RO-ICAC'2014 Analytical Chemistry for a Better Life September 17 th - PowerPoint PPT Presentation

2nd International Conference on Analytical Chemistry RO-ICAC'2014 Analytical Chemistry for a Better Life September 17 th -21 st 2014 Târgovi ș te, Romania Andrei Medvedovici Department of Analytical Chemistry, Faculty of Chemistry, University of Bucharest, # 90-92 Panduri Ave., Bucharest-050663, Romania, E-mail: avmedved@yahoo.com

Hydrophobicity: the physical property of a molecule that is seemengly repelled from a mass of water. Lipophilicity (as an extension of the hydrophobic character): includes favorable interactions that contribute to the distribution of a chemical entity between water and other solubilizing media, representing a manifestation of the characteristics of the system in which the solute is placed. log K o/w or simply, log P: a measure of the lipophilic character. S.K. Poole, S.F. Poole, J. Chromatogr. B, 797 (2003) 3-19.

n-Octanol A O 1. If [A] o or [A] W are  , very sensitive A W methods are necessary for assaying A. Water 2. Mutual relative solubility of the two   media ( n -octanol in water and water in A  O K n -octanol, respectively). i.e. - solubility   / O W of n -octanol in water at 25 o C is 0.56 A W g/L.

  A V       S . Ph . M . Ph . K k k   A A V M.Ph. . M Ph S . Ph . A W if k w is the retention factor for a hypothetical M.Ph. composition containing 0% Organic Modifier: C8 bulk assimilated to n -octanol layer A O    A S.Ph. K k ; O / W W           A A log K log P log k Log O / W W SiR 2 SiR 2 SiR 2 SiR 2 SiR 2 O O O O O O Si O Si O Si O Si O Si O O O O O O

4.5 y = 0.0006x 2 - 0.0775x + 4.0487 4 R 2 = 0.9995 3.5 k w 3 Log (k') log k 2.5 2 1.5 1 y = -0.0283x + 2.1268 0.5 R 2 = 0.9987 0 0 10 20 30 40 50 60 70  (% of Organic Modifier) % Organic Solvent    log log P a k bS c W S is the slope of the linear regression, a, b, c are characteristics of the S.Ph. K. Valko, V. Slegeli, J. Chromatogr. A, 631 (1993) 49-61.

6 y = 0.9687x + 0.1304 R 2 = 0.9831 5 Chromatographic Log P Model set of compounds 4 Target compound 3 2 1 0 0 1 2 3 4 5 6 Known Log P

O O O P O O P O + + N N O O O O O O O O O O O O O O H N H N H N H N Si Si Si Si O O O O O O O O O O O O IAM.PC IAM.PC.DD2 C. Pidgeon, et al., J. Med. Chem., 38 (1995) 590-594.

The CHI scale : % (v) of ACN required to achieve an equal distribution of the compound between M.Ph. and S. Ph. Gradient elution conditions! log k   W t f ( ) R S K. Valko, C. Bevan, D. Reynolds, Anal. Chem., 69 (1997) 2022-2029.

160.00 y = -411.11x + 140.45  R 2 = 0.9994 k log P   ( 0 ) y = -93.271x + 35.956 140.00 2 = 0.9992 R y = -44.822x + 18.093 R 2 = 0.9991 120.00 MP y = -21.925x + 9.0938 EP R 2 = 0.9993 100.00 PP y = -10.715x + 4.5966 BP R 2 = 0.9988 PeP y = -5.045x + 2.3482 80.00 k R 2 = 0.9969 HP OP y = -2.2946x + 1.2665 R 2 = 0.9928 60.00 40.00 20.00 0.00 0 0.05 0.1 0.15 0.2 0.25   (V inj /V 0 ) C. Sarbu, R.D. Nascu-Briciu, D. Casoni, A. Kot-Wasik, J. Namiesnik, J. Chromatogr. A, 1266 (2012) 536-544.

Inhibited Enzyme Enzyme AChE AChE O (S) O (S) + Ser OH Ser O P R3 R 1 O or X P R3 - R 1 OH or HX (X = F, CN) O(S)R 2 O(S)R 2 Oximate AChE AChE O (S) - H O -H + O - + Ser Ser O P R3 O N N N + + H + N + O(S)R 2 Quaternary Reactivated Ammonium Enzyme Oxime + O (S) R 2 (S)O P R3 O N N + Oxime - Inhibitor Complex V. Voicu, F.S. Radulescu, D., A. Medvedovici, EOMT, 9 (2013) 31-50.

Aged inhibited Enzyme Time of E PO - ageing Biodistribution Access to the inhibited site Minimum extent of Structural Biodistribution diversity Access to the esteratic site Intrinsic reactivation Ageing toxicity granting survival Phosphylated OP inhibited Active Complex Oxime Enzyme Enzyme Reactivation Intoxication + + + E P E P O E P P O O E OP agent re-inactivation rate Oxime Half life Detoxication Spontaneous Structural Reactivation diversity Intrinsic toxicity AChE POH + + E P O POH

    Log(BB)  [-2  1] (1) A  Brain   Log ( BB )   Favorable distribution: Log(BB) > 0.3;   A Poor Distribution: Log(BB) < -1; Blood SS Log(BB) = f ( molecular mass – Mw; hydrophobic character – log P; polar surface area – PSA; n o . of rotatable bonds; n o . of H-bond donors; n o . of H-bond acceptors; 3D-molecular field descriptors; electropological state indices; critical micelle concentration – CMC D ; cross sectional area – A D ; permeability coefficient – PC; polarizability – CMR … and others ) Successful CNS Drug (2) Descriptor Condition Descriptor Condition Molecular weight Mw < 450 Water solubility S > 60  g/mL Hydrophobic character Log P < 5 Metabolic stability > 80% after 1 h No. of H-bond donor P450 enzyme CIP inhibition  3 < 50% at 30  M No. of H-bond acceptor < 7 Metabolization by CYP2D6 Not significant No. of rotatable bonds < 8 CYP3A4 inducer No potent PSA < 60  70 Å 2 Polar surface area P-glycoprotein substrate No H-bonds <8 Affinity to serum albumin K D < 10  M > 1  10 -6 cm/sec Acid character pK a  [7.5  10.5] Effective permeability (1) M.H. Abraham et al., J. Pharm.Sci., 86 (1992) 310-315. (2) H. Pajouhesh, G.R. Lenz, NeuroRx  , 2 (2005) 541-553.

O O N + + N N N O 2 I - N N N O + + N OH C2 O OH RP (C8); IP (C8); RP (PFP); PRDS N PAM (Pralidoxime) (Pyridostigmine) HILIC; ZIC-HILIC; AGP O + N N O N 2 I - NH 2 O + C3 + + N O N OH N HI-6 H O N O + N I - N Elution at 37 o C, with 0.9% N NH 2 + + OH OH N N O N HLo-7 C4 NaCl in the aqueous H O N component of the M.Ph. N N + + OH O N OH N LuH-6 (Obidoxime) V. Voicu, I. Sora, C. Sarbu, V. David, A. Medvedovici, J. Pharm. Biomed. Anal., 52 (2010) 508-516.

Position of Substituent (R) Substituent (R) # the oxime Acronym(s) Name Formula moiety OH 1 Ethyl -C 2 H 5 2, 3, 4 2-PAE, 3-PAE, 4-PAE 2 Butyl -C 4 H 9 2, 3 2-PAB, 3-PAB N 3 Hexyl -C 6 H 13 2, 3, 4 2-PAH, 3-PAH, 4-PAH 4 Octyl -C 8 H 17 2, 3, 4 2-PAO, 3-PAO, 4-PAO 5 Decyl -C 10 H 21 2, 3 2-PAD, 3-PAD 6 Dodecyl (Lauryl) -C 12 H 25 2, 3, 4 2-PAL, 3-PAL, 4-PAL + N 7 Benzyl -CH 2 -C 6 H 5 2, 3, 4 2-PABn, 3-PABn, 4-PABn 8 Ethyl-phenyl -(CH 2 ) 2 -C 6 H 5 2, 3, 4 2-PAPE, 3-PAPE, 4-PAPE R 9 Propyl-phenyl -(CH 2 ) 3 -C 6 H 5 3 3-PAPP 10 Butyl-phenyl -(CH 2 ) 4 -C 6 H 5 3, 4 3-PAPB, 4-PAPB 11 4-Methylbenzyl -CH 2 -C 6 H 4 -CH 3 2, 3, 4 2-PAMB, 3-PAMB, 4-PAMB 12 4- t -Butylbenzyl -CH 2 -C 6 H 4 -C(CH 3 ) 3 3, 4 3-PATB, 4-PATB H. Ohta, T. Ohmori, S. Suzuki, H. Ykegaya, K. Sakurada, T. Takatori, Pharm. Res., 23 (2006) 2827-2833.

H O Stationary Phase H O O H H O H H O H O H Mobile Phase Alkyl Layer Aqueous Layer A Aqueous L. A M.Ph. Si O O O A Alkyl L.

25.00 bin k W + N N H O 20.00 lin k w 15.00 HYL k 10.00 k min 5.00 ISOELUT 0.00 0.00 20.00 40.00 60.00 80.00 100.00 k  (   f ) (%ACN)

3.1000 bin log k W 2.9000 H O N 2.7000 + N 2.5000 2.3000 2.1000 1.9000 log k 1.7000 lin log k w 1.5000 LOGHYL 1.3000 1.1000 log k min 0.9000 0.7000 LOGISOELUT 0.5000 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0 k    log f ( ) (% ACN)

35.00 y = -1.05744 x + 38.96723 y = 0.0097x 2 - 1.1351x + 36.865 R 2 = 0.9497 R 2 = 0.9321 30.00 b   ISOELUT 2 a 25.00  ( a a )  2 1 1 ISOELUT H O  ( ) 20.00 b b 1 2 N k a   ( 1 ( b b ) 2 ISOELUT 2 ( ) 1 2 15.00 a + N 1 y = 413.9 x -1.1072 10.00 R 2 = 0.9730 y = 2E-05 x 2.9679 5.00 R 2 = 0.9579 y = 0.32577 x - 17.5287 R 2 = 0.9344 0.00 0 10 20 30 40 50 60 70 80 90 100  (%ACN)

50 3-PAL-BR (70% Solv. B) 3-PAD-BR (70% Solv. B) 3-PAO-BR (70% Solv. B) 3-PAH-BR (70% Solv. B) 3- PAB-BR (50% Solv. B) 3-PAE-I (30% Solv. B) 0 0 2 4 6 8 10 12 14 16 18 min

50 3-PAPB-BR (70% Solv. B) 3-PATB-BR (70% Solv. B) 3-PAMB-BR (60% Solv. B) 3-PAPP-BR (60% Solv. B) 3-PAPE-BR (60% Solv. B) 3-PABN-BR (50% Solv. B) 0 0 2 4 6 8 10 12 14 16 18 min