Mucoadhesion-Based Delivery System

Hongyi, Q. Wenwen, C. Chunyan, H. Li, L. Churning, C. Wenmin, L. Chunjie, W. Development of a poloxamer analogs/carbopol-based in-situ gelling and mucoadhesive ophthalmic delivery system for puerarin. 7nf. J. Pharm. 2007,337 (1-2), 178-187. 

Conventional vaginal delivery systems include tablets, foams gels, suspensions, and pessaries. Mucoadhesive gel formulations based on polycarbophil have been reported to remain 3 to 4 days at the vaginal tissue, providing an excellent vehicle for the delivery of progesterone and nonoxynol-9 [66]. 

More recently, increasing research attention has focused upon the use of mucoadhesive delivery systems in which the biopharmaceutical is formulated with/encapsulated in molecules which interact with the intestinal mucosa membranes. The strategy is obviously to retain the drug at the absorbing surface for a prolonged period. Non-specific (charge-based) interactions can be achieved by the use of polyacrylic acid, while more biospecific interactions are achieved by using selected lectins or bacterial adhesion proteins. Despite intensive efforts, however, the successful delivery of biopharmaceuticals via the oral route remains some way off. 

Conventional systems do not offer sufficient flexibility in controlling drug-release rate and sustaining the release over time periods extending from days to months. Therefore specific modified release vaginal delivery systems are continuously under development and are based on mucoadhesive systems. Penetration enhancement may represent a necessary feature for certain delivery systems, particularly when the absorption regards a macromolecule (such as a peptide or a protein). 

Different drug delivery systems have been proposed for vaginal delivery of peptides and proteins. The first one was a mucoadhesive gel based on polyacrylic acid intended for vaginal administration of insulin [96]. More recently, microparticulate systems such as starch and hyaluronan ester (HYAFF) microspheres have been proposed for vaginal delivery of insulin... 

Design of Retentive Delivery System Based on Adhesion Mucoadhesive Systems... 

Some of the most promising data on gastroretentive delivery systems using bioadhesion have resulted from the use of acrylate-based as well as chitosan-based polymers. Poly(acrylates) have been shown to have significant mucoadhesive properties in contact with intestinal mucosal tissues.104 122 135 Longer et al.136 demonstrated successful reduction in the... 

Neilson LS, Schubert L, Hansen J. Bioadhesive drug delivery systems. 1. Characterization of mucoadhesive properties of systems based on glyceryl monooleate and glycerol monolinoleate. Eur ] Pharm Set 1998 6(9) 231-239. 

Davidovich-Pinhas, M., Harari, O., Bianco-Peled, H. Evaluating the mucoadhesive properties of drug delivery systems based on hydrated thiolated alginate. J. Controlled Release 136, 38 (2009)... 

Reduction of the disulfide bond in the thiol-rich environment, resulting in the release of the entrapped protein, was also the working principle of another intracellular protein delivery system. The DDS was based on linear polyamidoamines (PAAs) that formed a PEC with negatively charged human serum albumin (HSA). The PEC showed mucoadhesive properties and released the immobilized HSA under intracellular conditions due to the cleavage of the disulfide bonds, while the complex was stable under extracellular conditions. This resulted in enhanced uptake by exposed human-derived intestinal Caco-2/TC7 cells and HT29-MTX mucus/ secreting cells. 

CS-based thiolated microgels with an average size of 18 pm have been prepared either by water-in-oil (w/o) emulsification solvent evaporation" or by precipitation-miaonization technique." For thiolation, 2-iminothiolane (Trout s rea nt) was covalently linked to CS via an amidine bond leading to the formation of CS-4-thiobutylamidine. Such polymers show higher mucoadhesive and permeation-enhandng properties than unmodified CS," " which makes them ideal precursors for nasal or oral dmg delivery systems. 

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