Determination of Methyldopa new.pdf

Determination of Methyldopa

1. Determination of
Methyldopa
Section 7

2. Methyldopawasdiscoveredin1960,Itison
theWorldHealthOrganization'sListofEssential
Medicines.Analpha-2adrenergicagonistthathas
bothcentralandperipheralnervoussystemeffects.
itsprimaryclinicaluseisasananti-hypertensive
agent.

3. Class:
This compound belongs to the class
of organic compounds known as
phenylpropanoid acids. These are
compounds with a structure
containing a benzene ring conjugated
to a propanoic acid.

4. Uses:
is a medication used forhigh blood
pressure.It is one of the preferred
treatments forhigh blood pressure in
pregnancy.

5. Drowsiness
Headache
Lack of energy
Dizziness.
Lightheadedness
Nausea or
vomiting
Weakness
Fainting.
Side Effects

6. (2S)-2-amino-3-(3,4-dihydroxyphenyl)-2-
methylpropanoic acid

8. 1-Tablet:
500mg , 250mg ,125mg
2-Tablet (film coated) :
500mg/1 , 250mg/1 , 125mg/1
3-injection solution :
50mg/1ml
TYPE OF
METHYLDOPA

9. Mechanism of action
Although the mechanism of action has yet to be conclusively demonstrated,
the resultant hypotensive effect is most likely due to the drug's action on the
CNS. Methyldopa is converted into the metabolite, alpha-
Methylnorepinephrine, in the CNS, where it stimulates the central inhibitory
alpha-adrenergic receptors, leading to a reduction in sympathetic tone, total
peripheral resistance, and blood pressure. Reduction in plasma renin activity,
as well as the inhibition of both central and peripheral norepinephrine and
Serotonin production may also contribute to the drug's antihypertensive
effect, although this is not a major mechanism of action. This is done
through the inhibition of the decarboxylation of dihydroxyphenylalanine
(dopa)—the precursor of norepinephrine—and of 5-hydroxytryptophan (5-
HTP)—the precursor of serotonin—in the CNS and in most peripheral
tissues.

10. Trade Name:

11. Physiochemical Properties:
1-Melting point (°C)
300 dec°C
2-Water Solubility
2.26 mg/mL
3-pKa(Strongest Acidic)
1.73
4-pKa(Strongest Basic)
9.85
5-Mwt: 211.084458
Formal charge : 0

13. Titration

14. Type of titration : non aqoustitration
Methyldopa:primary amine
Titrant:perchloric acid
Solvent :glacial acetic acid
Indicator : crystal violet
End point : violet to bluish green
Titration

15. Procedure
Take one tablet of
Methyldopa then
grind it
Transfer powder into
conical flask Add 30 ml of glacial
acetic acid
Add 0.1 ml of
acetous crystal
violet
Titrate with 0.1N
acetous per chloric
acid
1
2
3
4
5

16. F(Methyldopa) = Eq.WtMethyldopa×N(HClO4) 1000= gm methyldopa
Eq.wt of methyldopa =
??????.??????�
��.����????????????�????????????����.
(M.Wt of methyldopa = 211.084458g g/mol , n=1
F(Methyldopa) =
211.084458×(0.1)
1000
= 0.0211 gm methyldopa
Amount of methyldopa found =Ep ×f HClO4×Fmethyldopa×1000 number of tablet=
mg/tablet
Recovery = weight found weight claimed (250) ×100=%
Acceptable range ( 90 –110% )
Calculation

17. Made by:
ضوعم ءامسا309
رصان يجنا314
ديعس ةي

ا316
دمحم ةمسب317
دمحم ةبيبح321
ةراس دمحم327
ةليهس ءلاع330
ناضمر ناهرون343