The aim of present study is to investigate the effect of flow
aids on the observed in vitro mucoadhesion of two representative
polymers;
polyoxyethylene and
Carbopol((R)) 971P. More recently it has been shown that the addition of small amounts of certain
excipients to a mucoadhesive formulation can lead to a substantial decrease in observed mucoadhesion in an in vitro test system, which suggests that formulation of these systems could be crucial in developing successful
dosage forms. A series of experiments has been carried out which indicates that the presence of flow
aids at high concentrations present in
tablets can affect the observed ex-vivo mucoadhesive bond.
Magnesium stearate (5%) exerts its negative effect on the mucoadhesion of
Carbopol((R)) 971P and
polyoxyethylene combination by hindering the hydration of the
polymer. Adhesion time of formulation containing 5%
magnesium stearate was found 4.7+/-0.34 h and percent hydration of same formulation was 70.12%.
Talc and colloidal
silicon dioxide (
Aerosil), which do not possess the same hydrophobic properties or have available
divalent cations were found to be viable alternatives to
magnesium stearate.