based DDS.

Recent research on idealizing drug delivery system which is progressing at a prodigious rate and aims at development of drug delivery system (DDS), with maximum therapeutic advantages of drug delivery, thus resulting in safe and effective management of disease. More and more developments in delivery systems are being integrated to optimize the efficacy and cost effectiveness of the therapy. New classes of pharmaceuticals, biopharmaceuticals are fueling the rapid evolution of drug delivery technology. Microsponge technology has been introduced in topical drug products to facilitate the controlled release of active drug into the skin in order to reduce systemic exposure and minimize local cutaneous reactions to active drugs. Microsponge consists of microporous beads loaded with active agent. When applied to the skin, the microsponge releases its active ingredient on a time mode and also in response to other stimuli (rubbing, temperature, pH etc.) that are used mostly for topical and recently for oral administration Microsponges are porous, polymeric microspheres that are mostly used for prolonged topical administration. Microsponges are designed to deliver a pharmaceutically active ingredient efficiently at minimum dose and also to enhance stability, reduce side effects, and modify drug release profiles. Microsponges are prepared by several methods utilizing emulsion system or by suspension polymerization in a liquid–liquid system. The most common emulsion system used is oil-in-water (o/w), with the microsponges being produced by the emulsion solvent diffusion (ESD) method. Microsponge delivery system (MDS) can provide increased efficacy for topically active agents with enhanced safety, extended product stability, enhanced formulation flexibility, reduced side effects and improved aesthetic properties in an efficient and novel manner. In addition these are non-irritating, non-mutagenic, non-allergenic, and nontoxic. The present review introduces microsponge technology in great detail.

Over the past decade, new technologies have emerged to increase intrinsic potency, enhance bioavailability, and improve targeted delivery of drugs. Most pharmaceutical formulations require multiple dosing due to their fast release and short elimination kinetics, increasing the risk of adverse events and patient non-compliance. Due to these limitations, enormous efforts have focused on developing drug delivery systems (DDSs) for sustained release and targeted delivery. Sustained release strategies began with pioneering research using silicone rubber embedding for small molecules and non-inflammatory polymer encapsulation for proteins or DNA. Subsequently, numerous DDSs have been developed as controlled-release formulations to deliver systemic or local therapeutics, such as small molecules, biologics, or live cells. In this review, we discuss the latest developments of DDSs, specifically nanoparticles, hydrogels, and microgrippers for the delivery of systemic or localized drugs to the gastrointestinal (GI) tract. We examine innovative DDS design and delivery strategies tailored to the GI tract's unique characteristics, such as its extensive length and anatomical complexity, varying pH levels and enzymatic activity across different sections, and intrinsic peristalsis. We particularly emphasize those designed for the treatment of inflammatory bowel disease (IBD) with in vivo preclinical studies.

The recent advances in pharmaceutical technology have been promoted in a strong relation to taking the data to prove the efficacy and safety in drug development activities and also to designing new dosage forms with high stability and suitable bioavailability.The development of pharmaceutical technology may be divided historically as follows: a) pre-pharmaceutical (without consideration on bioequivalence); b) first generation (conventional or regular preparations); c) second generation (regular controlled release preparations); d) third generation (precisely controlled release preparations, i. e., drug delivery systems (DDS) and transdermal therapeutic systems (TTS)); e) fourth generation (drug targeting, missile). We can find materialized ones on d) the third generation, as it may be promising on e) the fourth generation in future. In a wide sense, the above-mentioned d) and e) are classified into drug delivery systems (wide-DDS), as the former may be the first generation of wide-DDS and the latter the second generation of wide-DDS.Noticeable ones in recent advances in pharmaceutical technology are concerned with developments of DDS and TTS. Generally these technologies are formed on the basis of utilization of interactions of drugs with surrounding components such as on a) inter-molecular level; b) particle coating; c) particle-particle interactions d) miscellaneous. The surrounding components thereby include body tissues and organs, and thus a triple interaction among drug, dosage form components and body components should be considered.We have investigated several topical membrane adhesive dosage forms containing hydroxypropyl cellulose and Carbopol to find such an advanced technology as mentioned above. Here will be described:(1) topical dosage form for carcinoma colli, (2) oral mucosal dosage form for the absorption of insulin, (3) adhesive tablet for aphthous stomatitis, and powder dosage form of nasal absorption of insulin.

Triblock copolymers have been widely used as a material for developing drug delivery systems (DDS). In terms of architecture, triblock copolymers could be classified into symmetric and asymmetric triblock copolymers. Different types of nano-sized structures such as star micelles, flower-like micelles, and polymer vesicles could be prepared from these block copolymers, which would be very potential in delivering various types of agents such as chemical drugs, genes, and contrast agents. Additionally, the nano-sized carriers have been fabricated for environmentally sensitive (pH-sensitive or temperature sensitive) DDS or for enhancing the gene delivery efficiency. Due to their versatility in structures and drug delivery capacity, the application of triblock copolymers would definitely be expanded in near future.

Programmed near-infrared light-responsive drug delivery system for combined magnetic tumor-targeting magnetic resonance imaging and chemo-phototherapy.

The aim was to assess the suitability of three nano-based transdermal drug delivery systems containing ibuprofen: a nano-emulsion, a nano-emulgel, and a colloidal suspension with ibuprofen-loaded nanoparticles. Understanding the transdermal delivery of ibuprofen using nano-based drug delivery systems can lead to more effective pain relief and improved patient compliance. Characterization tests assessed the suitability of the developed drug delivery systems. Membrane release and skin diffusion studies, along with tape stripping, were performed to determine drug release and skin permeation of ibuprofen. In vitro cytotoxicity studies on HaCaT cells were conducted using MTT and neutral red assays to evaluate the safety of the developed drug delivery systems. Characterization studies confirmed stable drug delivery systems with ideal properties for transdermal delivery. Membrane release studies demonstrated the successful release of ibuprofen. In vitro skin diffusion experiments and tape stripping, detecting ibuprofen in the receptor phase, stratum corneum-epidermis, and epidermis-dermis, indicating successful transdermal and topical delivery. The in vitro cytotoxicity studies observed only minor cytotoxic effects on HaCaT cells, indicating the safety of the developed drug delivery systems. The investigation demonstrated promising results for the transdermal delivery of ibuprofen using the developed drug delivery systems, which contributes to valuable insights that may lead to improved pain management strategies.

It is well known that metal–organic framework (MOF) nanostructures have unique characteristics such as high porosity, large surface areas and adjustable functionalities, so they are ideal candidates for developing drug delivery systems (DDSs) as well as theranostic platforms in cancer treatment. Despite the large number of MOF nanostructures that have been discovered, conventional MOF-derived nanosystems only have a single biofunctional MOF source with poor colloidal stability. Accordingly, developing core–shell MOF nanostructures with good colloidal stability is a useful method for generating efficient drug delivery, multimodal imaging and synergistic therapeutic systems. The preparation of core–shell MOF nanostructures has been done with a variety of materials, but inorganic nanoparticles (NPs) are highly effective for drug delivery and imaging-guided tumor treatment. Herein, we aimed to overview the synthesis of core–shell inorganic NP@MOF nanostructures followed by the application of core–shell MOFs derived from magnetic, quantum dots (QDs), gold (Au), and gadolinium (Gd) NPs in drug delivery and imaging-guided tumor treatment. Afterward, we surveyed different factors affecting prolonged drug delivery and cancer therapy, cellular uptake, biocompatibility, biodegradability, and enhanced permeation and retention (EPR) effect of core–shell MOFs. Last but not least, we discussed the challenges and the prospects of the field. We envision this article may hold great promise in providing valuable insights regarding the application of hybrid nanostructures as promising and potential candidates for multimodal imaging-guided combination cancer therapy.