Softgels (Soft Gelatin Capsules; Drug C)

This dosage form consists of a solution of active ingredient encased within a
spherical, plasticized gelatin shell. Unlike hard gelatin capsules, for which several
discrete operations are required to produce the final product, the softgel is
formed, filled, and hermetically sealed in one continuous operation [16]. Molten
gelatin mass is formed into two sheets or ribbons, each of which passes over a
die of the desired size and shape. At the point at which the two rotating dies
meet, the hemispheres are sealed and simultaneously filled with the solution of
active ingredient. Next the capsules are cleaned by immersion in an organic
solvent, dried, and inspected. (See Fig. 9.)
According to the process instructions, the active ingredient powder is dissolved
in vegetable oil with the aid of a solubilizer. Blend time is stated as 25
to 30 min. This is an elapsed time. Because a range of time is permitted, this
step is one for which historical data will be sought (Table 5). The bulk solution
is assayed to confirm that the prescribed weight of drug C was charged and
dissolution is complete before capsule filling may proceed. Concentration of the
active ingredient should vary very little from one batch to another with such a
straightforward process. We will want to confirm that this is the case. The purity
of each active ingredient raw material receipt is also of interest for reasons
previously stated.
The instructions for gelatin mass preparation direct that gelatin powder be
blended with water, a plasticizer, and colorant until a uniform consistency is
achieved, then heated until molten. The recommended blend time is 20 min at
a temperature of 60°C ± 5°. The temperature of the molten gelatin just prior to
formation into a ribbon is critical; too high a temperature causes the gelatin to
deteriorate, and a low temperature affects flow rate. Both conditions are to be
avoided for their deleterious effect on capsule formation. For these reasons,gelatin mass temperature is listed in Table 5. Blend time is of interest, too, as a
measure of process and raw material performance.
An important specification for gelatin is bloom strength, a quality of the
raw material that determines whether or not a capsule can be formed and sealed.
As with active ingredient purity, we will want to know this value for each lot
of gelatin used in the validation study.
The rationale of their selection is as follows: die rotation speed controls dwell time. If there is insufficient contact
time, the capsule halves will not properly seal. Subpotent softgels may result
from loss of liquid fill through a poorly developed seam. Gelatin ribbon thickness
determines capsule wall and seam thickness. Insufficient thickness will
contribute to poorly formed capsules and leakers. An overly thick ribbon results
in shell sealing problems. Ribbon condition is influenced by the temperature of
the gelatin mass, as previously noted. Relative humidity in the encapsulation
room is important to efficient drying. Minimally, we will want to know the
room condition during the time in which the 20 batches in this study were manufactured.
It would be best to examine environmental conditions over a longer
time period, say 1 year, to capture seasonal trends should they exist.
The batch record instructs the encapsulation machine operator to measure
and record seam and wall thickness every 45 min. Softgel weight is also checked
periodically by this operator. This information could be useful in demonstrating
process control but to a large extent seam and wall thickness are controlled by
manufacturing conditions for which historical data are already being sought. For
this reason, the results of these in-process monitors need not be pursued initially.
Consistent with the approach taken for other dosage forms previously discussed,
finished softgel weight data can be obtained from quality control reports when
dissolution and assay results are collected.