Packaging of pharmaceutical semisolid products are packaged in either jars, tubes, or syringes whereas ophthalmic, nasal, vaginal, and rectal semisolid products are almost always packaged in tubes or syringes.
The so-called ointment jars are made of clear or opaque glass or plastic. Some are colored green, amber, or blue. Opaque jars, used for light-sensitive products, are porcelain white, dark green, or amber. Commercially available empty ointment jars vary in size from about 0.5 oz to 1 lb.
In commercial manufacture and packaging of topical products, the jars and tubes are first tested for compatibility and stability for the intended product. This includes stability testing of filled containers at room temperatures (e.g., 20°C) as well as under accelerated stability test- ing conditions (e.g., 40°C and 50°C).
Tubes used to package topical pharmaceutical products are gaining in popularity. They are light in weight, relatively inexpensive, convenient for use, and compatible with most formulative components, and they provide greater protection against external contamination and environmental conditions than jars.
Ointment tubes are made of aluminum or plastic. When the ointment is to be used for oph- thalmic, rectal, vaginal, aural, or nasal applica- tion, they are packaged with special applicator tips. Tubes of aluminum generally are coated with an epoxy resin, vinyl, or lacquer to elimi- nate any interactions between the contents and the tube. Plastic tubes are made of high- or low-density polyethylene (HDPE or LDPE) or a blend of each, polypropylene (PP), polyethylene terephthalate (PET), and various plastic, foil, and/or paper laminates, sometimes 10 layers thick.
Each type of plastic offers special features and advantages. For example, LDPE is soft and resilient, and it provides a good moisture bar- rier. HDPE provides a superior moisture barrier
but is less resilient. PP has a high level of heat resistance, and PET offers transparency and a high degree of product chemical compatibility. Laminates provide an excellent moisture barrier because of the foil content, high durability, and product compatibility. These qualities and flexibility make plastic and plastic laminate tubes preferable to metal tubes for packaging of pharmaceuticals.
The cylindrical bodies of plastic tubes are made by extrusion and then joined to the shoulder, neck, and tip piece, which is made by molding. Most multiple-dose tubes used for pharmaceuticals have conventional, continuous thread closures. Single-dose tubes may be prepared with a tearaway tip. Metered-dose, tam- per-evident, and child-resistant closures are available. Standard sizes of empty tubes have capacities of 1.5, 2, 3.5, 5, 15, 30, 45, 60, and 120 g. Ointments, creams, and gels are most frequently packaged in 5-, 15-, and 30-g tubes.
Ophthalmic ointments typically are packaged in small aluminum or collapsible plastic tubes holding 3.5 g (about 0.125 oz) of ointment, as shown in Figure below.
The tubes, which are sterilized before being aseptically filled, are fitted with narrow-gauge tips which permit extrusion and placement of narrow bands of ointment on the inner margin of the eyelid, the usual site of application.
Either syringes for injection or syringes for oral use have been successfully used. The advantages include the exclusion of air from the system, and accurate quantities can be applied using the syringe to measure the amount needed.
Filling Ointment Jars
Ointment jars are filled on a small scale in the pharmacy by carefully transferring the weighed amount of ointment into the jar with a spatula. The ointment is packed on the bottom and along the sides of the jar, avoiding entrapment of air. The jar size should allow the ointment to reach near the top of the jar but not so high as to touch the lid when closed. Through the adept use of the spatula, some pharmacists place a curl in the cen- ter of the surface of the ointment. Ointments prepared by fusion may be poured directly into the ointment jar to congeal in it. This must be done cautiously to prevent stratification of the components. In large-scale manufacture of ointments,pressure fillers force the specified amount of ointment into the jars.
Filling Ointment Tubes
Tubes are filled from the open back end of the tube, opposite from the cap end (Fig. 10.6). Ointments prepared by fusion may be poured while still soft but viscous directly into the tubes with caution to prevent stratification of the com- ponents. On a small scale, as in the extempora- neous filling of an ointment in the pharmacy, the tube may be filled manually (Fig. 10.7) or with a small-scale filling machine (Fig. 10.8). The filled tube is closed and sealed. As depicted in Figure 10.7, manual filling of an ointment tube requires a number of steps: (a) The prepared ointment, placed on waxed or parchment paper and rolled into a cylindrical shape, is inserted into the open end of the tube and pushed forward as far as allowed. (b) With a spatula pressing against the lower portion of the tube and making a crease below the ointment fill, the paper is slowly removed, leaving the ointment in the tube. (c) The bottom of the tube is flattened, folded, and sealed with a crimping tool or clip.
Tubes can also be filled using a “caulking- gun” system where the semisolid is filled into the chamber and the product is delivered into the tube. The tubes can then be heat-sealed using a heat-sealing crimper for a nice, professional appearance. Industrially, automatic filling, closing, crimping, and labeling machines are used for large-scale tube packaging of semisolid pharmaceuticals (Fig. below. Depending on the model, machines have the capacity to fill about 1,000 to 6,000 tubes per hour. Rotary machines have four stations for tube feeding, cleaning, filling, and closing. Plastic and laminate tubes are closed and sealed by heat and crimping. Metal tubes are sealed by folding and crimping with or without a vinyl, latex, or lacquer sealant.
Electronic mortars and pestles can be used to prepare an ointment,cream, orgelin the dispensing container. The ingredients are placed in the container and the cap, which has a stirring rod and blade assembly, put in place. The unit can be programmed for thorough mixing using different speeds and up and down rates until the product is uniform. The rod is removed and the cap replaced with a dispensing cap. For administration, the bot- tom of the ointment jar is moved up, forcing the product out of the orifice in the dispensing cap. The small orifice cap is replaced for a tight seal.
Filling Syringes
Syringes can be filled either by drawing the semisolid into the barrel using the plunger (it may be necessary to soften the preparation by gentle heating first), or by removing the plunger and filling through the back end of the syringe. The plunger can then be reinserted. (This can be accomplished by placing a straightened paper clip down the inside of the barrel and inserting the plunger. The paper clip allows the escape of air until the plunger contacts the ointment. The paper clip can then be removed and the seal formed by the plunger is reestablished.)
