Question { 14594 }

which solvent is highest poler
acetonitrile
dimethyl formamide
methanole
tetrahydrofurane
buffer solution

Answer

N,N-dimethyl formamide

Question { Cipla, 22439 }

why we wre doing linearity siudiec in hplc method validation

Answer

If the method is linear or not from certain range suppose
in assay validation the range is 50% to 150% we are
injecting minimum 6 levels and also Calculate the regration
line the correlation coefficient should be less than 0.999
Here regration line equation is y=mx+c

where y = Regration line
m = Slope
c = Intercept.

and also calculate residual sum of squares from theorical
and practical

Question { Reddy Labs, 191419 }

Why we use caffeine for HPLC calibration in Detector wave
ength accuracy test

Answer

caffeiene having different wavelents it having 2 maximas
and 1 minima.
1st maxima is 205nm
2nd maxima is 273nm
minima is 245nm
and it is primary reference standard and also suggested in
pharmacopiea.

Question { Alkem Labs, 36510 }

what is principal of karl ficher instrument!

Answer

How much amount of water content present in substance by
utilising Water, Iodine and sulphur dioxide inpresence of
lower alcohol methanol and inpresences of base such as
pyridine.

Question { Cipla, 23644 }

Why 10%,20%,30% Sucrose solution is used for the calibration
of polarimeter?

Answer

for linearity purpose and calculation of correlation
coefficient

Question { Jubilant Organosys, 36990 }

What is the difference b/w OVI Solvents and Residual
Solvents in case of Gas Chromatogaphy and What is its
Detection Limit?

Answer

Residual Solvents in pharmaceuticals are Organic volatile
chemicals that are used or produced in the manufacture of
drug substance or excipient or in the preparation of drug
product.
Residual solvents refer to the amount not removed during
the purification of the drug product.

Organic Volatile Impurities <467>
1.Proposed in PF 14(2) (1988)
2.Incorporated into 3rdSupplement to USP 22(1990)
3.Acceptance criteria based on relative toxicity.
now the new name is Residual solvents <467>

Organic Volatile impurities are
1.Dichloromethane(600ppm)
2.Chloroform(60ppm)
3.Trichloroethylene(80ppm)
4.1,4-Dioxane(380ppm)
these four solvents are OVI solvents
Remaining solvents are residual solvents.
These are classified into 4 classes
Class 1 Solvents are 5
Class 1 Solvents are 27
Class 1 Solvents are 27

but class 4 solvents not having toxicological data.
there are 5 Solvents
detection limit is very low.