BKC applications

Nasal formulations

Multidose sterile pharmaceutical products are prone to contamination, both from environmental and corporeal flora. Microbial contamination can present a threat to the safety, the purity or the efficacy of nasal products such as nasal sprays and nasal drops, hence the importance of utilizing an effective preservative.

For formulations coming into contact with mucosal tissue, it is necessary to preserve against contamination by utilizing only the purest and safest ingredients. In both human and veterinary nasal formulations, one of the most common and effective preservatives is Benzalkonium Chloride (BKC/BAK). Our FeF Benzalkonium Chloride is widely used as an excipient in nasal sprays, nasal drops, and ointments, where its concentration typically varies from 0.005% up to 0.2%.


The different alkyl (fatty) chain lengths give Quats (e.g., Benzalkonium Chloride) different properties. For example, antimicrobial activity is greater for shorter chain lengths; however, skin sensitivity decreases as the chain length increases. Shorter chain lengths are more soluble, and they also foam more.

Our production and process know-how allows us to offer Benzalkonium Chloride with a completely well-defined alkyl chain length distribution, whether it is with our standard chain length or with customized chain length distributions. Our standard chain length distribution in Benzalkonium Chloride is approx. 65% C12 and 35% C14, with max. 5% of C16. We also offer other chain length distribution products or develop your own customized product.


Product characteristics

Solubility: FeF Benzalkonium Chloride is miscible with water or lower alcohols, such as methanol, ethanol, and propanol in all ratios. It is not miscible with benzene or ether. Indicative solubility of Benzalkonium Chloride in %w/w at 20°C in water:

Solubility decreases as the alkyl chain length increases.

Compatibility: Mixing BKC with ordinary soaps and/or with anionic detergents may decrease the activity.

As Quats (e.g., Benzalkonium Chloride) are cationic compounds, they should not be mixed with anionic compounds which would have a neutralizing effect. Quats can be inhibited by Tween™ and by lecithin. Avoid mixing Benzalkonium Chloride (BKC) with citrates, iodides, nitrates, perman-ganates, salicylates, silver salts, and tartrates. Incompatibilities have also been reported with other substances including aluminium, fluorescin sodium, hydrogen peroxide, kaolin, and some sulfonamides.

Stability: 5 years shelf life.

Other: Colourless and odourless in finished product formulation, easy to formulate, surface active/adhesive, non-volatile, and very stable. Suited for a variaty of nasal applications such as nasal sprays and nasal drops.

Antimicrobial effect

FeF Quats are effective at all pH levels. However their effectiveness increases when the pH increases. The higher the pH, the lower the concentration needed to obtain an antimicrobial effect.

Benzalkonium Chloride (BKC) has been tested against several relevant microbial strains and shown to be effective against a wide range of microorganisms at low concentrations. FeF Benzalkonium Chloride (BKC) is compared here with ethanol and a positive control containing Meropenem (a broad-spectrum antibiotic).

Table 1: Minimal Inhibitory Concentrations. Mean results in % or μg/ml.

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