Gamma-scintigraphy as a novel method to study the distribution and retention of a bioadhesive vaginal delivery system in sheep

Richardson, Julie; Whetstone, Joanne; Fisher, A. N.; Watts, Peter; Farraj, Nidal F.; Hinchcliffe, Michael; Benedetti, L.; Illum, Lisbeth

doi:10.1016/0168-3659(96)01451-4

Cited by 40 publications

(18 citation statements)

References 10 publications

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“…Dimensions of the vaginal cavity of the sheep can be outlined and imaged using labeled gellan gum and the data collected is subsequently used to compare the distribution of radiolabelled HYAFF formulations. The retention of mucoadhesive-radiolabelled microspheres based on HYAFF polymer was found 54) to be more for the dry powder formulation than for the pessary formulation after 12 h of administration to vaginal epithelium.…”

Section: In Vivo Techniquesmentioning

confidence: 99%

Mucoadhesive Microspheres for Controlled Drug Delivery

Chowdary

Rao

2004

Biological & Pharmaceutical Bulletin

155

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Mucoadhesion is a topic of current interest in the design of drug delivery systems. Mucoadhesive microspheres exhibit a prolonged residence time at the site of application or absorption and facilitate an intimate contact with the underlying absorption surface and thus contribute to improved and/or better therapeutic performance of drugs. In recent years such mucoadhesive microspheres have been developed for oral, buccal, nasal, ocular, rectal and vaginal routes for either systemic or local effects. The objective of this article is review the principles underlying the development and evaluation of mucoadhesive microspheres and the research work carried out on these systems.

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Section: In Vivo Techniquesmentioning

confidence: 99%

Mucoadhesive Microspheres for Controlled Drug Delivery

Chowdary

Rao

2004

Biological & Pharmaceutical Bulletin

155

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“…Some methods assess the residence time at the application site using gamma scintigraphy (Davis 1986;Harris et al 1990;Richardson et al 1996;Brown et al 1997;Soane et al 1999Soane et al , 2001Chatterton et al 2004) or dyes (Nakamura et al 1996), while others involve measurement of the transit time using radioisotopes (Ch'ng et al 1985; Riley et al 2001). The successful use of tracers added to the formulation relies upon the properties of the vehicle remaining unchanged and, therefore, behaving in a manner that is identical to that in the absence of the tracer so that the results obtained are a genuine reflection of the residence time of the dosage form.…”

Section: In-vivo Methodsmentioning

confidence: 99%

“…The retention of microspheres made from a benzyl ester of hyaluronic acid (HYAFF) was studied using gamma scintigraphy in sheep (Richardson et al 1996). The microspheres were either delivered as a dry powder or included in Suppocire BS 2 X pessaries.…”

Section: The Vaginal Routementioning

confidence: 99%

Pharmaceutical applications of mucoadhesion for the non-oral routes

Edsman

Hägerström

2005

Journal of Pharmacy and Pharmacology

155

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The adhesion of pharmaceutical formulations to the mucosal tissue offers the possibility of creating an intimate and prolonged contact at the site of administration. This prolonged residence time can result in enhanced absorption and, in combination with a controlled release of the drug, also improved patient compliance by reducing the frequency of administration. During the almost 30 years over which mucoadhesion has been studied, a considerable amount of knowledge has been gained, and much has been learned about the different mechanisms occurring at the formulationmucus interface and the properties that affect these mechanisms. The in-vivo performance of a dosage form not only depends on the mechanisms occurring at the interface, but also on the properties of the total mucoadhesive complex: the dosage form, the mucosa and the interface between them. A wide variety of methods are used for studying mucoadhesion; some rather similar to the in-vivo situation and some mimicking the interface alone. In this review, the mucus surface, the methods used for the study of mucoadhesion, the different mechanisms involved in mucoadhesion and theories underpinning them have been described. The complexity of mucoadhesion when trying to systemize the subject will also be discussed. The last part of the review describes the buccal, nasal, ocular, vaginal and rectal routes and provides examples of what can be achieved in-vivo when using mucoadhesive formulations.

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“…Patients are known to tolerate gels better than other conventional dosage forms such as inserts or ointments. Some bioadhesive polymers have attracted considerable attention for their opportunity to prolong the contact of drug with a mucosal surface without inducing adverse local effects on the epithelium (37).…”

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confidence: 99%

Delivery of Granulocyte-Macrophage Colony-Stimulating Factor in Bioadhesive Hydrogel Stimulates Migration of Dendritic Cells in Models of Human Papillomavirus-Associated (Pre)Neoplastic Epithelial Lesions

Hubert¹,

Évrard²,

Maillard

et al. 2004

Antimicrob Agents Chemother

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Because of the central role of dendritic cells and/or Langerhans cells(DC/LC) in the induction of cellular immune responses, pharmacological agents that modulate the recruitment of these cells might have a clinicalinterest. The present study was designed to evaluate the capacity of several pharmaceutical formulations to topically deliver granulocyte-macrophage colony-stimulating factor (GM-CSF) on human papillomavirus (HPV)-associated genital (pre)neoplastic lesions. The formulations were evaluated for their bioactivity and for their potential to recruit DC in organotypic cultures of HPV-transformed keratinocytes. We found that a bioadhesive polycarbophil gel (Noveon) at pH 5.5 is able to maintain the bioactivity of GM-CSF at 4 or 37°C for at least 7 days, whereas a decreased activity of GM-CSF was observed when the molecule is included in other polymer gels. GM-CSF incorporated in the polycarbophil gel was also a potent factor in enhancing the colonization of DC into organotypic cultures of HPV-transformed keratinocytes since the infiltration of DC in the in vitro-formed (pre)neoplastic epithelium was very low under basal conditions and dramatically increased in the presence of GM-CSF gel. We next demonstrated that GM-CSF incorporated in polycarbophil gel induces the recruitment of human DC in a human (pre)neoplastic epithelium grafted into NOD/SCID mice. The efficacy of GM-CSF in this formulation was equivalent to that observed with liquid GM-CSF. These results suggest that GM-CSF incorporated in polycarbophil gel could play an important role in the recruitment of DC/LC in mucosal surfaces and be useful as a new immunotherapeutic approach for genital HPV-associated (pre)neoplastic lesions.

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Gamma-scintigraphy as a novel method to study the distribution and retention of a bioadhesive vaginal delivery system in sheep

Cited by 40 publications

References 10 publications

Mucoadhesive Microspheres for Controlled Drug Delivery

Mucoadhesive Microspheres for Controlled Drug Delivery

Pharmaceutical applications of mucoadhesion for the non-oral routes

Delivery of Granulocyte-Macrophage Colony-Stimulating Factor in Bioadhesive Hydrogel Stimulates Migration of Dendritic Cells in Models of Human Papillomavirus-Associated (Pre)Neoplastic Epithelial Lesions

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