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Thalidomide molecule, a synthetic derivative of glutamine, can undergo hydrolysis at physiologic pH to form glutamine. Additionally, l-glutamine is one of the starting materials in the synthesis of Thalidomide drug substance. The current USP method for testing glutamine is thin-layer chromatography (TLC) with ninhydrin spray visualization. A more quantitative and automated high performance liquid chromatography (HPLC) method utilizing indirect ultraviolet (UV) detection was developed and validated for the determination of the non-UV absorbing glutamine in Thalidomide drug substance and product. The HPLC mobile phases consisted of phosphoric acid, 2-naphthalenesulfonate sodium and methanol. 2-Naphthalenesulfonate was used as a UV detection probe for glutamine. A segmented isocratic elution program was used to elute glutamine and Thalidomide, respectively. The method was found to be specific for glutamine. The linearity was 0.05–1.25% glutamine with respect to a nominal concentration of 8 mg ml−1 Thalidomide sample. The limits of detection and quantitation were found to be 0.03 and 0.05% glutamine, respectively. The injection precision was 2.7% for area responses and 0.2% for the retention times. The recovery of glutamine at three concentration levels was found to be 100.8±2.8% from placebo and 99.2±5.8% from spiked Thalidomide drug substances. This newly developed HPLC method was used to determine glutamine in Thalidomide drug substances and products. The results from HPLC were in agreement with those from TLC. Therefore, the method developed is a suitable alternative to the current USP TLC procedure. Additionally, the method offers the advantage of being quantitative and automated. [Copyright &y& Elsevier]

Thalidomide, (1), has made a remarkable comeback from its days of a sedative with teratogenic properties due to its ability to selectively inhibit TNF-α, a key pro-inflammatory cytokine and its clinical benefit in the treatment of cancer. Thalidomide contains one chiral center and is known to be chirally unstable under in vitro and in vivo conditions. It has been hypothesized that different biological properties are associated with each isomer. Thus, chirally stable analogues of thalidomide, α-fluorothalidomide, (3) and α-fluoro-4-aminothalidomide (4) were prepared by electrophilic fluorination. Analogue 3 was found to be cytotoxic and did not inhibit TNF-α production in LPS stimulated hPBMC below toxic concentrations. On the other hand, 4 was non-cytotoxic at the tested concentrations and was found to be 830-fold more potent than thalidomide as TNF-α inhibitor. [Copyright &y& Elsevier]

Abstract: The thalidomide analogue and immunomodulatory drug (IMiD®) lenalidomide (CC-5013, REVLIMID™) is emerging as a useful treatment for a number of cancers and has recently entered phase III trials for multiple myeloma. It has been suggested that the anti-tumor effect of lenalidomide is related to its anti-angiogenic potency. In this regard, we have previously shown that lenalidomide inhibits angiogenesis in both rat and human in vitro models but does not affect endothelial cell proliferation. We now show that oral administration of lenalidomide attenuates growth factor-induced angiogenesis in vivo; the rat mesenteric window assay was utilized to show that lenalidomide significantly inhibits vascularization in a dose-dependent manner. We also found that lenalidomide significantly inhibits growth factor-induced endothelial cell migration. This correlates with the inhibitory effect of lenalidomide on growth factor-induced Akt phosphorylation, thereby providing a potential mechanism for its anti-migratory and subsequent anti-angiogenic effects. These data further support the use of lenalidomide as an orally administered drug for the effective treatment of angiogenesis-dependent conditions, including cancer, and suggest a potential mechanism of action. [Copyright &y& Elsevier]

Thalidomide is a racemic glutamic acid derivative approved in the US for erythema nodosum leprosum, a complication of leprosy. In addition, its use in various inflammatory and oncologic conditions is being investigated. Thalidomide interconverts between the (R)- and (S)-enantiomers in plasma, with protein binding of 55% and 65%, respectively. More than 90% of the absorbed drug is excreted in the urine and faeces within 48 hours. Thalidomide is minimally metabolised by the liver, but is spontaneously hydrolysed into numerous renally excreted products. After a single oral dose of thalidomide 200mg (as the US-approved capsule formulation) in healthy volunteers, absorption is slow and extensive, resulting in a peak concentration (Cmax) of 1–2 mg/L at 3–4 hours after administration, absorption lag time of 30 minutes, total exposure (AUC&infinit;) of 18 mg · h/L, apparent elimination half-life of 6 hours and apparent systemic clearance of 10 L/h. Thalidomide pharmacokinetics are best described by a one-compartment model with first-order absorption and elimination. Because of the low solubility of the drug in the gastrointestinal tract, thalidomide exhibits absorption rate-limited pharmacokinetics (the ‘flip-flop’ phenomenon), with its elimination rate being faster than its absorption rate. The apparent elimination half-life of 6 hours therefore represents absorption, not elimination. The `true' apparent volume of distribution was estimated to be 16L by use of the faster elimination-rate half-life. Multiple doses of thalidomide 200 mg/day over 21 days cause no change in the pharmacokinetics, with a steady-state Cmax (Cssmax) of 1.2 mg/L. Simulation of 400 and 800 mg/day also shows no accumulation, with Cssmax of 3.5 and 6.0 mg/ L, respectively. Multiple-dose studies in cancer patients show pharmacokinetics comparable with those in healthy populations at similar dosages. Thalidomide exhibits a dose-proportional increase in AUC at doses from 50 to 400mg. Because of the low solubility of thalidomide, Cmax is less than proportional to dose, and tmax is prolonged with increasing dose. Age, sex and smoking have no effect on the pharmacokinetics of thalidomide, and the effect of food is minimal. Thalidomide does not alter the pharmacokinetics of oral contraceptives, and is also unlikely to interact with warfarin and grapefruit juice. Since thalidomide is mainly hydrolysed and passively excreted, its pharmacokinetics are not expected to change in patients with impaired liver or kidney function. [ABSTRACT FROM AUTHOR]

Leprosy is a chronic infection of the skin and nerves caused by Mycobacterium leprae. Erythema nodosum leprosum (ENL) is a reactive state in lepromatous leprosy. Thalidomide has been used to treat ENL since the 1960s. One of its mechanisms of action is anti-inflammatory through selective inhibition of the pro-inflammatory cytokine TNF-α produced by monocytes. [Copyright &y& Elsevier]

Liquid chromatography–tandem mass spectrometric assays were developed for the sensitive, rapid and high throughput bioanalyses of thalidomide in human plasma and semen. The matrices were first stabilized with 0.025 M Sorensen’s citrate buffer at pH 1.5 to prevent spontaneous hydrolysis. Buffered thalidomide was stable when stored at room temperature for 24 h and for up to three freeze–thaw cycles. Samples were extracted using SPE cartridges. Extracts were then injected into the LC–MS–MS equipped with a reversed-phase column and an APCI interface in the negative ion mode. Calibration curves for both matrices were linear with r>0.99 from 2 to 250 ng/ml and ng/g. Inter-assay precision (RSD) of plasma and semen calibration standards were 2.6–11.6 and 1.9–12.4%, respectively. Recoveries from plasma and semen were greater than 69 and 78%, respectively. Batch sizes of 100 samples per matrix were analyzed with a total run time of 5 h. The methods successfully determined concentrations of thalidomide from a clinical study to levels as low as 7 ng/ml plasma and 8 ng/g semen, respectively. [Copyright &y& Elsevier]