E-drug: Norgestrel and combined contraceptive pills (cont'd)
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Dear Marcel,
1. There must be a misunderstanding. To my knowledge,
LEVOnorgestrel, and not the DEXTRO, is the active substance. The most
recent reference I have to support this is NOVAK'S Gynaecology, 12th
edition, 1997, page 242: "norgestrel exists as two stereoisomers,
identified as dextronorgestrel and levonorgestrel. Only levonorgestrel
is biologically active".
2. The classical pill ("normodosed" and "minidosed") contains in almost
all cases, l-norgestrel. The essential drugs list for MCH (see for
example "Mother and Baby Package", WHO/FHE/MSM 94.11), includes the
biphasic pill ethynilestradiol + levonorgestrel, and the
progestin-only-pill levonorgestrel. Other examples (French
Pharmacopeia): MINIDRIL (LNG 0.15mg+EE0.03mg per pill, blister of 21
pills), produced by Wyeth.; ADEPAL - a biphasic pill produced by
Wyeth: 7 pills LNG 0.15mg+EE0.03 mg and 14 pills LNG 0.2 mg+ EE 0.04
mg). And also TRINORDIOL (Wyeth) triphasic pill EE+LNG. These pills
are, I think, the cheapest - for example, ADEPAL costs about 10-15 FF
a month. I do not know a pill containing dextronorgestrel. I know pills
containing the racemic mixture - e.g. STEDIRIL (DLNG0.5mg + EE 0.05
mg).
POP contain also LNG ex: MICROVAL (not very expensive - about 10 -
15 FF).
In Romania, for example, the World Bank advised a few years ago for
its FP program the classical combination LNG+EE, and bought in
Hungary for about 0.40 USD /blister.
3. Concerning your question about "racemic mixture". In fact, the two
stereoisomers differ through their optical characteristics, to deviate
the polarised light to the right (dextroisomer; in Latin dextro=right) or
to the left (levo=left). A mixture of equal quantities of two is optically
inactive. This is called the "racemic".
I hope my answer can help you.
Best wishes,
Dr Denisa Elena IONETE
Ob-Gyn, MSc in Public Health / Epidemiology
Consultant, Reproductive Health
Libreville, Gabon
ccdi@compuserve.com
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