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Mauricio Sampaio ★ Brazil, 2013-09-02 17:50 (4285 d 02:53 ago) Posting: # 11409 Views: 9,064 |
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Dear, in Public Assessment Report of Lymecycline 408 capsules from MHRA (UK/H/1889/002/DC)* the pharmacokinetics results of bioequivalence study of Lymecycline is based on data from Tetracycline and not Lymecycline (page 13). However, in page 10, the Lymecycline is described as active substance. In this case Lymecycline is a prodrug and serves as a type of precursor to the intended drug (Tetracycline)? Please, clarify my doubt. * http://www.mhra.gov.uk/home/groups/par/documents/websiteresources/con205367.pdf |
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Dr_Dan ★★ Germany, 2013-09-02 22:53 (4284 d 21:50 ago) @ Mauricio Sampaio Posting: # 11411 Views: 7,460 |
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Dear Mauricio, The active ingredient lymecycline is a tetracycline antibiotic which is more readily absorbed from the gastro-intestinal tract than tetracycline, with a peak serum concentration of approximately 2mg/L after 3 hours following a 300 mg dose. It is a half synthetic combination of water soluble tetracyclin, the amino acid lysin and formaldehyd. After oral application this combination is hydrolised within the GI tract to tetracyclin, lysin and formaldehyd and therefore not available as lymecycline in the systemic circulation. In other words lymecycline is a pro-drug of tetracycline. Kind regards Dan — Kind regards and have a nice day Dr_Dan |
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Mauricio Sampaio ★ Brazil, 2013-09-03 21:58 (4283 d 22:45 ago) @ Dr_Dan Posting: # 11420 Views: 7,238 |
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Dear Dan, I am glad to hearing you again! Thank you for all support in this case. Your help were very important! We almost made a mistake in development of analytical method. Best regards |
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manojskr ☆ India, 2013-09-04 17:06 (4283 d 03:36 ago) @ Dr_Dan Posting: # 11436 Views: 7,619 |
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Dear Dr. Dan, We are also having same concern and had gone through many authentic literatures and papers but could not draw a conclusion that whether we should analyze Lymecycline or Tetracycline. Lymecycline level in plasma, if analyzable, will be our priority. Some of the papers state that Lymecycline is more readily absorbed from the gastro-intestinal tract than tetracycline with a peak serum concentration of approximately 2mg/l after 3 hours following a 300mg dose. After oral dosing it is absorbed readily with or without the presence of food and is excreted slowly in urine. The drug is lipid soluble. The serum half-life of lymecycline is approximately 10 hours. Another report, Public Assessment Report Lymecycline 408mg capsule,states "a washout period of 7 days is sufficient time for Lymecycline to be eliminated from body. A validated LC-MS/MS analytical methodology was used for quantification of Lymecycline from the human plasma samples. Hence, we need a confirmation that Lymecycline is actualy breaking into Tetracycline in GI tract and is not present in blood for detection at any measurable concentration level. Kind Regards, Manoj Singh |
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Dr_Dan ★★ Germany, 2013-09-04 22:05 (4282 d 22:38 ago) @ manojskr Posting: # 11439 Views: 7,242 |
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Dear Manoj Singh As Mauricio pointed out above the Public Assessment Report from MHRA (UK/H/1889/002/DC) states that the pharmacokinetics were based on Tetracycline and not Lymecycline as a consequence that Lymecycline is a prodrug which is not available in the systemic circulation. Kind regards Dan — Kind regards and have a nice day Dr_Dan |
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manojskr ☆ India, 2013-09-05 07:54 (4282 d 12:49 ago) @ Dr_Dan Posting: # 11441 Views: 7,226 |
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Dear Dr. Dan, Thanks a lot. Regards, Manoj Singh |
Ing. Helmut Schütz