Mucoadhesive delivery system controlled release

Additionally, a mucoadhesive delivery system designed for controlled release of active compounds should be localized at specific sites of administration and absorption, and should prolong the residence time of the active compound at the site of administration to permit, if possible for one daily dosing. 

The eoneept of mueoadhesion in drug delivery was introduced in the field of controlled-release drug delivery systems in the early 1980s [2,3]. Thereafter, several researchers have focused on the investigations of the interfacial phenomena of mucoadhesive hydrogels (and of other type mucoadhesive compounds) with the mucus. Several techniques of studying these interactions were evaluated both in vitro and... 

Bernkop-Schnurch, A., D. Guggi, and Y. Pinter. 2004. Thiolated chitosans development and in vitro evaluation of a mucoadhesive, permeation enhancing oral drug delivery system. J Control Release 94 177. 

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). 

Microparticles and nanoparticles present some advantageous features, namely mucoadhesive properties. They have demonstrated some potential in vaginal drug delivery, particularly in the formulation of delivery systems for vaccines or peptides and proteins [160, 161], Nonetheless, these particles have to be incorporated in adequate carrier systems in order to be delivered. This task has been shown to be complex, it being hard to achieve controlled-release and steady-release profiles. 

Valenta, C., Kast, C. E., Flarich, I., and Bernkop-Schnurch, A. (2001), Development and in vitro evaluation of a mucoadhesive vaginal delivery system for progesterone,/. Controlled Release, 77,323-332. 

Advantages of the oral mucosal route of delivery include its capacity to bypass all the limitations associated with the oral route, ease of administration, relatively low content of enzymes, and adequate vascular drainage. As described in the following sections, most of the limitations of the oral mucosa epithelium arise from its stratified nature and its intercellular content characteristics. Nonetheless, due to its direct connection to systemic circulation, delivery systems could potentially be formulated to show either bolus-like or controlled release profiles for specific therapeutic needs. Polymers used in the development of such delivery systems play a major role in the release profile, permeation enhancement, and the localization of the active in the vicinity of the absorbing mucosa. Among the various uses of polymers in delivery systems, their mucoadhesive nature is the most prominent application in the oral mucosal route and is the main focus of this entry. After describing the physiological considerations in the oral cavity mucosa, this entry will review the literature pertinent to the use of polymers in delivery systems for the oral mucosal route. 

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)... 

Poly(acrylic acid)-cysteine and chitosan-4-thiobulylamidine were evaluated as anionic and cationic polymers for the preparation of a DDS for riboflavin-S -monophosphate sodium salt dihydrate as a model drug. The particles had a mean diameter of 336.5 16.5 and 396.3 17.0 nm and a zeta potential of - 20.0 1.0 and -I- 27.2 0.5 mV, respectively. It was found that glutathione in combination with thiomers has a significant influence for increasing permeation, and that thiolated particles of both anionic and cationic polymers had improved mucoadhesive and controlled release properties. Therefore, they can be potentially applied as gastroretentive delivery systems. ... 

Gavini, E., V. Sanna, C. Juhano, M. C. Bonferoni, and P. Giunchedi. 2002. Mucoadhesive vaginal tablets as veterinary delivery system for the controlled release of an antimicrohial drug, acriflavine. AAPS PharmSciTech 3 (3) E20. 

Chitosan is a promising polymer for colon delivery because it can be biodegraded by the colonic microflora and it has mucoadhesive character. A thorough study has been carried out on chitosan beads obtained by ionotropic gelation with alginate or tripolyphosphate. The aim was to develop, using natural polymers, a controlled release system that would resist the conditions in the stomach and release its drug... 

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