Table 2.9: Formulation consideration of different dosage forms of oral liquids

Sr. No. Dosage form Formulation aspects (purpose) Considerations (agents)

1. Solution Protecting the API Buffers, antioxidants, preservatives

Maintaining the appearance Colorings, stabilizers, antimicrobial

preservatives, co-solvents

Taste/smell masking Sweeteners, flavourings

Table 2.8: Parameters to be considered while scale-up with respect to the different dosage forms

Sr. No. Dosage form Parameters to be considered

1. Solution Tank size (diameter), impeller type, impeller diameter, the rotational

speed of the impeller, number of impellers, number of baffles, the

mixing capability of impeller, clearance between impeller blades and

wall of the mixing tank, height of the filled volume in the tank,

filteration equipment (should not remove active or adjuvant

ingredients), transfer system, passivation of SS (prereacting the SS

with acetic acid or nitric acid solution to remove the surface alkalinity

of the SS)

2. Emulsion Addition and dispersion of suspending agents (lab-scale—sprinkling

method and production-scale—vibrating feed system), hydration/

wetting of suspending agent, time and temperature required for

hydration of suspending agent, mixing speeds (high speed leads to

air entrapment), selection of the equipment according to batch size,

versator (to avoid air entrapment), mesh size (the one which is chosen

must be capable of removing the unwanted foreign particulates but

should not filter out any of the active ingredients. Such a sieve can

only be selected based on production batch size trials.)

3. Suspension Temperature, mixing equipment, homogenizing equipment, in process

or final product filters, screens, pumps and filling equipment, phase

volumes, phase viscosities, phase densities

20 Industrial Pharmacy II

2.4 PILOT-PLANT SCALE-UP CONSIDERATIONS FOR SEMISOLIDS

Semisolid dosage forms are composed of mainly two phases, i.e. oil and water. One of

the phases is a continuous or external phase and the other one is dispersed or internal

phase. The active pharmaceutical ingredient is mainly dissolved in one phase and if it

is insoluble in one or both phases, then a third phase is introduced. This is known as a

three-phase system.

Various factors affect the physical property of the semisolid dosage form. Some of

them are as follows:

i. Size of dispersed particle

ii. The interfacial tension between the phases

iii. The partition coefficient of an active ingredient in between the phases

iv. Rheology of product

v. The viscosity of both phases

vi. Nature of the third phase (if introduced)

These all factors mentioned above determined the release as well as other

characteristics of drugs. The following parameters of equipment used are to be

considered during pilot-plant scale-up of semisolids (Table 2.10).

The other considerations for processes (during the manufacturing of semisolid

dosage form) are:

i. Mixing speed

ii. Addition of active ingredients

iii. Product transfer

iv. Working temperature range

v. Shear during handling and transferring of product

vi. Working temperature range

vii. Component homogenization

Table 2.9: Formulation consideration of different dosage forms of oral liquids (Contd.)

Sr. No. Dosage form Formulation aspects (purpose) Considerations (agents)

2. Suspension Protecting the API Buffers, antioxidants, preservatives,