PubMed · 13442002
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
A MASTURZO. 1957. [Epidural hydrocortisone of sciatica].. https://pubmed.ncbi.nlm.nih.gov/13442002/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
The process of hydrocortisone release from the nonionic polymer--methylcellulose hydrogels with the addition of 1% and 3% ethoxylated sorbitan alkanoate: polysorbate 20 or polysorbate 80, in the presence of 1,2-propylene glycol or PEG 200 has two stages. In the first stage the release rates are higher in comparison with the second stage. Concerning the hydrogel as a two-compartment system with micellas of polysorbates, the release rates of the first stage are in the range 4.27 x 10(-4)-6.23 x 10(-4) h-1 and in the second stage are in the range 8.29 x 10(-6)-1.16 x 10(-5) h-1 what can be affected by HLB of mentioned polysorbates.
A kinetic spectrophotometric method for the determination of hydrocortisone acetate based on its condensation with isonicotinic acid hydrazide is proposed. The method is applied to the determination of hydrocortisone acetate in a commercially available pharmaceutical preparation, presented as a pomade, that also contains another corticosteroid and additional active compounds. The operating procedure involves dissolving the pomade in chloroform and the addition of the reagent solution directly to the cuvette, in this way avoiding the previous extraction of analytes from the insoluble pomade matrix required by the alternative HPLC procedure. Calibration is performed by partial least-squares regression, using absorbance or first derivative spectra values recorded each minute during the first 30 min of reaction. Use of first derivative spectra overcomes possible scattered light problems produced by excipients precipitating, and produced slightly better results than absorbance data. The relative standard deviation obtained for 11 replicates analysed on different days was approx. 1.5%. The proposed method improves both accuracy and precision of the classical initial rate method and the precision of the HPLC procedure.
The raw material of hydrocortisone acetate was tested for the preparation of the "Hydrocortisone Acetate Reference Standard (Control 961)". Analytical data obtained were as follows: IR spectrum, specific absorption wave numbers at 3428, 1748, 1723, 1631, and 1375 cm-1; specific absorbance, E1cm1% (242 nm) = 406; thin-layer chromatography, no impurities were detected until 0.05 microgram; high-performance liquid chromatography (HPLC), 2-3 impurities were detected and the amount of the total impurities was estimated to be about 0.2%; assay by HPLC, 100.7%. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Reference Standard (Control 961).