Among the advantages are rapid uptake and avoiding first-pass hepatic metabolism. Polyacrylic acid hydrogels have been extensively studied as mucoadhesive systems. Encyclopedia of Pharmaceutical Technology. Local adverse effects 1 h after the treatment were significantly less frequent among the mucoadhesive patch patients compared with the oral solution patients. Besides molecular weight or chain length, spatial conformation of a polymer is also important. Rheological characterization of bioadhesive binary polymeric systems designed as platforms for drug delivery implants. There is a new class of substances being identified as bioadhesive.
The chamber with the mucous membrane is raised until it comes into contact with the microsphere and, after contact time, is lowered back to the initial position Mathiowitz, Chickering, Lehr, The texture analyzer, operating in tensile test mode and coupled with a sliding lower platform, was also used to determine peel strength of similar formulations [ Figure 4 ]. Gamma scintigraphy allows the immediate visualization of all the formulation transit, with low exposure of the subjects to radiation. Recently, there has been a growing interest in alternative delivery system designs. Aminolevulic acid ALA is commonly delivered to the vulva using creams or solutions, which are covered with an occlusive dressing. Mucoadhesive polymers have numerous hydrophilic groups, such as hydroxyl, carboxyl, amide, and sulfate.
In frequency sweep, stress is maintained constant. Fentanyl, PVP[ 59 ].
For less organized systems, dynamic moduli are dependent on the frequency and a slope is observed. Based on results, a force-distance curve can be plotted which yields the force required to detach the mucin tnesis from the surface with the formulation Bruschi et al. Gastrointestinal transit and mucoadhesive characteristics of complexation hydrogels in rats. Electronic theory is based on the premise that both mucoadhesive and biological materials possess opposing electrical mucoadhessive.
Gene transfer is considered to be a promising alternative for the treatment of several chronic diseases that affect the ocular surface. Techniques utilizing gut sac of rats.
Mucoadhesion may be affected by a number of factors, including hydrophilicity, molecular weight, cross-linking, swelling, pH, and the concentration of the active polymer.
It has been shown that the addition of mucoadhesive polymers to ocular films reduced film movement across the eye, minimizing ocular irritation and burning sensations. Vaginal gels are semisolid polymeric matrices comprising small amounts of solid, dispersed in relatively large amounts of liquid and have been used in systems for microbicides, contraceptives, labor inducers, and other substances.
Comprised of three distinct layers — epithelium, basement membrane, and connective tissues. In tensile and shear experiments, the stress is uniformly distributed over the adhesive joint, whereas in the peel strength stress is focused at the edge of the joint.
Mucoadhesive drug delivery systems
Mucoadhesion strength can also be measured in terms of shear strength. Adsorption theory According to the adsorption theory, the mucoadhesive device adheres to the mucus by secondary chemical interactions, such as in van der Waals and hydrogen bonds, electrostatic attraction deliver hydrophobic interactions.
For example, a partially hydrated polymer can be adsorbed by the substrate because of the attraction by the surface water Lee, Park, Robinson et al. Encyclopedia of Pharmaceutical Technology. Polyacrylic acid hydrogels have been extensively jucoadhesive as mucoadhesive systems. The approximate p K a for the poly acrylic acid family of polymers is between 4 and 5.
Preparation of thiomer microparticles and in vitro evaluation of parameters influencing their mucoadhesive properties. For such investigations, a resolution at micro- or nanometric level is needed.
The deilvery must spread over the substrate to initiate close contact and increase surface contact, promoting the diffusion of its chains within the mucus. Increase in compression force resulted in a decreased in vitro and in vivo drug release while giving the best in vivo mucoadhesive and hydration time.
The use of mucoadhesive polymers in ocular drug delivery.
The bioadhesion force, Fis determined by equation Many bioadhesives used in drug delivery are polyanions possessing carboxylic deliivery functionalities. Permeability barrier property of oral mucosa due to intercellular materials derived from membrane-coating granules. Nevertheless, three main testing modes are recognized — tensile test, shear strength, and peel strength.
The reproducibility of rheological measures is reasonably good, since the measures are taken on already balanced mixtures; composition, pH, and temperature can be carefully controlled and therefore fewer repetitions are necessary to obtain statistically significant data.
Lectins are immunogenic vegetal glycoproteins that specifically recognize sugar molecules. After the experiment, the magnetic current is converted into force and the computer calculates the parameters of adhesion. The mucous site most used fhesis drug administration and absorption is gastrointestinal Junginger, Thanou, Verhoef,but other routes, including nasal, ocular, buccal, vaginal, rectal, oral, and periodontal have also been studied Bruschi et.
For linear polymers, mucoadhesion increases with molecular weight, but the same relationship mucoadhesjve not hold for non-linear polymers.
Mucoadhesive drug delivery systems
An in vitro and in vivo Study. Mucoadhesive drug delivery systems. Factors Affecting Mucoadhesion Mucoadhesion may be affected by a number of factors, including hydrophilicity, molecular weight, cross-linking, swelling, pH, and the concentration of the active polymer. Nasal delivery of deliveru and peptide therapeutics can be compromised by the brief residence time at this mucosal surface.