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Drug discovery and development is a very challenging, expensive and time-consuming process. Impressive technological advances in computer sciences and molecular biology have made it possible to use computer-aided drug design (CADD) methods in various stages of the drug discovery and development pipeline. Nowadays, CADD presents an efficacious and indispensable tool, widely used in medicinal chemistry, to lead rational drug design and synthesis of novel compounds. In this article, an overview of commonly used CADD approaches from hit identification to lead optimization was presented. Moreover, different aspects of design of multitarget ligands for neuropsychiatric and anti-inflammatory diseases were summarized. Apparently, designing multi-target directed ligands for treatment of various complex diseases may offer better efficacy, and fewer side effects. Antipsychotics that act through aminergic G protein-coupled receptors (GPCRs), especially Dopamine D2 and serotonin 5-HT2A receptors, are the best option for treatment of various symptoms associated with neuropsychiatric disorders. Furthermore, multi-target directed cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) inhibitors are also a successful approach to aid the discovery of new anti-inflammatory drugs with fewer side effects. Overall, employing CADD approaches in the process of rational drug design provides a great opportunity for future development, allowing rapid identification of compounds with the optimal polypharmacological profile.

Acetylsalicylic acid belongs to nonsteroidal anti-inflammatory drugs with antiinflammatory, analgesic and antipyretic properties. The aim of this work was development and validation of HPLC method for qualitative and quantitative analysis of acetylsalicylic acid and its major degradation product, salicylic acid, in dosage forms. The optimal separation was achived using Zorbax Eclipse XDB-C18 Analytical column (4,6x150 mm, particle size 5 μm) thermostated at 35°C. Mobile phase consisted of eluents A and B in ratio 65:35 (V/V). As the eluent A, water of HPLC purity and 85% phosphoric acid in ratio 80:0.5 (V/V) were used, while acetonitrile was used as the eluent B. The flow rate was 1.0 mL/min and UV detection was performed at 240 nm. The method was validated in terms of selectivity, linearity, precision, accuracy and robustness for both analytes, as well as limits of detection and quantification for salicylic acid. The obtained results meet the requirements of analytical procedures validation. The proposed HPLC method was applied in qualitative and quantitative analysis of acetylsalicylic and salicylic acids in six different forms of drugs. All obtained results meet the requirements of manufacturer specifications. The established HPLC method was found to be rapid, simple, accurate and selective for simultaneous determination of acetylsalicylic and salicylic acids in dosage forms.

Acridine ring can be found in molecules used in many different spheres, including industry and medicine. Nowadays, even acridines with antibacterial activity are of research interest due to increasing bacterial resistance. Some acridine derivatives showed antimalarial or antiviral activity. Acridine derivatives were also investigated for antitumor activity due to the interaction with topoisomerase II and DNA base pairs. Considering these possible uses of acridine derivatives, this work was made as overview of all significant structure characteristics for specific action of these compounds.

Cortienic acid was obtained by periodic acid oxidation of fluocinolone acetonide, whereas corresponding amide was synthesized from the cortienic acid and ethyl ester of b-alanine by dicyclohexylcarbodiimide - hydroxybenzotriazole coupling procedure. Lipophilicity of the amide was evaluated by using reversed-phase thin-layer chromatography systems, consisting of ethanol and water in various ratios, and was higher in comparison to fluocinolone acetonide and cortienic acid.

L-phenylalanine methyl ester derivative of dexamethasone - derived cortienic acid (DF) was synthesized and its crystal structure was characterized by X-ray diffraction method. The crystal system is orthorhombic with space group P212121 and cell constants a = 8.2969 (3) Å, b = 18.9358 (8) Å, c = 20.0904 (6) Å, V = 3156.4 (2) Å3 and Z = 4. Ring A of the steroid nucleus and phenyl ring in the 17β-side chain are almost planar. Rings B and C have a slightly distorted chair conformation, whereas ring D has an envelope conformation. The packing of DF is characterized by a network of intermolecular hydrogen bonds involving the O4 atom from one side of the steroid nucleus and O1 and F1 atoms from the other side as hydrogen bond acceptors. Apart from the intermolecular hydrogen bonds in the crystal packing, there are also numerous intramolecular hydrogen bonds of the N-H...O, C-H...O and C-H...F type. Local anti-inflammatory activity of DF was evaluated by use of croton oil-induced ear edema test. This derivative achieved maximal inhibition of ear edema at significantly lower concentration in comparison with dexamethasone. [Projekat Ministarstva nauke Republike Srbije, br. 172041, 172014 i 172035]

Soft ('antedrug') glucocorticoids are pharmacologically active compounds which are biotransformed in a predictable and controllable way to inactive and non-toxic metabolites. Amides of cortienic acids (17(-carboxamide derivatives of glucocorticoids) are potential soft drugs with fewer side effects than traditional glucocorticoids. The purification of 17(- carboxamide derivatives of hydrocortisone was explained using the amide of hydrocortisonederived cortienic acid and ethyl ester of L-glycine as an example and performed by use of column chromatography and preparative thin-layer chromatography (TLC). The optimization of purification process was performed employing analytical TLC and reversed-phase highperformance liquid chromatography (RP-HPLC). The mobile phase that enables best chromatographic separation of the amide from impurities on TLC plate (chloroform-methanol (95:5 V/V)) was selected and modified (reduction of polarity and addition of glacial acetic acid) to be used for the column chromatography and preparative TLC purification. It was confirmed by use of RP-HPLC that purification procedures applied in this study resulted in pure (96.2 %) amide.

A simple and sensitive reversed-phase, ion-pair HPLC method was developed and validated for the simultaneous determination of B-group vitamins, thiamine chloride hydrochloride (B1), nicotinamide (B3), pyridoxine hydrochloride (B6) and folic acid in Pentovit® coated tablets. The cyanocobalamine (B12) was determined separately, because of its low concentration in the investigated multivitamin preparation. RP-HPLC analysis was per- formed with a LKB 2150 HPLC system, equipped with a UV/VIS Waters M 484 detector. The procedures for the determination of B1, B2, B6 and folic acid were carried out on a Supelcosil ABZ+ (15 cm 4.6 mm; 5 m) column with methanol-5mM heptanesulphonic acid sodium salt 0.1 % triethylamine TEA (25:75 V/V); pH 2.8 as the mobile phase. For the determination of B12 a Suplex pKb-100 (15 cm 4.6 mm; 5 m) column and methanol–water (22:78 V/V) as the mobile phase were used. The column effluents were monitored at 290 nm for B1, B3, B6 and folic acid, and at 550 nm for B12. The obtained results and statistical parameters for all the investigated vitamins of the B-group in Pentovit® coated tablets were satisfactory and ranged from 90.4 % to 108.5 % (RSD. from 0.5 % to 4.1 %). The parameters for the validation of the methods are given.

The proposed method for the determination of fluocortolone is based on the formation of a stable, yellow coloured hydrazone product with 1,4-dihydrazinophthalazine as the reagent. Heating at 85°C for 2 h was found to be necessary to ensure optimal hydrazone formation in acidified 1-propanol as the solvent. The detection limit was 1.2 µg/ml. This method when applied for the determination of fluocortolone in pharmaceutical formulations gave precise and reproducible results.