Facile fabrication of microparticles with pH-responsive macropores for small intestine targeted drug formulation

Smart on-demand drug release strategies for cancer combination therapy

In cancer therapy, enhancing therapeutic indices and patient compliance has been a central focus in recent drug delivery technology development. However, achieving a delicate balance between improving anti-tumor efficacy and minimizing toxicity to normal tissues remains a significant challenge. With the advent of smart on-demand drug release strategies, new opportunities have emerged. These strategies represent a promising approach to drug delivery, enabling precise control over the release of therapeutic agents in a programmed and spatiotemporal manner. Recent studies have focused on designing delivery systems capable of releasing multiple therapeutic agents sequentially, while achieving spatial resolution in vivo. Smart on-demand drug release strategies have demonstrated considerable potential in tumor combination therapy for achieving precision drug delivery and controlled release by responding to specific physiological signals or external physical stimuli in the tumor microenvironment. These strategies not only improve tumor targeting and reduce toxicity to healthy tissues but also enable sequential release in combination therapy, allowing multiple drugs to be released in a specific spatiotemporal order to enhance synergistic treatment effects. In this paper, we systematically reviewed the current research progress of smart on-demand drug release drug delivery strategies in anti-tumor combination therapy. We highlighted representative integrated drug delivery systems and discussed the challenges associated with their clinical application. Additionally, potential future research directions are proposed to further advance this promising field.

Spray-Dried Powders of Casein-Encapsulated Rutin Stabilized With Sugars for the Enhancement of Intestinal Drug Solubility

Numerous therapeutic potentials of rutin (RUT) including cardioprotective, neuroprotective, and antihypertension activities have attracted many studies to bring it into clinical use. RUT is phytochemically derived from plants such as apples and tea. It is poorly soluble and very sensible to acidic pH in the stomach environment which leads to conceded oral bioavailability. In contrast, RUT is better soluble in basic environment, thus, encapsulating RUT within enteric microparticles (RUT-MP) using casein (CAS) resolved such problems. The encapsulation by spray-drying employed sugars (lactose, sucrose, and maltodextrin) as bulking agents and for stabilization of the amorphous drug. The developed RUT-MP formulations were prepared in two groups i.e., lower and higher RUT concentrations. The solid states were studied by X-ray diffraction (XRD), differential thermal analysis (DTA) and scanning electron microscopy (SEM). Solubility tests were also carried out on the samples to examine the outcome of the engineered physical modification. The results showed that the RUT-MPs were spherical in morphology. The RUT was transformed into amorphous structure as suggested by the XRD and DTA results indicating that RUT was molecularly dispersed in the RUT-MP. There were no phase separations that occurred as confirmed by the DTA data. Solubility tests carried out on the RUT-MPs showed that the encapsulation with CAS in group with higher concentration of RUT prevented the drug against recovery of the crystallinity and phase separations. The solubility test revealed various substantial enhancements of RUT solubility of the RUT-MPs at pH 7.0. The highest enhancement of RUT solubility was 191,5-fold, with respect to pure RUT. The presence of sugars was beneficial as they improved the yield percentage and might have contributed to the prevention of nano-crystal aggregation which made them a determining aspect for the successful application of spray-dried encapsulation.

Correlations between in vitro gastrointestinal digestion of β-galactosidase/carboxymethylchitosan-silica dosage powder and its physicochemical properties

Oral administration of β-galactosidase, which alleviate lactose intolerance symptoms, is challenging due to its instability throughout the gastrointestinal tract. The objective of this work was to make correlations between the in-vitro digestion and chemical characteristics of a β-galactosidase/carboxymethylchitosan-silica biocatalyst powder. This was obtained by a one-pot silica gel route assisted by carboxymethyl chitosan, using maltose as lyoprotectant. The chemical characterization allowed to understand as was modulated the calcium incorporation, through electrostatic interactions and as maltose protects the enzyme from agglomeration, by vitrification and formation of hydrogen bonds. The formulated biocatalyst could be a complement of silicon and calcium, in turn, it preserves 96 % and 63 % of the enzymatic activity compared with the biocatalyst control (without simulated digestion), in the gastric and intestinal phases, respectively. This activity was even greater than that observed in the commercial products evaluated in these phases. Likewise, the biocatalyst obtained retained its activity after 12 months of storage at 25 °C and it did not present cytotoxicity in cells derived from human colon epithelial mucosa (NCM460) under the conditions and concentrations evaluated. These results make this biocatalyst in an excellent candidate for release of this enzyme. Therefore, it could be useful for lactose-intolerant people.

Continuous flow fabrication of Fmoc-cysteine based nanobowl infused core-shell like microstructures for pH switchable on-demand anti-cancer drug delivery

Asymmetric nanostructures such as nanobowls (NBs) can exhibit superior drug delivery performances owing to their concave structure and interior asymmetric cavities. Here, we present a facile one-step method for the fabrication of NB like structures from a mere single amino acid mimetic, N-(9-fluorenylmethoxycarbonyl)-S-triphenylmethyl-l-cysteine following continuous-flow microfluidics enabled supramolecular self-assembly. Following fabrication, NBs were further infused into a vesicular shell consisting of the amino acid N-(tert-butoxycarbonyl)-S-triphenylmethyl-l-cysteine, carrying dual acid labile groups, the triphenylmethyl and the tert-butyloxycarbonyl groups. The NB infused core-shell like microstructures formed after the shell coating will now be addressed as NB-shells. Presence of pH-responsive shells bestowed the core-shell NB like structures with the ability to actively tune their surface pore opening and closing in response to environmental pH switch. To illustrate the potential use of the NB-shells in the field of anticancer drug delivery, the particles were loaded with doxorubicin (Dox) with an encapsulation efficiency of 42% and Dox loaded NB-shells exhibited enhanced efficacy in C6 glioma cells. Additionally, when tested in an animal model of glioblastoma, the nanoformulations demonstrated significantly higher retardation of tumour growth as compared to free Dox. Thus, this work strives to provide a new research area in the development of well turned-out and neatly fabricated pH switchable on/off anti-cancer drug delivery systems with significant translational potential.

Stimulus-Responsive Sequential Release Systems for Drug and Gene Delivery

In recent years, a range of studies have been conducted with the aim to design and characterize delivery systems that are able to release multiple therapeutic agents in controlled and programmed temporal sequences, or with spatial resolution inside the body. This sequential release occurs in response to different stimuli, including changes in pH, redox potential, enzyme activity, temperature gradients, light irradiation, and by applying external magnetic and electrical fields. Sequential release (SR)-based delivery systems, are often based on a range of different micro- or nanocarriers and may offer a silver bullet in the battle against various diseases, such as cancer. Their distinctive characteristic is the ability to release one or more drugs (or release drugs along with genes) in a controlled sequence at different times or at different sites. This approach can lengthen gene expression periods, reduce the side effects of drugs, enhance the efficacy of drugs, and induce an anti-proliferative effect on cancer cells due to the synergistic effects of genes and drugs. The key objective of this review is to summarize recent progress in SR-based drug/gene delivery systems for cancer and other diseases.

Challenges and Recent Progress in Oral Drug Delivery Systems for Biopharmaceuticals

Routes of drug administration and the corresponding physicochemical characteristics of a given route play significant roles in therapeutic efficacy and short term/long term biological effects. Each delivery method has favorable aspects and limitations, each requiring a specific delivery vehicles design. Among various routes, oral delivery has been recognized as the most attractive method, mainly due to its potential for solid formulations with long shelf life, sustained delivery, ease of administration and intensified immune response. At the same time, a few challenges exist in oral delivery, which have been the main research focus in the field in the past few years. The present work concisely reviews different administration routes as well as the advantages and disadvantages of each method, highlighting why oral delivery is currently the most promising approach. Subsequently, the present work discusses the main obstacles for oral systems and explains the most recent solutions proposed to deal with each issue.