Preparation of the RDFs.
RDFs of CTZ with various grades of HPMC E LV were prepared using a solvent casting method (2). An aqueous solution of HPMC
was prepared in distilled water, and CTZ was added to the aqueous polymeric solution. This step was followed by the addition
of menthol, which had been dissolved in ethyl alcohol (95%), and plasticizers such as PEG 400 or glycerol. Sweeteners aspartame
and sucralose, citric acid, and flavor were also added. The solution was cast on a 9-cm diameter glass Petri dish and dried
at room temperature for 24 h. The film was carefully removed from the Petri dish, checked for imperfections, and cut to the
required size to deliver the equivalent dose (2 × 2 cm2 ) per strip. The samples were stored in a dessicator at 30–35% relative humidity until further analysis. Film samples with
air bubbles, cuts, or imperfections were excluded from the study. The formulation batches are described in Table I and Table
Table II : Selection of sweeteners for taste masking of rapidly dissolving films.
Mechanical properties of the RDFs.
The RDFs were evaluated for mechanical properties using a universal testing machine (model LR 100 K Lloyd Instruments, Ametek,
Leicester, England) with load cell 100 N. RDFs of size 10 × 2.5 cm2 and free of physical imperfections were held between two clamps held 5-cm apart. The 10 × 2.5 cm2 dimension was selected because it is the minimum size required for sample testing on the machine. The RDFs were pulled by
the clamp at a rate of 50 mm/min. Mechanical properties of the film were measured in triplicate for each batch. Tensile strength,
elastic modulus, and percent elongation were calculated for the RDFs as described below.
Tensile strength is the maximum stress applied to a point at which the film specimen breaks and can be computed from the applied
force at rupture as a mean of three measurements and the cross-sectional area of the fractured film as calculated using the
Elastic modulus is the ratio of applied stress and corresponding strain (force in N) in the region of approximately linear
proportion of elastic deformation on the load displacement profile and calculated using the equation:
Percentage elongation was calculated using the following equation:
Fourier transfer infrared spectroscopy.
The identification of CTZ in RDF was conducted with a fourier transfer infrared spectrophotometer (Jasco, FTIR model 6100,
In vitro disintegration studies.
Disintegration time provided an indication about the disintegration characteristics and dissolution characteristics of the
film. For this study, the film as per the dimensions (2 × 2 cm2 ) required for dose delivery was placed on a stainless steel wire mesh containing 10 mL of distilled water. The time required
for the film to break was noted as in vitro disintegration time (2, 10).