Sulfacetamide sodium

A 25% sulfacetamide sodium ointment is needed for certain topical antibiotic activity. In what proportion may 40%, 30%, and 10% sulfacetamide sodium ointments be mixed in order to prepare a mixture of 25% concentration ... 

Prednisolone acetate sulfacetamide sodium Blephamide Liquid petrolatum, polyethylene... 

Synonyms. Soluble Sulphacetamide Sulfacetamide Sodium Sulfacylum Natrium. 

Sulfa..., see also under Sulpha.. Sulfabenzamine, 716 Sulfabenzpyrazine, 980 Sulfabon, 983 Sulfacarbamide, 995 Sulfacetamide, 981 Sulfacetamide sodium, 981 Sulfachloqjyridazine, 982 Sulfactin, 550 Sulfacylum natrium, 981 Sulfadiazine, 982 Sulfadiazine sodium, 983 Sulfadimerazine, 984 Sulfadimethoxine, 983 Sulfadimezinum, 984 Sulfadimidine, 984 Sulfadimoxinum, 978 Sulfadoxine, 978 Sulfaduran, 983 Sulfaethidole, 985 Sulfafurazolum, 986... 

Sulfacetamide sodium (Albucid) in solutions stronger than 5% can cause burning and stinging when applied to the eyes, but this brief discomfort is usually tolerated without serious complaints. Sulfacetamide still compares favorably with newer antibiotics since it is effective against superficial ocular infections caused by a variety of microorganisms. However, serious allergic reactions can develop after ocular treatment (211). 

Sulfacetamide Sodium, USP. iV-Sulfanilylacctiiniide monosodium salt (Sodium Sulamyd) is obtained as the mon-ohydratc and is a white, txlorlcss, bitter, crystalline powder that is very soluble (I 2.. i) in water. Because the sodium salt is highly soluble at the physiological pH of 7.4. it is especially suited, as a solution, for repeated topical applications in the local management of ophthalmic infections sascepti-ble to sulfonamide therapy. 

Sulfacetamide sodium is the monohydrate of the sodium salt of sulfacetamide. It is highly soluble in water and is used for the preparation of eye-drops and eye ointments. 1.2 g of sulfacetamide sodium is approximately equivalent to 1 g of sulfacetamide (5). 

Sulfacetamide sodium pKai (amino group) 1.8 pKa2 (sulfonamide group) 5.4 (25°) (4,5). 

The ultraviolet spectra of sulfacetamide in 0.1 M hydrochloric acid and in 0.1 M sodium hydroxide solutions were recorded on a Shimadzu 240 UV-Visible spectrophotometer and are shown in Figure 1. The hypsochromic shift of the maximum at 270 nm to 256 nm in alkaline solution results from the ionisation of sulfonamide fraction (pKa 5.4) of the molecule. The UV spectral data for sulfacetamide and sulfacetamide sodium are reported in Table I. 

The infrared absorption spectrum of sulfacetamide sodium has been determined in KBr disc (4). The principal peaks appear at 825, 1090,1145,1264,1552,1600 cm 1. The infrared stretching frequencies of the amino group have been used to calculate the force constant, the band angle and the "S" character of the nitrogen orbitals of the N-H band (23,24). Infrared measurements of sulfonamides have been performed to study the imide-amide tautomerism (25) and to see if there is any change in the electronegativity of the SO2 group (26,27). Sulfacetamide in eye-drops and ointments has been identified by attenuated total reflectance (ATR) infrared spectra (28). 

A comparative in vitro study of the release of sulfacetamide sodium from eye ointments by dissolution and agar diffusion methods has been made and the effect of viscosity and particle size on the release examined. The aqueous based ointment gives a higher release of the drug than the greasy-based products. A linear relationship exists between agar diffusion release and the quantity of sulfacetamide released after sixty minutes as determined by the dissolution method (29). 

A 5% w/v solution of sulfacetamide sodium yields the reactions characteristic of sodium salts. 

The USP method (12) for the assay of sulfacetamide is based on nitrite titration followed by electrometric end-point determination using platinum electrodes. A 500 mg quantity of the drug is transferred to an open vessel. 20 ml of hydrochloric acid and 50 ml of water are added, the solution stirred until the content dissolved, cooled to about 15°, and slowly titrated with 0.1 M sodium nitrite. Each ml of 0.1 M sodium nitrite is equivalent to 21.42 mg of C8H10N2O3S. In the BP method (13), sulfacetamide sodium is assayed by amperometric titration. A 0.5 g quantity of the substance is dissolved in a mixture of 50 ml of water and 20 ml of 2 M hydrochloric acid and 3 g of potassium bromide are added. The solution is cooled in ice and sulfacetamide content determined amperometrically by titration with sodium nitrite. Each ml of 0.1 M sodium nitrite is equivalent to 0.02362 g of CsH9N2Na03S. 

Sulfacetamide, A benzoyl sulfanilamide and sulfathiazole have been determined in pharmaceutical preparations by measuring absorbance of the mixture in 0.1 N hydrochloric acid at 220,235 and 280 nm respectively (42). Madsen et al. (43,44) have performed computer analysis of the multicomponent UV spectra of sulfonamides. The errors in concentration determined from the spectra between 240 and 272 nm are lower when the spectra are analysed by a linear-squares method considering the data over the whole wavelength range compared with the determination using the data at a single wave length. The method has been applied to the assay of sulfacetamide sodium eye-drops. 

Sulfacetamide in ophthalmic solutions can be determined by its reaction with phenothiazine and N-bromosuccinimide at pH 6 to yield a blue product which absorbs at 605 nm. The recoveries are 96.7-100.7% (62). Sulfacetamide has been determined by its reaction with o-chloranil at pH 9 to yield a purple product with absorption maximum at 525 nm. Beer s law is obeyed over the concentration range 10 to 70 pg/ml of sulfacetamide sodium (63). 

Sulfacetamide sodium and other weak bases which do not show a distinct end point on titration in aqueous solution can be determined by use of the half-neutralization point. Three methods are employed for locating the midpoint from the potential (mV) versus volume added curve of a pH titration. The measured error is about 1% (66). 

Sulfacetamide and prednisolone acetate in a compound sulfacetamide ophthalmic ointment have been determined by HPLC. The peak of sulfacetamide sodium is well separated from those of the other constituents when using methyl cyanide-1 % acetic acid solution (15 85) as the mobile phase on /t-Corasil Cis column. The two compounds are determined by calculation of the peak area ratios using thiamine hydrochloride and methyl paraben as the internal standards. The maximum errors are 0.39% and 1.2% respectively (96). 

The oxidation of sulfacetamide sodium by peroxydisulfate ion to azobenzene derivatives follows second-order kinetics. The reaction is very sensitive to pH and the rate increases with increase in pH in the region 1.2-7.76. The rate decreases with decrease in dielectric constant of the medium, and a plot between log k2 and D 1 is linear. The reacion is inhibited by the presence of diphenylpicryl hydrazyl (102,103). 

Aqueous solutions of sulfacetamide sodium are affected by temperature. A freshly prepared solution in nitrogen filled ampoules, when sterilized by autoclaving at 115°C, produces no color whereas the air filled ampoules become appreciably darker (104). Sulfacetamide solutions autoclaved at 115°C have been shown to deposit the crystals of sulfanilamide (105). 

The pH is the most important factor in the stability of sulfacetamide sodium solutions. Among the 20% ophthalmic solutions of the drug, the greatest stability (to two years) is shown by the solutions with a pH of 8-8.5 (112). The addition of 200mg/100 ml of sulfacetamide to 30% ophthalmic solutions of sulfacetamide sodium decreases the pH from 9.3-9.6 to 7.3-8.4 and increases the shelf life of the solution after sterilization at 100°C for 30 minutes to more than one year (113). 

The effect of y- irradiation on sulfacetamide sodium in aqueous solutions and in the solid state has been studied. Pulse radiolysis and steady state experiments demonstrate that hydrated electrons (Saq) and hydroxyl radicals (OH.) are mainly responsible for the degradation between 1CT4 and 1.2 M solute concentrations. The reaction with eaq yields sulfanilic acid and an unidentified product (124). 

Discoloration of sulfacetamide by oxidation can be prevented by removal of oxygen from aqueous solutions and by sealing in colored ampoules. The 20-30% ophthalmic solutions of sulfacetamide sodium... 

Very high aqueous concentrations of sulfacetamide sodium (30%, pH 7.4) are nonirritating to the eye and are effective against susceptible microorganisms. The drug penetrates into ocular fluids and tissues in high concentrations (128). It is bound to plasma protein to the extent of 15 to 18% (4). The plasma half life is reported as 7 to 12.8 hours (129). 

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