Saline nasal sprays are readily available over-the-counter at most local pharmacies and offer users relief from irritated nasal passages. The nasal spray industry is a multi-million dollar industry, with saline sprays accounting for a signification portion of sales. Basic saline nasal sprays consist of water and sodium chloride. However, most commercial saline sprays also incorporate additives such as disodium phosphate and benzalkonium chloride to stabilise and preserve the product.
Saline sprays are most commonly found in two forms: isotonic and hypertonic. The concentration of sodium chloride in the product determines its designation. Isotonic saline sprays contain chloride in concentrations similar to our own bodies (~0.9%). The use of isotonic nasal sprays is generally a non-irritating way to flush out debris and introduce moisture into nasal passages. Hypertonic nasal sprays contain chloride concentrations higher than that of our own bodies (~3%). Hypertonic saline sprays are typically used as decongestants. Unlike isotonic sprays, hypertonic sprays draw moisture out of nasal passages and alleviate congestion.
The chloride concentration in each product type must be precise to ensure accurate labelling and to maintain consistency between products. The United States and European Pharmacopeias (USP and EP) recommend titration as an effective way to determine the chloride content of both types of nasal spray. In a chloride titration, silver nitrate is added to precipitate the chloride in the sample. Once all of the chloride is precipitated, the depletion of chloride or excess of silver can be detected with a chemical or potentiometric indicator.
A pharmaceutical manufacturer contacted Hanna Instruments interested in testing the chloride concentration of various saline spray products. Their products contain a separate sodium chloride packet that the user mixes with a solution prior to use. The manufacturer wanted to ensure that the premeasured sodium chloride packet contained the correct amount of salt to meet the specified concentration of their isotonic and hypertonic nasal sprays. They already had a full-scale laboratory and wanted a traceable, accurate solution for testing their products. Hanna Instruments suggested the HI902 Automatic Potentiometric Titrator with the HI4115 Silver/Sulphide electrode.
The customer appreciated having a high level of control over the method parameters and the ability to enable administrative options. Because the customer had to report their test data to the FDA, they had strict requirements for their data collection. The administrative options on the HI902 allow an administrator to lock the titrator with a password. When a titrator is locked, users cannot delete or alter any method parameters or reports. This prevents tampering with the analysis or associated data. Overall, the customer was happy with the accuracy and flexibility of the HI902 which allowed them to continue manufacturing high-quality products for millions of clients worldwide.