Drugs online research references
Anal Biochem. 1989 Jun;179(2):288-90.
Spectrophotometric assay of hydroxylated by-products in penicillin V fermentations and its application in screening of mutant penicillin producer strains on agar media.
Palotas B, Szaszhegyessy V, Horvath M.
BIOGAL Pharmaceutical Works, Biotechnology Department, Pallagi, Hungary.
A fast and sensitive spectrophotometric method has been developed to measure the level of hydroxylated by-products (p-hydroxyphenoxyacetic acid and p-hydroxypenicillin V) in penicillin V fermentations. The method is based on a color reaction of the above-mentioned phenolic by-products with nitrous acid, yielding yellow nitroso derivatives. Both the nitroso derivative of p-hydroxyphenoxyacetic acid and that of p-hydroxypenicillin V have an absorption peak at 450 nm in alkaline solution with a molar absorption of 4.00 x 10(3) M-1cm-1 for both compounds. No fermentation medium components were found to interfere considerably with the assay. On the basis of the color reaction, an agar prescreen method has been developed for isolation of nonhydroxylating Penicillium chrysogenum strains in strain-improvement programs.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2505637&dopt=Abstract
Am J Hosp Pharm. 1979 Feb;36(2):205-8.
Stability of penicillin V potassium in unit dose oral syringes.
Grogan LJ, Jensen BK, Makoid MC, Baldwin JN.
The stability of reconstituted penicillin V potassium (PVK) when stored in 6-ml plastic oral syringes at various temperatures and protected from light was studied. One batch of PVK was reconstituted with distilled water according to manufacturer's directions (label claim: 125 mg/ml). Samples of 5 ml were stored in plastic oral syringes at 4 C, 25 C, 41 C, 60 C or 75 C and assayed spectrophotometrically and microbiogically at various times. From an initial concentration of 113% of label claim, PVK stored at 4 C (refrigerated) reached 90% of manufacturer's label claim in 11.5 days (95% confidence level). PVK stored at 25 C (room temperature) was unstable after storage for less than 37 hours. PVK degradation followed a first-order process. No significant difference was found between the spectrophotometric and microbiological assay (p less than 0.05). Manufacturer's stability data for storage of reconstituted PVK in the original bulk container should not be applied to PVK repackaged in plastic oral syringes. The pharmacy department developed guideliness designed to prevent the administration of subpotent PVK.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=105635&dopt=Abstract
J Assoc Off Anal Chem. 1989 Nov-Dec;72(6):883-4.
Liquid chromatographic determination of penicillin V potassium in tablets: collaborative study.
Mopper B.
Food and Drug Administration, New York Regional Laboratory, Brooklyn 11232-1593.
A liquid chromatographic method for the determination of penicillin V potassium in tablets was collaboratively studied by 7 laboratories. The method uses an octadecyl silane reverse-phase column, a mobile phase of acetonitrile-methanol-0.01 M potassium phosphate monobasic (21 + 4 + 75 v/v/v), photometric detection at 225 nm, and sulfadimethoxine as an internal standard. Each collaborator received 6 samples: powdered composites of 2 commercial tablet preparations and 1 synthetic tablet powder mixture, each with blind duplicates. The mean repeatability and reproducibility relative standard deviations for commercial samples were, respectively, 1.10 and 1.46% (250 mg dosage), and 0.84 and 2.82% (500 mg dosage). The average standard recovery from the synthetic formulation was 99.1%, with repeatability and reproducibility relative standard deviations of 1.30 and 3.66%, respectively. The method has been adopted official first action.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2512278&dopt=Abstract
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