Comparison of the mucoadhesive properties of various polymers

Grabovac, Vjera; Guggi, D.; Bernkop‐Schnürch, Andreas

doi:10.1016/j.addr.2005.07.006

Cited by 384 publications

(212 citation statements)

References 18 publications

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“…Although chitosan loaded into the chewing gum seems to affect salivary PO 4 binding into the mouth acutely, the delayed recovery in serum PO 4 merits further studies. It could be suggested that chitosan, once solubilized into the stomach at acidic pH, could be retained onto the gastrointestinal mucosa for a prolonged time (estimated by some authors to be in the order of 17 to 40 h, depending on pH and the manufacturing process of chitosan), 13 thereby exerting further PO 4 binding. The daily removal of an additional PO 4 load from gastrointestinal fluids could support sevelamer treatment.…”

Section: Discussionmentioning

confidence: 99%

“…In protocol A, low-and middle-viscosity chitosan with a degree of deacetylation Ն75% was tested at pH 6.5, thus mimicking the physiologic pH of the human mouth. In these experimental conditions, chitosan is practically insoluble, and its PO 4 -binding capability relies on the degree of chitosan deacetylation and related polyelectrolytic structure, mucoadhesivity, and retention time onto the gastrointestinal mucosa, as described by Grabovac et al 13 31 P nuclear magnetic resonance ( 31 P-NMR) analysis showed that 2, 10, and 15% (wt/vol) low-viscosity chitosan was able to remove 10, 15, and 20%, respectively, of the 10 mM PO 4 contained in 1ϫ reference PBS (Sigma; corresponding to 10 mM PO 4 in 10 ml [pH 6.5]). Two, 10, and 15% (wt/vol) middle-viscosity chitosan was able to remove 15, 25, and 33%, respectively, of the 10 mM PO 4 contained in 1ϫ PBS solution.…”

Section: In Vitro Characterization Of Chitosan Po 4 Bindingmentioning

confidence: 99%

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Salivary Phosphate-Binding Chewing Gum Reduces Hyperphosphatemia in Dialysis Patients

Savica

Calò

Monardo

et al. 2009

Journal of the American Society of Nephrology

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In uremic patients, hyperphosphatemia is associated with cardiovascular calcification and increased cardiovascular mortality. Despite the use of phosphate binders, only half of hemodialysis (HD) patients achieve recommended serum phosphate levels. A hyperphosphoric salivary content, which correlates linearly with serum phosphate, has been reported in HD patients. We hypothesized that binding salivary phosphate during periods of fasting in addition to using phosphate binders with meals could improve the treatment of hyperphosphatemia. We assessed the phosphate-binding capacity of the natural polymer chitosan by 31 P nuclear magnetic resonance and established that 10 and 20% (wt/vol) middle viscosity chitosan solutions bind 30 and 50% of the phosphate contained in PBS, respectively. Thirteen HD patients with serum phosphate levels Ͼ6.0 mg/dl despite treatment with sevelamer hydrochloride chewed 20 mg of chitosan-loaded chewing gum twice daily for 2 wk at fast in addition to their prescribed phosphate-binding regimen. Salivary phosphate and serum phosphate significantly decreased during the first week of chewing; by the end of 2 wk, salivary phosphate decreased 55% from baseline (73.21 Ϯ 19.19 to 33.19 Ϯ 6.53; P Ͻ 0.00001), and serum phosphate decreased 31% from baseline (7.60 Ϯ 0.91 to 5.25 Ϯ 0.89 mg/dl; P Ͻ 0.00001). Salivary phosphate returned to baseline by day 15 after discontinuing the chewing gum, whereas serum phosphate levels took 30 d to return to baseline. Parathyroid hormone and serum calcium concentrations were not affected by the gum. In conclusion, adding salivary phosphate binding to traditional phosphate binders could be a useful approach for improving treatment of hyperphosphatemia in HD patients.

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Section: Discussionmentioning

confidence: 99%

Section: In Vitro Characterization Of Chitosan Po 4 Bindingmentioning

confidence: 99%

Salivary Phosphate-Binding Chewing Gum Reduces Hyperphosphatemia in Dialysis Patients

Savica

Calò

Monardo

et al. 2009

Journal of the American Society of Nephrology

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“…All these characteristics make thiolated chitosan a promising material for administering peptides and proteins in mucous membrane (Bravo-Osuna et al, 2007). Another study, carried out by Grabovac, Guggi, and Bernkop-Schnürch (2005) established a ranking of the most studied polymers, showing that both thiolated chitosan and polycarbophil are the most mucoadhesive.…”

Section: Second Generation Mucoadhesive Materialsmentioning

confidence: 99%

Mucoadhesive drug delivery systems

Carvalho

Bruschi

Evangelista

et al. 2010

Braz. J. Pharm. Sci.

255

181

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Drug actions can be improved by developing new drug delivery systems, such as the mucoadhesive system. These systems remain in close contact with the absorption tissue, the mucous membrane, releasing the drug at the action site leading to a bioavailability increase and both local and systemic effects. Mucoadhesion is currently explained by six theories: electronic, adsorption, wettability, diffusion, fracture and mechanical. Several in vitro and in vivo methodologies are proposed for studying its mechanisms. However, mucoadhesion is not yet well understood. The aim of this study was to review the mechanisms and theories involved in mucoadhesion, as well as to describe the most-used methodologies and polymers in mucoadhesive drug delivery systems.Uniterms: Mucoadhesion. Bioadhesion. Mucoadhesive systems. Drugs/delivery. O efeito de fármacos pode ser potencializado através do desenvolvimento de novos sistemas de liberação como os sistemas mucoadesivos. Estes sistemas permanecem em contato íntimo com o tecido de absorção, as mucosas, liberando o fármaco no local de ação, com o consequente aumento da biodisponibilidade, podendo promover efeitos locais e sistêmicos. A mucoadesão, atualmente, é explicada por seis teorias, a eletrônica, da adsorção, da molhabilidade, da difusão, da fratura e a mecânica. Para estudar seus mecanismos e quantificá-la, são propostas várias metodologias in vitro e in vivo. Porém, a mucoadesão ainda não é totalmente compreendida. Esse trabalho tem por objetivo revisar os mecanismos e as teorias envolvidas na mucoadesão, além de descrever as metodologias e os polímeros mais utilizados em sistemas mucoadesivos para liberação de fármacos.Unitermos: Mucoadesão. Bioadesão. Sistemas mucoadesivos. Fármacos/liberação.

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“…This work focuses on the development of an inexpensive vaginal gel formulation for the sustained delivery of PYD using GRAS (generally regarded as safe) ingredients-polyacrylic acid (PAA) and a cellulose derivative (15,27,34,38). In particular, hydroxylethyl cellulose (HEC) has been used in several vaginal gel formulations, including the universal placebo gel (32).…”

mentioning

confidence: 99%

Vaginal Microbicide Gel for Delivery of IQP-0528, a Pyrimidinedione Analog with a Dual Mechanism of Action against HIV-1

Mahalingam

Simmons

Ugaonkar

et al. 2011

Antimicrob Agents Chemother

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Pyrimidinediones, a novel class of compounds, have previously been shown to possess antiviral activity at nanomolar concentrations. One member of this class of compounds, IQP-0528, was selected as the lead molecule for formulation development owing to its stability at physiologically relevant conditions, wide therapeutic window, and antiviral activity in the nanomolar range. Here, we report the development of two vaginal gels-3.0% hydroxyethyl cellulose (HEC) formulation and a 0.65% Carbopol formulation-for the sustained delivery of IQP-0528. Stability studies under accelerated conditions confirmed the chemical stability of IQP-0528 and mechanical stability of the gel formulation for 3 months. In vitro release studies revealed that diffusion-controlled release of IQP-0528 occurred over 6 h, with an initial lag time of approximately 1 h. Based on the drug release profile, the 3.0% HEC gel was selected as the lead formulation for safety and activity evaluations. The in vitro and ex vivo safety evaluations showed no significant loss in cell viability or significant inflammatory response after treatment with a 3.0% HEC gel containing 0.25% IQP-0528. In an in vitro HIV-1 entry inhibition assay, the lead formulation showed an 50% effective concentration of 0.14 g/ml for gel in culture media, which corresponds to ϳ0.001 M IQP-0528. The antiviral activity was further confirmed by using polarized cervical explants, in which the formulation showed complete protection against HIV infection. In summary, these results are encouraging and warrant further evaluation of IQP-0528 gel formulations in in vivo models, as well as the development of alternative formulations for the delivery of IQP-0528 as a microbicide.

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Comparison of the mucoadhesive properties of various polymers

Cited by 384 publications

References 18 publications

Salivary Phosphate-Binding Chewing Gum Reduces Hyperphosphatemia in Dialysis Patients

Salivary Phosphate-Binding Chewing Gum Reduces Hyperphosphatemia in Dialysis Patients

Mucoadhesive drug delivery systems

Vaginal Microbicide Gel for Delivery of IQP-0528, a Pyrimidinedione Analog with a Dual Mechanism of Action against HIV-1

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