Packaging Of Suspensions

Packaging is defined as the collection of different components which surround the pharmaceutical product from the time of production until its use. Pharmacist must aware of wide range of packaging material that relates directly to the stability and acceptability of dosage forms. For example, to optimize shelf life industrial pharmacist must understand inter-relationship of material properties, while the retail pharmacist must not compromise with the storage of the dosage forms.

Pharmaceutical suspensions for oral use are generally packed in wide mouth container having adequate air space above the liquid to ensure proper mixing. Parenteral suspensions are packed in either glass ampoules or vials. Suspension should be stored in tight containers protected from freezing and excessive heat and light. Label : “Shake Before Use” to ensure uniform distribution of solid particles and thereby uniform and proper dosage should exist.

Ideal Requirements Of Packaging Material
  • It should be inert.
  • It should effectively preserve the product from light, air, moisture, mechanical damage and other contamination through shelf life.
  • It should be cheap.
  • It should effectively deliver the product without any difficulty.
  • Carry the correct information and identification of the product
  • Tamper evident/child resistance/Anti counterfeiting

Materials Used For Packaging
Generally glass and various grades of plastics are used in packaging of suspension.

Glass for Suspension

Generally soda lime and borosilicate glass are used in preparation of non sterile suspensions. Some times it is advisable to use amber colored glass (UV light can’t pass through) where light is the cause of degradation of the product. Amber characteristics can be developed in the glass by addition of various types of additives.

Type of glasses and additives giving amber colour
Type of glass Additive giving amber color
Soda limeFeO + sulfur (in presence of reducing agent)
Borosilicate  FeO+TiO 2

Disadvantages of Glass Materials for Suspension
  • fragile
  • very heavy compared to plastic, make it difficult for handling and transport
  • glass constituents get extracted in to the product

So for sterile dosage forms powder glass test as well as water attack test has to be carried out to ensure the amount of alkali material leached out in the product. Also typical test for extractable material is some time carried out

Typical characteristics of borosilicate glass
Assay of borosilicate glass Value
Initial pH6
Final pH8
pH change ± 0.24
SiO2  ppm21.0
Na ppm.01
K ppm0.74
Al ppm1.3
Ba ppm0.7

Plastic for Suspension

Many positive attributes of plastic material for sterile as well as non-sterile pharmaceutical suspensions. Plastic is non breakable, have light weight and flexible.
Materials used for plastic as packaging material is Polyethylene, PVC, polystyrene, polycarbonate etc.

Drug plastic consideration

There are mainly five factors which is to be considered during selection of plastic as a packaging material for suspension.
  • Permeation
  • Leaching
  • Sorption
  • Chemical reaction
  • Alteration of the physical properties of plastic.
E.g. Deformation of polyethylene containers is often caused by permeation of gas and vapours from the environment. Sometimes solvent effect is also found to be the factor for altering the physical properties of plastic viz., oils has softening effect on polyethylene and PVC.

Closure And Liners
With an exception of ampoules all containers required elastomeric closure.
Factors affecting in selecting closure:
  • Compatibility with product
  • Effect of processing should not affect the integrity of the closure
  • Seal integrity
  • It should be stable throughout the shelf life
  • Lot to lot variability has to be considered.
Factors affecting in selecting liner:
  • Chemical resistance
  • Appearance
  • Gas and vapor transmission.
  • Removal torque
  • Heat resistance
  • Shelf life
  • Economical factors