Purpose:
To formulate bioadhesive clotrimazole vaginal tablets
using natural polymers in order to provide long-term
therapeutic action at the site of infection.
Methods:
The tablets were prepared by direct compression using
bioadhesive polymer mixtures: hydroxypropyl
methylcellulose/sodium carboxymethylcellulose (HPMC/NaCMC)
and HPMC/Guar gum (GG) in different ratios. Differential
scanning calorimetry (DSC) and Fourier transform
infrared (FT-IR) spectroscopic evaluations were carried
out to assess compatibility between the drug and the
excipients. The tablets were subjected to various pre-
and post-compression evaluations, including in vitro
drug release, in vitro bioadhesive strength, swelling
and stability studies.
Results:
The results show that all the formulations satisfied
Indian Pharmacopoeial specifications for tablet
parameters. DSC and FT-IR data indicate there was no
interaction between the drug and the excipients. Drug
dissolution rate at pH 6.0 followed the rank order: HPMC)/NaCMC
> HPMC/GG. There was increase in swelling index with
time at 37 0C. The combination of HPMC with
NaCMC showed greater mucoadhesive strength and superior
controlled drug release to the formulations prepared
with GG polymer mixture. Furthermore, the release
properties of the former in pH 6.0 buffer, as well as
release mechanism (n values), were negligibly affected
by ageing.
Conclusion:
This study indicates the possible use of suitable
mixtures of natural and semi-synthetic cellulosic
polymers for the preparation of clotrimazole
mucoadhesive tablets for application as a vaginal
controlled delivery system.
Keywords:
Clotrimazole, Swelling, Cellulosic polymers, Guar gum,
Bioadhesion, Release properties.
