The new BIPM 1-V reference standard based on an array of Josephson junctions

1989 ◽  
Vol 38 (6) ◽  
pp. 1030-1035 ◽  
Author(s):  
D. Reymann ◽  
T.J. Witt
Keyword(s):  
Josephson Junctions ◽  
Reference Standard

Low-Tcramp-type Josephson junctions for SQUIDS

2002 ◽  
Vol 12 (3) ◽  
pp. 133-136 ◽  
Author(s):  
M. Podt ◽  
B. G.A. Rolink ◽  
J. Flokstra ◽  
H. Regalia
Keyword(s):  
Josephson Junctions

Application of silicon substrates for high-Tc Josephson junctions and SQUIDs

1998 ◽  
Vol 08 (PR3) ◽  
pp. Pr3-297-Pr3-300 ◽  
Author(s):  
S. Linzen ◽  
Y. J. Tian ◽  
U. Hübner ◽  
F. Schmidl ◽  
J. Scherbel ◽  
...  
Keyword(s):  
Josephson Junctions ◽  
Silicon Substrates ◽  
High Tc

ANTI-OVULATORY ACTIVITY OF STEROIDS ADMINISTERED BY GAVAGE IN THE ADULT OESTRUS RABBIT

1963 ◽  
Vol 42 (2_Suppl) ◽  
pp. S17-S30
Author(s):  
Fred A. Kind ◽  
Ralph I. Dorfman
Keyword(s):  
Dose Response ◽  
Active Compound ◽  
Subcutaneous Injection ◽  
Response Curve ◽  
Parent Compound ◽  
Dose Response Curve ◽  
Relative Potency ◽  
Reference Standard ◽  
Highly Active ◽  
Dose Levels

ABSTRACT Thirty-seven steroids have been studied as orally effective inhibitors of ovulation in the mated oestrus rabbit. Norethisterone served as the reference standard and a dose response curve was established between the 0.31 and 1.25 mg dose levels. Nine highly active anti-ovulatory compounds are described listed in a decreasing order of potency with norethisterone having the arbitrary value of one: 6-chloro-Δ6-dehydro-17α-acetoxyprogesterone (35), 6α-methyl-Δ1-dehydro-17α-acetoxyprogesterone (≥ 10), 6-fluoro-Δ6-dehydro-17α-acetoxyprogesterone(9), 6-methyl-Δ6-dehydro-17α-acetoxyprogesterone (5), Δ6-dehydro-17α-acetoxyprogesterone (≥ 3), 6α-methyl-17α-acetoxyprogesterone (2.6), 6-chloro-Δ1,6-bisdehydro-17α-acetoxyprogesterone (≥ 2), 2-hydroxymethyl-17α-methyl-17β-hydroxyandrostan-3-one (≥ 2), and 6α-fluoro-16α-methyl-17α-acetoxyprogesterone (≥ 1.25). The anti-ovulatory activity of a compound was not related necessarily to the progestational activity of a compound nor to the anti-gonadotrophic activity as measured in parabiotic rats. 6-Chloro-Δ60dehydro-17-acetoxyprogesterone was as effective by gavage as previously shown by subcutaneous injection. 2-Hydroxymethyl-17α-methyl-17β-hydroxyandrostan-3-one was at least 2.5 times more active by gavage than by injection. While 17α-acetoxyprogesterone was a very weak anti-ovulatory steroid, modifications of the structure by addition of methyl or halogen at the 6α position with or without unsaturation greatly increased the activity. 6-Chloro-Δ6-dehydro-27α-acetoxyprogesterone was the most active compound in this series showing a relative potency of 3500 times that of the parent compound 17α-acetoxyprogesterone.

BIOASSAY CHARACTERISTICS OF INDIVIDUAL URINARY GONADOTROPHIN EXTRACTS

1963 ◽  
Vol 42 (2) ◽  
pp. 214-224
Author(s):  
Raymond C. Mellinger ◽  
Jalileh A. Mansour ◽  
Richmond W. Smith
Keyword(s):  
Reference Material ◽  
Young Women ◽  
Reference Standard ◽  
General Acceptance ◽  
Modifying Factors ◽  
Large Numbers ◽  
The World ◽  
Quantitative Bioassay ◽  
Different Parts ◽  
Age And Sex

ABSTRACT A reference standard is widely sought for use in the quantitative bioassay of pituitary gonadotrophin recovered from urine. The biologic similarity of pooled urinary extracts obtained from large numbers of subjects, utilizing groups of different age and sex, preparing and assaying the materials by varying techniques in different parts of the world, has lead to a general acceptance of such preparations as international gonadotrophin reference standards. In the present study, however, the extract of pooled urine from a small number of young women is shown to produce a significantly different bioassay response from that of the reference materials. Gonadotrophins of individual subjects likewise varied from the multiple subject standards in many instances. The cause of these differences is thought to be due to the modifying influence of non-hormonal substances extracted from urine with the gonadotrophin and not necessarily to variations in the gonadotrophins themselves. Such modifying factors might have similar effects in a comparative assay of pooled extracts contributed by many subjects, but produce significant variations when material from individual subjects is compared. It is concluded that the expression of potency of a gonadotrophic extract in terms of pooled reference material to which it is not essentially similar may diminish rather than enhance the validity of the assay.

Synthesis, Analytical Characterization and Spectroscopic Investigation of Chloramphenicol Impurity A for the Quality Control of Chloramphenicol and its Formulation as Per International Compendium

2020 ◽  
Vol 17 (5) ◽  
pp. 382-388
Author(s):  
Aparna Wadhwa ◽  
Faraat Ali ◽  
Sana Parveen ◽  
Robin Kumar ◽  
Gyanendra N. Singh
Keyword(s):  
Quality Control ◽  
Synthesis Method ◽  
Analytical Techniques ◽  
International Markets ◽  
Therapeutic Effects ◽  
Reference Standard ◽  
Working Standard ◽  
Prior Art ◽  
New Synthesis ◽  
Synthetic Procedure

Objective: The main aim of the present work is to synthesize chloramphenicol impurity A (CLRMIMP- A) in the purest form and its subsequent characterization by using a panel of sophisticated analytical techniques (LC-MS, DSC, TGA, NMR, FTIR, HPLC, and CHNS) to provide as a reference standard mentioned in most of the international compendiums, including IP, BP, USP, and EP. The present synthetic procedure has not been disclosed anywhere in the prior art. Methods: A simple, cheaper, and new synthesis method was described for the preparation of CLRM-IMP-A. It was synthesized and characterized by FTIR, DSC, TGA, NMR (1H and 13C), LC-MS, CHNS, and HPLC. Results: CLRM-IMP-A present in drugs and dosage form can alter the therapeutic effects and adverse reaction of a drug considerably, it is mandatory to have a precise method for the estimation of impurities to safeguard the public health. Under these circumstances, the presence of CLRM-IMP-A in chloramphenicol (CLRM) requires strict quality control to satisfy the specified regulatory limit. The synthetic impurity obtained was in the pure form to provide a certified reference standard or working standard to stakeholders with defined potency. Conclusion: The present research describes a novel technique for the synthesis of pharmacopoeial impurity, which can help in checking/controlling the quality of the CLRM in the international markets.

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