Packaging of Ophthalmic Preparation: Ophthalmic solutions, lotions, and suspensions have been packed almost entirely in plastic bottles since the introduction of the droptainer plastic dispenser. A few products remain in glass dropper bottles because of special stability considerations.
1. Plastic Droptainer Bottles:
The convenience of usage by the patient.
Decreased contamination potential.
Lower weight and cost.
The dispensing tip can be designed to deliver only one drop or a stream of fluid for irrigation, depending on the pressure applied.
If used properly solution remaining in the bottle is only minimally exposed to air-born contaminants during administration and thus will maintain very low to non-existent microbial content.
The major disadvantage of plastic is opaqueness due to which it is difficult for inspecting clarity and precipitate formation or any other change in the solution.
The plastic bottle and dispensing tip is made up of low-density polyethylene resin, which provides flexibility and inertness but the major problem being the sterilization aspect i.e they cannot be autoclaved. The method of sterilization applicable is radiation sterilization (gamma-irradiation) or gaseous sterilization (ethylene oxide).
High-density polyethylene resins can be utilized to overcome the problem of autoclaving, but it has its own disadvantage i.e. it is less flexible. The statement that they can be autoclaved may refer only to lack of visible change, however, autoclaving may alter the physical properties of plastic and thereby affect the permeation, leaching, and sorption of the container. Volatile components may also be lost. Radiation sterilization may also affect the physical properties of the plastic.
Plastics used in containers for ophthalmics frequently contain residues from the polymerization processes, plasticizers, stabilizers, antioxidants, pigments, and lubricants. Factors such as plastic composition, processing, and cleaning operations, contacting media, inks, adhesives, absorption, adsorption and permeability of preservatives, and conditions of storage may also affect the suitability of plastic for specific use.
2. Glass Dropper Bottles:
These are used for products, which are extremely sensitive to oxygen or contain permeable components that are not sufficiently stable in plastic. The glass should be type-I for maximum compatibility with the sterilization process and product. The glass container is made sterile by dry heat or moist heat.
The use of colorants for caps attains special importance. The red color is used to denote mydriatic drugs such as atropine and green color for mitotic drug-like pilocarpine.
3. Metal Collapsible Tubes:
(a) Tin tubes:
Ointments are packed in small collapsible tin tubes usually holding 3.5 g.
Advantages: It is compatible with a wide range of drugs in petrolatum-based ointments.
- Lower cost.
(b) Aluminium tubes:
Advantage: Aluminium tubes are used because of their lower cost.
Disadvantage: Internal coating is essential to impart resistance.
4. Plastic Collapsible Tubes:
The plastic tubes made from flexible low-density polyethylene resins have been considered as an alternative material but they do not collapse and tend to suck back the ointment.
A tube can be designed by a selection of laminate materials and their arrangement and thickness to provide the necessary compatibility, stability, and barrier properties. Laminated tubes are usually heat-sealed. The crimp usually contains the lot code and expiration date.
The screw cap is made up of polyethylene or polypropylene. Polypropylene must be used for autoclave sterilization. Polyethylene must be used for gaseous sterilization.
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