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-11enetration of drugs through skin: Latest developments

.T. Degim

University of Gazi, Faculty of Pharmacy, Department of Pharmaceu-ical Technology, 06330 Etiler, Ankara, Turkey

-mail address: tunc@tr.net.

here have been considerable developments in our knowl-dge about the physiology, function and mechanism of skinermeation. This has largely been brought about by the devel-pment of experimental techniques and increased computerechnology, hardware and available softwares. The advancedomputer technology and software have provided indications,elationships, at a molecular level, about routes of penetrationnd how the formulations can be formulated considering theffects of excipients and drugs on the barrier properties of skinayers.

Available computer programs for molecular modeling haveeen used to calculate some molecular properties of drugolecules such as surface area, partial charges, etc. This oral

resentation will review some experimental techniques inkin research, some of the mathematical models and tech-iques used some molecular descriptors and some propertiesf the penetrant that have been constructed to predict andnderstand percutaneous penetration and transdermal deliv-ry. The models are also useful for various enhancementtrategies that can be used in dermal penetration and for-ulation development studies. If the appropriate biophysical

echniques combined with the mathematical modeling andtatistical analysis using computer, it can provide useful infor-ation for identifying the possible penetration processeshen different classes of enhancers or excipients used in the

ormulation. Models are also useful for understanding whichactors affect the penetration of molecules through skin andhese factors/parameters can be used for the control of theenetration rate when effective transdermal delivery or ther-py is required or targeted.

oi:10.1016/j.ejps.2007.05.022

-12ifferent emulsion systems for drug and cosmetic delivery

¨ . Ozer

Ege University, Department of Pharmaceutical Technology, 35100ornova, Izmir, Turkey

-mail address: ozgen.ozer@ede.edu.tr.

mulsions are one of the oldest pharmaceutical systems. Theyre still one of the most useful systems in pharmaceuticalnd especially cosmetic field. Either the dispersed phase orhe continuous phase may range in consistency from thatf a mobile liquid to a semisolid. Thus, emulsified systemsange from lotions of relatively low viscosity to ointments andreams, which are semisolid in nature.

The emulsion is defined as the dispersion of one immiscibleiquid in another, stabilized by a third component, the emul-ifying agent. The dispersed liquid or internal phase usuallyonsists of globules of diameters down to 0.1 �m which are

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distributed within the external or continuous phase. Both ofthe classical types of emulsions-oil-in-water (o/w) and water-in-oil (w/o) are used as pharmaceutical and cosmetic systems.However more complex forms including multiple emulsions(w/o/w or o/w/o) have been also described in the literature.Multiple emulsions are the systems wherein droplets of thedispersed phase contain additional but smaller droplets, iden-tical to or different from the continuous phase. If the dispersedglobules are of colloidal dimensions (1 nm to 1 �m diameter),the preparation, which is quite often transparent, is calleda microemulsion. Miceoemulsions are clear, isotropic, ther-modynamically stable dispersions of two immiscible liquidscreated by the presence of a suitable surfactant, usually inconjunction with a cosurfactant. Both multiple emulsionsand microemulsions are promising systems for pharmaceu-tical and cosmetic industry. They have been shown to beable to protect active material, control release, increase drugsolubility. Furthermore, it is possible to formulate differentpreparations for different routes of administration with them.

Emulsion systems could be delivered by three main differ-ent routes: parenteral, oral and topical. They have also beenused by pulmonar and ophthalmic routes. The emulsions fororal administration are usually of the o/w type, especiallywhen the dispersed phase has an unpleasant taste. More sig-nificant, some oil soluble compounds, such as some of thevitamines, are observed more completely when emulsifiedthan when administered orally as an oily solution. Parenterallipid emulsions have been used as a source of energy, as vehi-cles for drug delivery for controlled release and the targeting ofdrugs to specific sites in the body. Topical emulsions can alsobe applied to the external surfaces of the body and body cav-ities. They are exciting formulations for pharmaceutical andcosmetic field with their microstructure effects.

doi:10.1016/j.ejps.2007.05.023

O-13Implementation of pharmaceutical care into communitypharmacy practice

D. Volmer a, D. Hamilton b

a Institute of Pharmacy, University of Tartu, Estoniab RAPS, University of Glasgow, Scotland, UK

E-mail address: daisy.volmer@ut.ee (D. Volmer).

According to Strand and Hepler pharmaceutical care (PC) isdefined as the responsible provision of drug therapy for thepurpose of achieving definite outcomes which improve thepatient’s Quality of Life (Hepler and Strand, 1990). PC can bedescribed as activities provided at hospital and communitypharmacies to prevent and/or solve drug-related problems. Anideology of PC has been accepted and approved by the healthauthorities in many countries. But problems appear when the-ory is implemented in practice.

What are the pros and cons of putting PC into practice inthe community pharmacies of Estonia?

Advantages in developing a PC service:

• According to the Medicinal Products Act it is obligatory tocounsel patients at the pharmacy to promote the rationaluse of medicines.

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• At a private pharmacy work can be organized to be moreflexible and to make essential changes to pharmacy ser-vices, e.g., providing a PC service.

• Patients already appreciate pharmacists as a valuablesource for information about medicines. A PC service willpromote this further.

• With the help of the EuroPharm Forum Estonian phar-macists will have the opportunity to participate inmultinational projects to improve the quality of the phar-macy service.

Disadvantages in developing PC service:

• The requirements in the Medicinal Products Act regardingthe provision of drug information at the pharmacy are verygeneral. More precise details on how to implement PC ser-vices will be required.

• As ownership of a pharmacy is not limited to people witha pharmacy education, the main goal of private pharmacycan be to make a profit rather than provide a quality phar-macy service. At many pharmacies in Estonia the numberof personnel is the absolute minimum so it will be difficultto offer extended services.

• At the pharmacy patients mostly receive information aboutdrug administration. Details of side effects and interactionsof medicines are seldom given. There is no tradition of pay-ing any fee for extended services at pharmacy.

• International projects have been one-offs and what hasbeen learned from them has very seldom been used ineveryday practice.

In Estonia there is now the opportunity to implement PCservices into community pharmacy practice. However, it ispremature to talk of providing PC services for patients withparticular diseases. At present what is important is to concen-trate on standardizing the quality of pharmacy services andteaching the principles of clinical pharmacy to our pharmacystudents.

e f e r e n c e

Hepler, C.D., Strand, L.M., 1990. Am. J. Hosp. Pharm. 47, 533–543.

doi:10.1016/j.ejps.2007.05.024

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O-14Screening against Staphylococcus aureus biofilms using a 96-microtiter well plates assay: An automated approach

A. Fallarero a, M. Sandberg a, A. Maattanen b, J. Peltonen b,P. Vuorela a

a Department of Biochemistry and Pharmacy, Abo Akademi Univer-sity, FIN-20520 Abo, Finlandb Department of Physical Chemistry, Abo Akademi University,FIN-20500 Abo, Finland

Discovery of new antimicrobial drugs has been progressivelydemanding the development of reliable techniques allowingthe testing of bioactivity against biofilm infections. However,no standard method for investigating the drug susceptibilityof biofilms has been established yet. Our group has startedto address this problem by optimizing a manual Staphylococ-cus aureus model of biofilm formation in 96-microtiter wellplates. In order to allow the screening of large libraries, cur-rent project was aimed to perform the full automation of this96-microtiter well plates model of S. aureus biofilms, using acombination of Thermo Combi Multidrop dispenser (Md dis-penser) and Biomek 3000 environments. S. aureus (DSM 20231)was grown during 4 h at 37 ◦C, 200 rpm in Tryptic Soy Broth.Bacterial suspensions (106 CFU/ml) were dispensed into platesusing the Md dispenser, and allowed to form biofilms during18 h at 37 ◦C, 200 rpm. Then, bacterial biofilms were quanti-tatively stained using crystal violet. All the pipetting stepswere performed using Biomek 3000, with the exception of thestaining step which was carried out using the Md dispenser.A comparison was then made with a totally manually per-formed assay. In parallel, visualization and characterizationof the bacterial biofilms formed under these experimentalconditions was conducted using Atomic Force Methodology(tapping mode). A detailed comparison between the manualand the automated assays was done, in terms of screen-ing window coefficient (Z′ factor), signal-to-background (S/B),signal-to-noise parameters (S/N), separation band parame-ters, repeatability measures (well-to-well, plate-to-plate andday-to-day) and DMSO sensitivity. Results shown that whencompared to the manual approach, the fully automatedscreening assay has comparable quality parameters (Z′ = 0.45,S/N = 6.9 and S/B = 5.3) but the plate-to-plate (0.6%) and theday-to-day (8.9) variations are significantly lower. The relia-bility of the automated assay was also tested by performing avalidating screening of 49 compounds and the results were inagreement with literature reports. In summary, current projectfavour the use of this automated 96-microtiter well plates

model of S. aureus biofilms for the bioactivity profiling of nat-ural or synthetic compounds.

doi:10.1016/j.ejps.2007.05.025