Dispensing efficiency of nonmetered topical spray aerosols
✍ Scribed by Peter Kabasakalian
- Publisher
- John Wiley and Sons
- Year
- 1969
- Tongue
- English
- Weight
- 314 KB
- Volume
- 58
- Category
- Article
- ISSN
- 0022-3549
No coin nor oath required. For personal study only.
✦ Synopsis
level. An indication that such a phenomenon occurs has been suggested in this paper when nonsparged vials assayed 16 rather than 21 %oxygen. To demonstrate this further, vials of another parenteral product were filled using both the conventional nitrogen-layering technique and also with no attempt to incorporate nitrogen into the vial. The oxygen content of the head space was determined at various time intervals after filling. Because this product was able to react with oxygen, Fig. 4 shows that measurements performed as little as 1-2 hr. after filling gave erroneous results. At the end of 5-6 hours, the data obtained implied that the product was adequately protected. The true oxygen level in the head space was determined by extrapolation to zero time (time of filling). These results further emphasize the need for an awareness of the elapsed time when determining the efficiency of a nitrogen-protecting system.
Antioxidant and Nitrogen-Although an antioxidant could not be considered for inclusion in the system discussed, it may be felt by some that an antioxidant can take the place of an inert atmosphere in other systems. The authors believe that the inert atmosphere should serve to protect a product during its manufacture, filling, and storage prior to use. In this way the integrity of the antioxidant is maintained for the actual use-life of the product. An antioxidant consumed during the filling and manufacture operations may not be available for protection during a product's use-life, unless large amounts are employed. High concentrations of antioxidants should not be used to overcome less than adequate manufacturing techniques, and the maximum amount permitted might not be sufficient to protect the product during both its manufacture and use-life. Al- though this study has been concerned with a parenteral product, the same approach to filling other dosage forms is obvious. Therefore, in an oral liquid product, where taste is important, it is desirable to use minimum rather than maximum antioxidant concentrations.
Conclusions-As a result of this study, it is felt that anyone using a conventional method for layering nitrogen onto an oxygen-sensitive product should closely scrutinize the technique. A procedure similar to that described in this paper would be useful with any oxygen-sensitive product. Although these studies indicated good nitrogen protection in vials layered by this method, it must be remembered that it represented only a single product in a particular size vial. Therefore, the specific conditions for producing minimum oxygen concentration must be evaluated for each individual product and container.
REFERENCES
(1) S . A. Schou, Am. . I .