Preservation of Solubilized and Emulsified Systems I: Correlation of Mathematically Predicted Preservative Availability with Antimicrobial Activity

Benefits of cetalkonium chloride cationic oil-in-water nanoemulsions for topical ophthalmic drug delivery

“…that only the free forms of the preservative (i.e. BAK derivatives) present in the aqueous phase of an o/w nanoemulsion were available for antibacterial activity, and therefore exerted ocular surface cell membrane toxicity . Thus, it is very important to have the lowest concentration of free/micelle BAK derivative molecules in the aqueous phase to avoid or limit as much as possible the side effects induced by these free molecules.…”

“…BAK derivatives) present in the aqueous phase of an o/w nanoemulsion were available for antibacterial activity, and therefore exerted ocular surface cell membrane toxicity. [42,43] Thus, it is very important to have the lowest concentration of free/micelle BAK derivative molecules in the aqueous phase to avoid or limit as much as possible the side effects induced by these free molecules. Hence, for a better ocular tolerance and safety profile of the cationic o/w nanoemulsion, the higher the lipophilicity of the cationic agent, the better.…”

Otimização de suspensões de benzoilmetronidazol

“…Já na fórmula de número 4 contendo Nipagin R (metilparabe e Tween 60 R (polissorbato 60), haveria maior probabilidade de ocorrer a interação en conservantesfenólicos e os tensoativosnão iônicos (7,8,49,86,113,120,142,145). Segun KALISH (81) os parabenos formam complexos com os tensoativos não iônicos, e isto po conduzir à diminuição ou mesmo a eliminação da concentração livre do conservan resultando em uma formulação com o seu sistema conservante comprometido.…”

“…Vários aut verificaram diminuicão da atividade antimicrobiana dos conservantes e, procura mostrar que ocorre a interação dessas substâcias com as macromoléculas, tanto tensoativo quanto do agente suspensor. (19,85,86,91,144) Compor uma fórmula medicamentosa requer estudo criterioso dos componentes. Aqueles que ainda hoje acreditam que formular é uma arte, escolhem adjuvantes por meio de conhecimentos adquiridos da literatura, por suas experiên pessoais e criatividade.…”

Effect of inoculum size on survival rate of Candida albicans and Aspergillus niger in topical preparations

“…The addition of preservatives to pharmaceutical preparations is often necessary to guarantee their microbiological quality during shelf-life and period of use. In the 1960s and 1970s the theoretical basis for the preservation of disperse systems was developed (Pisano and Kostenbauder 1959;Wedderburn 1964;Kazmi and Mitchell 1978). However, the mathematical formulae that were derived have little practical significance because of the complex composition of many of the products (Van Doorne 1992).…”