Nanotechnology-based mucoadhesive and mucus-penetrating drug-delivery systems for transbuccal drug delivery

Mucosa-penetrating liposomes for esophageal local drug delivery

Local drug delivery to the esophagus is hampered by rapid transit time and poor permeability of the mucosa. If some strategies aimed to improve the residence time have been proposed, non-invasive approaches to increase the drug penetration in the mucosa have not been described so far. Herein, we designed mucosa-penetrating liposomes to favor the penetration and retention of curcumin (CURC) in the esophagus. A novel mucosa penetrating peptide (MPP), SLENKGP, was selected by Phage Display and conjugated to pegylated liposomes at different PEG and MPP's surface densities. Pegylation assured a long residence time of liposomes (at least 30 min) in the esophagus in vivo, but it did not favor the penetration of CURC in the mucosa. MPP-decorated liposomes instead delivered a significant higher amount of CURC in the mucosa compared to naked pegylated liposomes. Confocal microscopy studies showed that naked pegylated liposomes remain confined in the superficial layers of the mucosa whereas MPP-decorated liposomes penetrate the whole epithelium. In vitro, MPP reduced the interaction of PEG with mucin, meanwhile favoring the paracellular penetration of liposomes across epithelial cell multilayers. In conclusion, pegylated liposomes represent a valid approach to target the esophagus and the surface functionalization with MPP enhances their penetration in the mucosa.

Biopolymer Drug Delivery Systems for Oromucosal Application: Recent Trends in Pharmaceutical R&D

Oromucosal drug delivery, both local and transmucosal (buccal), is an effective alternative to traditional oral and parenteral dosage forms because it increases drug bioavailability and reduces systemic drug toxicity. The oral mucosa has a good blood supply, which ensures that drug molecules enter the systemic circulation directly, avoiding drug metabolism during the first passage through the liver. At the same time, the mucosa has a number of barriers, including mucus, epithelium, enzymes, and immunocompetent cells, that are designed to prevent the entry of foreign substances into the body, which also complicates the absorption of drugs. The development of oromucosal drug delivery systems based on mucoadhesive biopolymers and their derivatives (especially thiolated and catecholated derivatives) is a promising strategy for the pharmaceutical development of safe and effective dosage forms. Solid, semi-solid and liquid pharmaceutical formulations based on biopolymers have several advantageous properties, such as prolonged residence time on the mucosa due to high mucoadhesion, unidirectional and modified drug release capabilities, and enhanced drug permeability. Biopolymers are non-toxic, biocompatible, biodegradable and may possess intrinsic bioactivity. A rational approach to the design of oromucosal delivery systems requires an understanding of both the anatomy/physiology of the oral mucosa and the physicochemical and biopharmaceutical properties of the drug molecule/biopolymer, as presented in this review. This review summarizes the advances in the pharmaceutical development of mucoadhesive oromucosal dosage forms (e.g., patches, buccal tablets, and hydrogel systems), including nanotechnology-based biopolymer nanoparticle delivery systems (e.g., solid lipid particles, liposomes, biopolymer polyelectrolyte particles, hybrid nanoparticles, etc.).

A Synthetic Model of the Mucosa for Oral Penetration Studies

The main objective of this study is the evaluation of the use of a synthetic membrane, Nuclepore, as a model for permeation studies through sublingual mucosa. The permeability of two types of membranes, porcine sublingual oral mucosa and a synthetic Nuclepore membrane, to water was compared. Moreover, the water permeability of membranes modified with waterproofing formulations was measured to study their ability to protect against the penetration of viruses, toxins, etc. A relatively high correlation (R2 0.88) was obtained between the transmucosal water loss (TMWL) values of the artificial membrane and the mucosa. These results support the possible use of this synthetic membrane in the screening of the water permeability of formulations. In addition, studies of the permeation of different actives, drugs, and biocides through the two membranes were carried out, and these results were compared with their skin permeation data. The synthetic membrane does not seem to discern between compounds in terms of permeability. However, the permeation of caffeine through intact or modified membranes incorporating waterproofing formulations presents similar permeation profiles through the synthetic membrane and mucosa. The results from these assays should lend support to the use of this synthetic membrane when screening formulations to be applied in oral penetration studies.

Nanoparticle-mediated active and passive drug targeting in oral squamous cell carcinoma: current trends and advances

Oral squamous cell carcinoma (OSCC) is an invasive and highly malignant cancer with significant morbidity and mortality. Existing treatments including surgery, chemotherapy and radiation have poor overall survival rates and prognosis. The intended therapeutic effects of chemotherapy are limited by drug resistance, systemic toxicity and adverse effects. This review explores advances in OSCC treatment, with a focus on lipid-based platforms (solid lipid nanoparticles, nanostructured lipid carriers, lipid-polymer hybrids, cubosomes), polymeric nanoparticles, self-assembling nucleoside nanoparticles, dendrimers, magnetic nanovectors, graphene oxide nanostructures, stimuli-responsive nanoparticles, gene therapy, folic acid receptor targeting, gastrin-releasing peptide receptor targeting, fibroblast activation protein targeting, urokinase-type plasminogen activator receptor targeting, biotin receptor targeting and transferrin receptor targeting. This review also highlights oncolytic viruses as OSCC therapy candidates.