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  • Author: Blanka Székely-Szentmiklósi x
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Open access

Blanka Székely-Szentmiklósi and B Tőkés

Abstract

Introduction: In the present work we evaluated the complexation role of cyclodextrins toward fluoroquinolones in an attempt to assess their potential as new formulation additives for more efficient fluoroquinolone delivery and as selectors in capillary electrophoresis.

Material and method: Guest-host interactions of two second generation quinolones, ciprofloxacin and norfloxacin with four cyclodextrins, beta-cyclodextrin (β-CD), gamma-cyclodextrin (γ-CD) and two beta-cyclodextrin derivatives, 2-hydroxypropyl beta-cyclodextrin (HP-β-CD) and randomly methylated beta-cyclodextrin (RAMEB), were tested by capillary electrophoresis in borate running buffer. Experimental parameters like buffer concentration, pH, organic modifier, voltage and cyclodextrin concentration have been varied for a better resolution.

Results: In capillary zone electrophoresis ciprofloxacin and norfloxacin are migrating together, a difference in their migration times and thus separation occured by the addition of cyclodextrins.

Conclusion: Our results suggest formation of inclusion complexes between fluoroquinolones and cyclodextrins. Differences in their affinity to host molecules resulted in separation of the two fluoroquinolones

Open access

Kelemen Hajnal, Hancu Gabriel, Rusu Aura, Varga Erzsébet and Székely Szentmiklósi Blanka

Abstract

Prodrugs are chemically modified derivatives introduced in therapy due to their advantageous physico-chemical properties (greater stability, improved solubility, increased permeability), used in inactive form. Biological effect is exerted by the active derivatives formed in organism through chemical transformation (biotransformation). Currently, 10% of pharmaceutical products are used as prodrugs, nearly half of them being converted to active form by hydrolysis, mainly by ester hydrolysis. The use of prodrugs aims to improve the bioavailability of compounds in order to resolve some unfavorable characteristics and to reduce first-pass metabolism. Other objectives are to increase drug absorption, to extend duration of action or to achieve a better tissue/organ selective transport in case of non-oral drug delivery forms. Prodrugs can be characterized by chemical structure, activation mechanism or through the presence of certain functional groups suitable for their preparation. Currently we distinguish in therapy traditional prodrugs prepared by chemical derivatisation, bioprecursors and targeted delivery systems. The present article is a review regarding the introduction and applications of prodrug design in various areas of drug development.

Open access

Zoltán-István Szabó, Blanka Székely-Szentmiklósi, Boglárka Deák, István Székely-Szentmiklósi, Béla Kovács, Katalin Zöldi and Emese Sipos

Abstract

To evaluate the influence of different variables on tablet formulations containing enalapril maleate and indapamide as active substances, two separate experimental designs were employed: one for evaluating powder properties and the other for tablet characteristics. Because of the low active pharmaceutical ingredient content, it was hypothesized that both powder and tablet properties could be determined only by the characteristics of excipients. In order to test this assumption, both experimental designs were done with placebo mixtures. The optimized formulation was then evaluated both with and without APIs. Results indicated that filler and lubricant percentage, along with compression force, were the most important variables during the formulation study. The optimized formulation showed similar characteristics in both cases for all responses, except for angle of repose and friability where only minor differences were observed. The combination of the applied approaches (using placebo composition and fractional experimental design) proved to be efficient, cost effective and time saving.

Open access

Béla Kovács, Előd Ernő Nagy, Norbert Nándor Chendrean, Blanka Székely-Szentmiklósi and Árpád Gyéresi

Abstract

As musculoskeletal diseases become an emerging healthcare problem worldwide, profound and comprehensive research has been focused on the biochemistry of bone metabolism in the past decades. Wnt signalling, one of the novel described pathways influencing bone metabolism from the early stages of tissue development, has been recently in the centre of attention. Several Wnt ligands are implied in bone forming pathways via canonical (β-catenin dependent) and non-canonical (β-catenin independent) signalling. Osteoporosis, a catabolic bone disease, has its pathologic background related, inter alia, to alterations in the Wnt signalling, thus key modulators of these pathways became one of the most promising targets in the treatment of osteoporosis. Antibodies inhibiting the activity of endogenous Wnt pathway inhibitors (sclerostin, dickkopf) are recently under clinical trials. The current article offers a brief review of the Wnt signalling pathways, its implication in bone metabolism and fate, and the therapeutic possibilities of osteoporosis through Wnt signalling.

Open access

Béla Kovács, Lajos Kristóf Kántor, Mircea Dumitru Croitoru, Éva Katalin Kelemen, Mona Obreja, Előd Ernő Nagy, Blanka Székely-Szentmiklósi and Árpád Gyéresi

Abstract

A reverse-phase HPLC (RP-HPLC) method was developed for strontium ranelate using a full factorial, screening experimental design. The analytical procedure was validated according to international guidelines for linearity, selectivity, sensitivity, accuracy and precision. A separate experimental design was used to demonstrate the robustness of the method. Strontium ranelate was eluted at 4.4 minutes and showed no interference with the excipients used in the formulation, at 321 nm. The method is linear in the range of 20–320 μg mL−1 (R2 = 0.99998). Recovery, tested in the range of 40–120 μg mL−1, was found to be 96.1–102.1 %. Intra-day and intermediate precision RSDs ranged from 1.0–1.4 and 1.2–1.4 %, resp. The limit of detection and limit of quantitation were 0.06 and 0.20 μg mL−1, resp. The proposed technique is fast, cost-effective, reliable and reproducible, and is proposed for the routine analysis of strontium ranelate.