This preparation, which is included in the Dutch drug formulary, is used both as a base solution for eye drops and as an antimicrobial agent.
Formula:
Borax 25 g
Benzalkonium chloride 100 mg
Disodium edetate 1 g
Sterile distilled water ad 1000 ml
Substances included in the formula:
Borax- Sodium tetraborate decahydrate- Natriumtetraborat (2) [Ph.Eur.]- Sodium borate (2) [INCI; NF]- Borax médicinale:
According to the European Pharmacopoeia (Ph. Eur. 6.5), borax is a white or almost white crystalline powder, or colorless crystals or crystalline masses. It effloresces. Soluble in water; freely soluble in boiling water; freely soluble in glycerol. The pH of its 4% aqueous solution ranges between 9.0 and 9.6. According to the British Pharmacopoeia (BP), Sodium Borate and Sodium Tetraborate are official synonyms of each other. According to USNF 27 (Sodium Borate), sodium borate occurs as odorless, transparent colorless crystals or a white crystalline powder. Its solutions are alkaline to phenolphthalein. It effloresces in warm, dry air. Soluble 1:16 in water, 1:1 in boiling water, and 1:1 in glycerol; insoluble in alcohol. It should be stored in airtight containers.
Sodium borate (borax) is used in combination with boric acid as a buffer and antimicrobial agent in eye drops. It is also included as an emulsifying agent in creams. Sodium borate has also been used in veterinary medicine for its antiseptic, detergent, and astringent activity on mucous membranes.
CAUTION! Neither boric acid nor borax is used for systemic effect (internally).
Benzalkonium chloride- Zephiran- Zephiran chloride- Benzalkonium chloride [BAN1999; BP; INCI; INN; NF]:
It occurs as a thick gel or gelatinous pieces with an aromatic odor, white or yellowish-white in color. It is hygroscopic and soapy to the touch. When heated, it melts to form a clear mass. BP specifies that it should not contain more than 10% water, while USNF specifies not more than 15%. Freely soluble in alcohol and ether; the solubility of its anhydrous form in ether is 1:100. Its aqueous solution is slightly alkaline and foams strongly when shaken. It is incompatible with soaps and other anionic surfactants, citrates, iodides, nitrates, permanganates, salicylates, silver salts, and tartrates. In addition to substances contained in certain commercial grades of rubber and plastic, it has been reported to be incompatible with aluminum, cotton dressings, fluorescein sodium, hydrogen peroxide, kaolin, hydrous wool fat, and certain sulfonamides.
Disodium edetate- Disodium EDTA- Edetate disodium [FP; USP]- Natriumedetat [ASK; Ph.Eur.]:
Disodium edetate is a white, odorless, crystalline powder. Soluble in water; slightly soluble in alcohol; practically insoluble in chloroform and ether. According to the British Pharmacopoeia (BP), the pH of its 5% aqueous solution is 4.0-5.5, and according to the United States Pharmacopeia (USP), it is between 4.0 and 6.0. According to USP, the pH of its injection solution is between 6.5 and 7.5 and contains varying amounts of disodium and trisodium edetate.
Edetic acid and edetates are used as chelating agents in pharmaceutical preparations, foods, and cosmetic products. They form water-soluble complexes called chelates with alkaline earth and heavy metal ions. When converted into complex form, these ions lose their properties in the free state. Edetic acid and edetates are mostly used as antioxidant synergists. Edetic acid and edetates also exhibit very weak antibacterial activity. However, due to their synergistic effects, they are used in combination with other antibacterial agents. Disodium edetate has been reported to enhance the activity of many antimicrobial preservatives, particularly benzalkonium chloride. They are generally used at a concentration of 0.01-0.1% as an antimicrobial preservative synergist. Edetic acid and disodium edetate are also used to reduce water hardness. They chelate with calcium and magnesium ions that cause water hardness. For the same reason, most cosmetic and skin care products contain edetic acid. Cosmetic soaps containing edetic acid are examples of such preparations.
Preparation of the formula:
Sterile distilled water is boiled, and borax is dissolved in it. After it reaches room temperature, EDTA and benzalkonium chloride are added, and the solution is made up to 1000 ml with sterile distilled water. Glass containers containing borosilicate may interact with alkaline solutions containing borax. As a result of this interaction, while causing the pH of the solution to increase, the glass in which the solution is to be stored also loses its required hydrolytic Class I property.
Aseptic working conditions must be observed during the preparation of the formula.
Specialist Pharmacist Ahmet Nezihi Pekcan
Pekcan Pharmacy – Konya
[email protected]
Tel: (332) 3520657
http://www.majistralformul.com/
Source:
- Formularium der Nederlandse Apothekers 2009
- RxMediaPharma®2016 Interactive Drug Information Source
