i c a l

P

Md

HL

1

F2

F

iiCqfimetsaaaiuin

d

P

Scf

P

1

2

l

aFcsbsaweliSFilt

d

e u r o p e a n j o u r n a l o f p h a r m a c e u t

33

olecular modeling of prostate specific antigen (PSA) and theesign of compounds modulating its activity

.H. Harkonen 1,∗, E.A.A. Wallen 2, B. Windshugel 1, M.ahtela-Kakkonen 1, A. Poso 1

Department of Pharmaceutical Chemistry, University of Kuopio,inlandDepartment of Pharmaceutical Chemistry, University of Helsinki,inland

Prostate cancer is the most common cancer of males inndustrialized countries. Its incidence has increased signif-cantly due to PSA screenings and aging of the population.ommon drug therapy has side effects affecting the patients’uality of life and some of the drugs eventually become inef-cient. The objective of this research is to develop new drugolecules using computer-aided drug design (CADD). CADD is

xtremely important method in modern drug design. Recently,he crystal structure of PSA was published. However, crystaltructures with bound ligands still lack. As such, a compar-tive model of PSA is developed using molecular modelingnd dynamics. With the protein model, binding modes of PSActivating cyclic peptides are studied using molecular dock-ng. Moreover, together with the crystal structure PSA model issed for virtual screening of novel drug candidates. Successful

n silico models make it possible to predict the pharmacoki-etic profile of novel drug candidates.

oi:10.1016/j.ejps.2008.02.110

34

olvent-mediated solid phase transformations ofarbamazepine—Effects of simulated intestinal fluid andasted state simulated intestinal fluid

. Lehto 1,∗, J. Hirvonen 2, L. Peltonen 2

Orion Pharma, FinlandDivision of Pharmaceutical Technology, University of Helsinki, Fin-

and

Solvent-mediated transformations of carbamazepinenhydrate (CBZ (A)) were investigated in Simulated Intestinalluid, a simple USP buffer medium, and in FaSSIF, whichontains sodium taurocholate (STC) and lecithin. Ramanpectroscopy (in situ) was utilized to reveal the connectionetween the changes in solid phase composition and dis-olution rate while simultaneously detecting the solid statend the dissolved amount of CBZ. Initial dissolution rateas higher in FaSSIF due to better wetting and solubilization

ffects, while the solid phase data revealed that the crystal-ization of carbamazepine dihydrate (CBZ (D)) was inhibitedn both dissolution media, albeit by different mechanisms. InIF this inhibition was related to extensive needle growth, inaSSIF to plate-like counterparts. These results underline themportance of biologically representative dissolution media

inking the in vitro dissolution results of metastable solids toheir in vivo dissolution behaviour.

oi:10.1016/j.ejps.2008.02.111

s c i e n c e s 3 4 S ( 2 0 0 8 ) S30–S41 S39

P35

Developing an extended compartmental absorption and tran-sit model for per oral controlled drug delivery

J. Marvola 1,∗, A. Urtti 2, M. Yliperttula 3

1 Industrial Pharmacy, Faculty of Pharmacy, University Of Helsinki,Finland2 DDTC, University of Helsinki, Finland3 Division of Biopharmaceutics and Pharmacokinetics, University ofHelsinki, Finland

Computational methods have potential to decrease thelength of time prior to submissions to regulatory authoritiesand to reduce the number of experiments in drug devel-opment. A pharmacokinetic compartmental absorption andtransit model (CAT) is useful in predicting the per oral drugabsorption in the small intestine. For controlled delivery, it isnecessary to expand the model to take into account releaseand absorption in the colon. In this work, an extended CATmodel was built based on pharmacoscintigraphic studies of acontrolled release (CR) delivery system. Three colon segmentcompartments were introduced in the model. The extendeddesign allows modeling of formulation transit, controlled drugrelease and absorption in the entire colon. The simulatedplasma profiles were correlated with the in vivo findings.New model was tested by varying the parameters for transit,absorption and elimination. The model is useful in assessingthe potential kinetics of CR medication.

doi:10.1016/j.ejps.2008.02.112

P36

Utilizing ion mobility spectrometry combined with massspectrometry for analysis of pharmaceutical compounds

T. Mauriala 1,∗, A. Adamov 2, J. Laakia 2, A. Sysoev 3, T.Kotiaho 2,4, R. Ketola 1

1 Drug Discovery and Development Technology Center, Faculty ofPharmacy, University of Helsinki, Finland2 Laboratory of Analytical Chemistry, Department of Chemistry, Uni-versity of Helsinki, Finland3 Moscow Engineering Physics Institute, State University, Russia4 Division of Pharmaceutical Chemistry, Faculty of Pharmacy, Uni-versity of Helsinki, Finland

Drift tube ion mobility spectrometry (IMS) is a time-of-flighttechnique which utilizes the characteristic ion mobilities ofthe gas phase ions for separation and detection of chemi-cal species. In IMS instrument an applied drift voltage drivesions through drift tube where collisions occur between ionsand neutral drift gas molecules. The separation of compoundsis achieved based upon the different drift times of the ionsthrough the drift tube. The drift time of an ion dependson its characteristic ion mobility. Furthermore, the mobilityof an ion in an inert gas depends on the charge, reducedmass and collision cross section of the ion. In this study a

self-made IMS instrument combined with commercial triplequadrupole mass spectrometer (IMS-MS) was utilized for anal-ysis of pharmaceutical compounds. Four drugs (verapamil,metoprolol, propranolol and antipyrine) were chosen for the

u t i c

S40 e u r o p e a n j o u r n a l o f p h a r m a c e

analysis. The detection limit of ∼10 nM was reached for allanalytes.

doi:10.1016/j.ejps.2008.02.113

P37

Retarding the kinetics of theophylline hydrate formationusing pharmaceutical excipients

I. Miroshnyk 1,∗, S. Mirza 1, J. Heinamaki 1, J. Aaltonen 2, J.Yliruusi 1

1 Division of Pharmaceutical Technology, Faculty of Pharmacy, Uni-versity of Helsinki, Finland2 School of Pharmacy, University of Otago, New Zealand

Hydrate formation is a common phase transformation thatpharmaceutical solids may undergo during manufacturingprocesses or storage. The resulting solid-state changes cancause severe problems in the processing and/or performanceof pharmaceutical products and thus these changes must beprevented. This study investigates the effect of pharmaceu-tically accepted excipients on hydrate formation kinetics oftheophylline anhydrate. Theophylline anhydrate was modi-fied by recrystallization in the presence of an excipient (HPMC,PVP or HPC) as an additive in the crystallization media. Themorphology of the excipient-modified crystals was diverseand differed from that of the unmodified theophylline, asobserved by optical microscopy. Furthermore, the hydrateformation kinetics in wet masses containing the modifiedcrystals was retarded as compared with that of unmodi-fied crystals, as revealed by quantitative Raman spectroscopy.Hence, this study demonstrates that excipient-induced sur-face and/or habit modification of crystals is a promisingapproach to controlling hydrate formation of pharmaceuticalsolids.

doi:10.1016/j.ejps.2008.02.114

P38

In silico screening of potential crystal growth inhibitors forthe stabilization of amorphous structures

K. Pajula 1, M. Lahtela-Kakkonen 2, O. Korhonen 1,∗

1 Department of Pharmaceutics, University of Kuopio, Finland2 Department of Pharmaceutical Chemistry, University of Kuopio,Finland

The aim of this study was to evaluate the applicability ofreceptors based docking softwares for the virtual screening ofpotential crystal growth inhibitors. In study set up, unit cellsof acetaminophen and naproxen were obtained from Cam-bridge structural database. The fastest growing crystal faceswere determined using Morphology toolbox (Accelrys). Crystalgrowth sites, as receptors, in several fastest growing faces weregenerated by deleting some molecules from faces. For modelligands, as inhibitors, were selected all amino acids and dipep-

tides. As an “internal standard” was used acetaminophenand naproxen. Ligands were docked to growth sites (receptor)using MOE (Chemical Computing Group) and Sybyl Surflex-Dock (Tripos) docking suites. Applicability of docking suites in

a l s c i e n c e s 3 4 S ( 2 0 0 8 ) S30–S41

small molecule docking on crystal faces was evaluated accord-ing to internal standards. Surflex-Dock suite docked perfectlyacetaminophen and naproxen molecules into their own crys-tal lattices, thus pointing out the powerful applicability of it innovel screening approach.

doi:10.1016/j.ejps.2008.02.115

P39

Betulin derivatives inhibit Alphavirus replication

L. Pohjala 1,2,∗, S. Alakurtti 3,4, J. Yli-Kauhaluoma 3, T. Ahola 5,P. Tammela 1

1 Drug Discovery and Development Technology Center (DDTC), Fac-ulty of Pharmacy, University of Helsinki, Finland2 Division of Pharmaceutical Biology, Faculty of Pharmacy, Universityof Helsinki, Finland3 Division of Pharmaceutical Chemistry, Faculty of Pharmacy, Uni-versity of Helsinki, Finland4 Technical Research Centre of Finland, VTT, Finland5 Institute of Biotechnology, University of Helsinki, Finland

Betulin is a widespread naturally occurring triterpenene,found in large quantities in birch bark. Despite the knowl-edge on betulin-derived compounds as anti-HIV agents, theirwider antiviral spectrum remains poorly studied. In this study,a set of 68 betulin derivatives was screened against Sem-liki Forest virus (SFV), a member of Alphavirus genus and acommonly used model for replication of positive-strandedRNA viruses. The basic structure of betulin was moderatelyactive against SFV (IC50 45 �M), but antiviral potency wasenhanced particularly by certain cyclic ether or ester sub-stituents, as demonstrated by 28-O-tetrahydropyranylbetulinand 3,28-betulinyl di(2-sulfobenzoate) (IC50 values 17 and11 �M, respectively). Even though some derivatives raised alsotoxic responses in Huh-7 cells, therapeutic indices higher than50 were obtained for many of the tested compounds. Dueto their non-nucleoside structure and relatively low toxicity,betulin-derived compounds make a competitive contributionto the few inhibitors of these pathogens.

doi:10.1016/j.ejps.2008.02.116

P40

The effect of differentiation on the expression of UGT isoen-zymes in Caco-2 cell line

S. Siissalo ∗, H. Zhang, J. Hirvonen, M. Finel

University of Helsinki, Finland

As a part of the characterization process of Caco-2cell line, the expression of different UGT (UDP-glucuronosyltransferase) enzymes was studied. The mRNAlevels of 15 UGT1A and UGT2B isoforms were determined inseveral samples of Caco-2 cells (four passage levels: P31, P37,P43 and P49, fully differentiated cells grown on filters and

undifferentiated cells obtained from culturing flasks) usingquantitative real-time RT-PCR. The expression levels werenormalized using �-actin as a reference gene. The differencein the degree of differentiation was demonstrated with villin