Oligonucleotide Delivery across the Caco-2 Monolayer: The Design and Evaluation of Self-Emulsifying Drug Delivery Systems (SEDDS)

Potential of the Nano-Encapsulation of Antioxidant Molecules in Wound Healing Applications: An Innovative Strategy to Enhance the Bio-Profile

Naturally available antioxidants offer remarkable medicinal applications in wound healing. However, the encapsulation of these phytoactive moieties into suitable nano-scale drug delivery systems has always been challenging due to their inherent characteristics, such as low molecular weight, poor aqueous solubility, and inadequate skin permeability. Here, we provide a systematic review focusing on the major obstacles hindering the development of various lipid and polymer-based drug transporters to carry these cargos to the targeted site. Additionally, this review covers the possibility of combining the effects of a polymer and a lipid within one system, which could increase the skin permeability threshold. Moreover, the lack of suitable physical characterization techniques and the challenges associated with scaling up the progression of these nano-carriers limit their utility in biomedical applications. In this context, consistent progressive approaches for addressing these shortcomings are introduced, and their prospects are discussed in detail.

Enhancing photodynamic and radionuclide therapy by small interfering RNA (siRNA)-RAD51 transfection via self-emulsifying delivery systems (SNEDDS)

BACKGROUND AIMS

Gene-silencing by small interfering RNA (siRNA) is an attractive therapy to regulate cancer death, tumor recurrence or metastasis. Because siRNAs are easily degraded, it is necessary to develop transport and delivery systems to achieve efficient tumor targeting. Self-nanoemulsifying systems (SNEDDS) have been successfully used for pDNA transport and delivery, so they may be useful for siRNA. The aim of this work is to introduce siRNA-RAD51 into a SNEDDS prepared with Phospholipon-90G, Labrafil-M1944-CS and Cremophor-RH40 and evaluate its efficacy in preventing homologous recombination of DNA double-strand breaks caused by photodynamic therapy (PDT) and ionizing radiation (IR).

METHODS

The siRNA-RAD51 was loaded into SNEDDS using chitosan. Transfection capacity was estimated by comparison with Lipofectamine-2000.

RESULTS

SNEDDS(siRNA-RAD51) induced gene silencing effect on the therapies evaluated by cell viability and clonogenic assays using T47D breast cancer cells.

CONCLUSIONS

SNEDDS(siRNA-RAD51) shown to be an effective siRNA-delivery system to decrease cellular resistance in PDT or IR.

Innovations in Nanoemulsion Technology: Enhancing Drug Delivery for Oral, Parenteral, and Ophthalmic Applications

Nanoemulsions (NEs) are submicron-sized heterogeneous biphasic liquid systems stabilized by surfactants. They are physically transparent or translucent, optically isotropic, and kinetically stable, with droplet sizes ranging from 20 to 500 nm. Their unique properties, such as high surface area, small droplet size, enhanced bioavailability, excellent physical stability, and rapid digestibility, make them ideal for encapsulating various active substances. This review focuses on recent advancements, future prospects, and challenges in the field of NEs, particularly in oral, parenteral, and ophthalmic delivery. It also discusses recent clinical trials and patents. Different types of in vitro and in vivo NE characterization techniques are summarized. High-energy and low-energy preparation methods are briefly described with diagrams. Formulation considerations and commonly used excipients for oral, ocular, and ophthalmic drug delivery are presented. The review emphasizes the need for new functional excipients to improve the permeation of large molecular weight unstable proteins, oligonucleotides, and hydrophilic drugs to advance drug delivery rapidly.

Comparison of the liquisolid technique and co-milling for loading of a poorly soluble drug in inorganic porous excipients

Drug loading into mesoporous carriers may help to improve the dissolution of poorly aqueous-soluble drugs. However, both preparation method and carrier properties influence loading efficiency and drug release. Accordingly, this study aimed to compare two preparation methods: formulation into liquisolid systems (LSS) and co-milling for their efficiency in loading the poorly soluble model drug cyclosporine A (CyA) into mesoporous magnesium aluminometasilicate Neusilin® US2 (NEU) or functionalized calcium carbonate (FCC). Scanning electron microscopy was used to visualize the morphology of the samples and evaluate the changes that occurred during the drug loading process. The solid-state characteristics and physical stability of the formulations, prepared at different drug concentrations, were determined using X-ray powder diffraction. In vitro release of the drug was evaluated in biorelevant media simulating intestinal fluid. The obtained results revealed improved drug release profiles of the formulations when compared to the milled (amorphous) CyA alone. The dissolution of CyA from LSS was faster in comparison to the co-milled formulations. Higher drug release was achieved from NEU than FCC formulations presumably due to the higher pore volume and larger surface area of NEU.

Atorvastatin-loaded pro-nanolipospheres with ameliorated oral bioavailability and antidyslipidemic activity

Despite significant advances in oral drug delivery technologies, many drugs are prone to limited oral bioavailability due to biological barriers that hinder drug absorption. Pro-nanolipospheres (PNL) are a form of delivery system that can potentiate the oral bioavailability of poorly water-soluble drugs through a variety of processes, including increased drug solubility and protecting them from degradation by intestinal or hepatic first-pass metabolism. In this study, pro-nanolipospheres were employed as a delivery vehicle for improving the oral bioavailability of the lipophilic statin, atorvastatin (ATR). Various ATR-loaded PNL formulations, composed of various pharmaceutical ingredients, were prepared by the pre-concentrate method and characterized by determining particle size, surface charge, and encapsulation efficiency. An optimized formula (ATR-PT PNL) showing the smallest particle size, highest zeta potential, and highest encapsulation efficiency was selected for further in vivo investigations. The in vivo pharmacodynamic experiments demonstrated that the optimized ATR-PT PNL formulation exerted a potent hypolipidemic effect in a Poloxamer® 407-induced hyper-lipidaemia rat model by restoring normal cholesterol and triglyceride serum levels along with alleviating serum levels of LDL while elevating serum HDL levels, compared to pure drug suspensions and marketed ATR (Lipitor®). Most importantly, oral administration of the optimized ATR-PT PNL formulation showed a dramatic increase in ATR oral bioavailability, as evinced by a 1.7- and 3.6-fold rise in systemic bioavailability when compared with oral commercial ATR suspensions (Lipitor®) and pure drug suspension, respectively. Collectively, pro-nanolipospheres might represent a promising delivery vehicle for enhancing the oral bioavailability of poorly water-soluble drugs.

Nanocarriers for delivery of siRNA as gene silencing mediator

The term nanocarrier refers to sub-micrometric particles of less than 100 nm, designed to transport, distribute, and release nanotechnology-based drug delivery systems. siRNA therapy is a novel strategy that has great utility for a variety of treatments, however naked siRNA delivery has not been an effective strategy, resulting in the necessary use of nanocarriers for delivery. This review aims to highlight the versatility of carriers based on smart drug delivery systems. The nanocarriers based on nanoparticles as siRNA DDS have provided a set of very attractive advantages related to improved physicochemical properties, such as high surface-to-volume ratio, versatility to package siRNA, provide a dual function to both protect extracellular barriers that lead to elimination and overcome intracellular barriers limiting cytosolic delivery, and possible chemical modifications on the nanoparticle surface to improve stability and targeting. Lipid and polymeric nanocarriers have proven to be stable, biocompatible, and effective in vitro, further exploration of the development of new nanocarriers is needed to obtain safe and biocompatible tools for effective therapy.

Oral delivery of therapeutic peptides and proteins: Technology landscape of lipid-based nanocarriers

The oral administration of therapeutic peptides and proteins is favoured from a patient and commercial point of view. In order to reach the systemic circulation after oral administration, these drugs have to overcome numerous barriers including the enzymatic, sulfhydryl, mucus and epithelial barrier. The development of oral formulations for therapeutic peptides and proteins is therefore necessary. Among the most promising formulation approaches are lipid-based nanocarriers such as oil-in-water nanoemulsions, self-emulsifying drug delivery systems (SEDDS), solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), liposomes and micelles. As the lipophilic character of therapeutic peptides and proteins can be tremendously increased such as by the formation of hydrophobic ion pairs (HIP) with hydrophobic counter ions, they can be incorporated in the lipophilic phase of these carriers. Since gastrointestinal (GI) peptidases as well as sulfhydryl compounds such as glutathione and dietary proteins are too hydrophilic to enter the lipophilic phase of these carriers, the incorporated therapeutic peptide or protein is protected towards enzymatic degradation as well as unintended thiol/disulfide exchange reactions. Stability of lipid-based nanocarriers towards lipases can be provided by the use to excipients that are not or just poorly degraded by these enzymes. Nanocarriers with a size <200 nm and a mucoinert surface such as PEG or zwitterionic surfaces exhibit high mucus permeating properties. Having reached the underlying absorption membrane, lipid-based nanocarriers enable paracellular and lymphatic drug uptake, induce endocytosis and transcytosis or simply fuse with the cell membrane releasing their payload into the systemic circulation. Numerous in vivo studies provide evidence for the potential of these delivery systems. Within this review we provide an overview about the different barriers for oral peptide and protein delivery, highlight the progress made on lipid-based nanocarriers in order to overcome them and discuss strengths and weaknesses of these delivery systems in comparison to other technologies.

Formulation and Evaluation of Self-Nanoemulsifying Drug Delivery System Derived Tablet Containing Sertraline

Being a biopharmaceutics classification system class II drug, the absorption of sertraline from the gut is mainly limited by its poor aqueous solubility. The objective of this investigation was to improve the solubility of sertraline utilizing self-nanoemulsifying drug delivery systems (SNEDDS) and developing it into a tablet dosage form. Ternary phase diagrams were created to identify nanoemulsion regions by fixing oil (glycerol triacetate) and water while varying the surfactant (Tween 80) and co-surfactant (PEG 200) ratio (S_mix). A three-factor, two-level (2³) full factorial design (batches F1–F8) was utilized to check the effect of independent variables on dependent variables. Selected SNEDDS (batch F4) was solidified into powder by solid carrier adsorption method and compressed into tablets. The SNEDDS-loaded tablets were characterized for various pharmaceutical properties, drug release and evaluated in vivo in Wistar rats. A larger isotropic region was noticed with a S_mix ratio of 2:1 and the nanoemulsion exhibited good stability. Screening studies’ data established that all three independent factors influence the dependent variables. The prepared tablets displayed optimal pharmaceutical properties within acceptable limits. In vitro sertraline release demonstrated from solid SNEDDS was statistically significant (p < 0.0001) as compared to pure sertraline. Differential Scanning Calorimetry and X-Ray Diffraction data established the amorphous state of the drug in SNEDDS formulation, while FTIR spectra indicate the compatibility of excipients and drug. Pharmacokinetic evaluation of the SNEDDS tablet demonstrated significant increment (p < 0.0001) in AUC_0-α (~5-folds), C_max (~4-folds), and relative bioavailability (386%) as compared to sertraline suspension. The current study concludes that the solid SNEDDS formulation could be a practicable and effective strategy for oral therapy of sertraline.

Sorafenib Repurposing for Ophthalmic Delivery by Lipid Nanoparticles: A Preliminary Study

Uveal melanoma is the second most common melanoma and the most common intraocular malignant tumour of the eye. Among various treatments currently studied, Sorafenib was also proposed as a promising drug, often administered with other compounds in order to avoid resistance mechanisms. Despite its promising cellular activities, the use of Sorafenib by oral administration is limited by its severe side effects and the difficulty to reach the target. The encapsulation into drug delivery systems represents an interesting strategy to overcome these limits. In this study, different lipid nanoparticulate formulations were prepared and compared in order to select the most suitable for the encapsulation of Sorafenib. In particular, two solid lipids (Softisan or Suppocire) at different concentrations were used to produce solid lipid nanoparticles, demonstrating that higher amounts were able to achieve smaller particle sizes, higher homogeneity, and longer physical stability. The selected formulations, which demonstrated to be biocompatible on Statens Seruminstitut Rabbit Cornea cells, were modified to improve their mucoadhesion, evaluating the effect of two monovalent cationic lipids with two lipophilic chains. Sorafenib encapsulation allowed obtaining a sustained and prolonged drug release, thus confirming the potential use of the developed strategy to topically administer Sorafenib in the treatment of uveal melanoma.

Comparison of Cellular Monolayers and an Artificial Membrane as Absorptive Membranes in the in vitro Lipolysis-permeation Assay

Permeation across Caco-2 cells in lipolysis-permeation setups can predict the rank order of in vivo drug exposure obtained with lipid-based formulations (LBFs). However, Caco-2 cells require a long differentiation period and do not capture all characteristics of the human small intestine. We therefore evaluated two in vitro assays with artificial lecithin-in-dodecane (LiDo) membranes and MDCK cells as absorptive membranes in the lipolysis-permeation setup. Fenofibrate-loaded LBFs were used and the results from the two assays compared to literature plasma concentrations in landrace pigs administered orally with the same formulations. Aqueous drug concentrations, supersaturation, and precipitation were determined in the digestion chamber and drug permeation in the receiver chamber. Auxiliary in vitro parameters were assessed, such as permeation of the taurocholate, present in the simulated intestinal fluid used in the assay, and size of colloidal structures in the digestion medium over time. The LiDo membrane gave a similar drug distribution as the Caco-2 cells and accurately reproduced the equivalent rank-order of fenofibrate exposure in plasma. Permeation of fenofibrate across MDCK monolayers did not, however, reflect the in vivo exposure rankings. Taurocholate flux was negligible through either membrane. This process was therefore not considered to significantly affect the in vitro distribution of fenofibrate. We conclude that the artificial LiDo membrane is a promising tool for lipolysis-permeation assays to evaluate LBF performance.