Table III indicates that the subsequent addition of citric acid and passion fruit flavor (batches T1 and T3) resulted in completely
taste-masked films. The in vitro disintegration time was 50 s and the in vivo disintegration time of batch T3 was 20 s. The addition of lemon flavor (batches T2 and T4) resulted in highly acidic taste
of the film, which was unacceptable. Batch T3 showed good elasticity and taste masking properties. Figure 1 indicates the
comparative in vitro dissolution profile of batch T3 in different dissolution media. Figure 1 shows that in 2 min batch T3 showed 100% drug release
in distilled water, 95% in 0.1 N HCl, and 80% in simulated saliva.
Figure 1: Comparative in-vitro dissolution profile of batch T3. (FIGURE IS COURTESY OF THE AUTHORS.)
Study of mechanical properties.
A suitable RDF requires moderate tensile strength, good percentage elongation, and low elastic modulus. Table IV shows the
comparative mechanical properties of various formulations prepared during the study. RDFs containing 2% and 4% HPMC E3 LV
without drug (i.e., batches 2E and 4E) showed extremely high tensile strength, poor percent elongation, and very high elastic
modulus. The same formulation in the presence of drug and plasticizer (i.e., batch E9) demonstrated lower tensile strength
compared with batch 2E and 4E. The percent elongation values increased and elastic modulus values decreased. The taste-masked
batches S4 and T3 had acceptable mechanical properties. The tensile strength was in a moderate range (4–9 N/m2 ). The percent elongation (21–28) and elastic modulus (35–165) were also satisfactory. These changes in the mechanical properties
can be attributed to the presence of plasticizer in batches E9, S4, and T3. Batch T3 showed the most acceptable mechanical
properties along with complete taste masking, which might be attributed to the presence of suitable plasticizers and flavors.
The stability study of the optimized batch T3 was carried out at 25 ?C for a one-year period. The batch was found be acceptable
visually, mechanically, with a slight increase in the in vitro and in vivo disintegration time of 55 s and 22 s, respectively.
Table IV : Comparative mechanical properties.
RDFs containing taste-masked CTZ showed acceptable properties such as tensile strength, elasticity, percentage elongation,
in vitro disintegration, and in vitro dissolution characteristics. The RDFs were transparent, without any air entrapment. The drug-release profiles indicated that
it could be used for the oral delivery of CTZ in chronic and acute urticaria as well as perennial rhinitis. Taste masking
could be achieved using suitable sweeteners, flavors, and sour ingredients. The various grades of HPMC E LV highly affected
the in vitro disintegration time and in vitro dissolution profiles. HPMC E3 LV was the most suitable grade for the manufacture of RDF containing CTZ.
Renuka Mishra is a lecturer in the department of pharmaceutical technology, and Avani Amin, PhD,* is principal and I/C director, both at the Institute of Pharmacy, Nirma University of Science and Technology, Sarkhej-Gandhinagar
Highway, Ahmedabad, Gujarat, India, tel. 91 02717 241900 to 04, fax 91 02717 241916, firstname.lastname@example.org
*To whom all correspondence should be addressed.
Submitted: May 1, 2008. Accepted: May 9, 2008.
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