Volume 61 (2011): Issue 1 (March 2011)

In the last few years, various studies have been providing evidence that metal ions are critically involved in the pathogenesis of major neurological diseases (Alzheimer, Parkinson). Metal ion chelators have been suggested as potential therapies for diseases involving metal ion imbalance. Neurodegeneration is an excellent target for exploiting the metal chelator approach to therapeutics. In contrast to the direct chelation approach in metal ion overload disorders, in neurodegeneration the goal seems to be a better and subtle modulation of metal ion homeostasis, aimed at restoring ionic balance. Thus, moderate chelators able to coordinate deleterious metals without disturbing metal homeostasis are needed. To date, several chelating agents have been investigated for their potential to treat neurodegeneration, and a series of 8-hydroxyquinoline analogues showed the greatest potential for the treatment of neurodegenerative diseases.

Pharmaceutical production and distribution constitute big business. For the companies the rewards can be substantial. Rates of return on drug company investments tend to be higher than many other manufacturing enterprises. But reward is only one side of the story. There is also the issue of social risk, the focus of this article. Social risk for pharmaceutical production is especially pronounced. An ineffective or, worse, dangerous drug, can have dire consequences for the population at large. For this reason, there is elaborate government regulation and oversight of drug safety and risk. These systems, especially in the US and Europe, will be the main focus of this paper. The two systems will be described, and then compared and contrasted in terms of their framing of social risk and actions governments take to limit it. Systems elsewhere, especially in the developing world, are increasing in relative importance and these will be briefly discussed as well. Ethical issues that have arisen in these various systems will be surfaced and analysed. The paper will close with some conclusions and suggestions for further research.

The present study deals with the development of hydroxyapatite (HAp)-ciprofloxacin bone-implants using the »Quality by design« approach. The effect of various synthesis parameters like drug amount added in the process, stirring speed and addition rate of orthophosphoric acid in the synthesis on drug concentration in the HAp-ciprofloxacin system synthesized by the precipitation technique using 2³ factorial design was analyzed. Optimization methodology utillizing the first-order polynomial equation was used to search for optimal drug concentration in the HAp-ciprofloxacin implant system. The observed responses coincided well with the predicted values from the optimization technique. New implants were manufactured using various HAp-ciprofloxacin composites and 1.5 % (m/V) guar gum as a binder. Characterization of the delivery system was done by XRPD, FTIR spectroscopy and SEM. Even at highest drug concentration (76.6 ± 0.5 %, m/m), ciprofloxacin was present in noncrystalline state. The in vitro ciprofloxacin release from various bone-implants was sustained for several weeks and the drug release pattern correlated well with the Korsmeyer- Peppas model.

Simultaneous determination of valsartan and hydrochlorothiazide by the H-point standard additions method (HPSAM) and partial least squares (PLS) calibration is described. Absorbances at a pair of wavelengths, 216 and 228 nm, were monitored with the addition of standard solutions of valsartan. Results of applying HPSAM showed that valsartan and hydrochlorothiazide can be determined simultaneously at concentration ratios varying from 20:1 to 1:15 in a mixed sample. The proposed PLS method does not require chemical separation and spectral graphical procedures for quantitative resolution of mixtures containing the titled compounds. The calibration model was based on absorption spectra in the 200-350 nm range for 25 different mixtures of valsartan and hydrochlorothiazide. Calibration matrices contained 0.5-3 μg mL^-1 of both valsartan and hydrochlorothiazide. The standard error of prediction (SEP) for valsartan and hydrochlorothiazide was 0.020 and 0.038 μg mL^-1, respectively. Both proposed methods were successfully applied to the determination of valsartan and hydrochlorothiazide in several synthetic and real matrix samples.

The aim of the work was to synthesize heterocyclic compounds from 2-aminoprop-1-ene-1,1,3-tricarbonitrile and to study their antitumor activities. The title reagent reacted with cyclohexanone to give the ethylidene derivative 2. The reactivity of the latter product towards different chemical reagents was studied to give tetrahydronaphthalene, hexahydroisoquinoline and hexahydrocinnoline derivatives. The newly synthesized products were screened as antitumor agents on the in vitro growth of three human tumor cell lines representing different tumor types, namely, breast adenocarcinoma (MCF-7), non-small cell lung cancer (NCI-H460) and CNS cancer (SF-268). It was found that some of these compounds showed inhibitory effects on the three cell lines, indicating their potential use in the development of oncology products.

Cisplatin-loaded protransfersome system was prepared and characterized for in vitro drug permeation, drug deposition and antitumor effect. A histopathological study and a genotoxicity study were also done. The skin permeation data of cisplatin from protransfersome gel formulation revealed 494.33 ± 11.87 μg cm^-2, which was significantly higher than that from the control plain drug solution in 0.9 % NaCl (p < 0.001). Untreated group of animals showed invasive moderately differentiated keratinizing squamous cell carcinoma (malignant stage). However, with cisplatin loaded protransfersome gel system simple epithelial hyperplasia (pre-cancerous stage) with no cancerous growth was observed. Also, a significant induction in micronucleus formation was found in the group that was treated with injectable intraperitoneal cisplatin preparation in 0.9 % saline as compared to the group treated with topical protransfersome gel formulation. The findings of this research work appear to support improved, site-specific and localized drug action in the skin, thus providing a better option for dealing with skin related problems like squamous cell carcinoma.

In situ forming intragastric controlled-release formulation is a new technology in the field of oral controlled-release delivery systems. The objective of this study was to develop formulations that can control drug release up to 24 hours. In addition, a combination of appropriate polymers and solvents was selected that could form a drug loaded gel at the process temperature of 60-70 °C, which gel could turn into a rigid mass upon exposure to dissolution fluid at body temperature. The drug release mechanism from this rigid mass was controlled by different formulation factors such as different polymer grades, polymer concentrations, hydrophobicity or hydrophilicity of solvents, different drug loadings, and physicochemical properties of additional excipients. After evaluating different formulation factors, Ethocel 10 FP and triethyl citrate were selected for further studies using hydrochlorothiazide as a model drug. Polynomial correlation between viscosity of the blank gel and drug release profile was also obtained.

The aim of this study was to prepare fast-dissolving tablets of meloxicam after its complexation with β-cyclodextrin (β-CD) and to investigate the effect of using different superdisintegrants on the disintegration and release of meloxicam from the tablets. A complex of meloxicam with β-CD was prepared by spray drying and then compressed in the form of tablets utilizing the direct compression technique. Three superdisintegrants were employed at various levels - sodium starch glycolate, croscarmellose sodium, and crospovidone. Co-spray dried micro-crystalline cellulose and mannitol (Avicel HFE-102) were used as diluents in the tablets. Prior to compression, the pre-compression parameters showed satisfactory flow properties. Post-compression parameters showed that all tablet formulations had acceptable mechanical properties. Wetting and disintegration times were prolonged by increasing the level of sodium starch glycolate in the tablets. This was attributed to the formation of a viscous gel layer around the tablets by sodium starch glycolate whereas this effect was not observed with croscarmellose sodium and crospovidone. Dissolution studies showed fast release of meloxicam except in tablets containing a high level of sodium starch glycolate. Complexation of meloxicam with β-CD significantly improved the solubility of the drug and improved the mechanical properties of tablets produced by direct compression.

A new and simple flame atomic-absorption spectrometric (FAAS) method is proposed for simultaneous determination of iron and copper in children's sera. It is based on single-step sample pretreatment (deproteinization with 3 mol L^-1 HCl, ratio 1:1) and single-step calibration using 1.5 mol L^-1 HCl standard. During method's optimization a short multifactorial design experiment was used. The proposed method assures accuracy, sensitivity and precision comparable to that of the reference methods. The new approach is simple and time-, labour- and serum-saving, the latter being especially important in pediatric diagnostics.

The series of 6,7,8,9-tetrahydro-5H-5-(2'-hydroxyphenyl)-2-(4'-substituted benzylidine)thiazolo(2,3-b)quinazolin-3(2H)-ones (4a-j) and 6,7,8,9-tetrahydro-5H-5-(2'-hydroxyphenyl)-2-(4'-substituted benzylidine)-3-(4-nitrophenyl amino)thiazoloquinazolines (5a-j) were synthesized by the reported method and evaluated for their phosphodiesterase inhibitory activity. All test compounds exhibited good activity. The structure-activity relationships were also studied. In both series of compounds, electron-withdrawing substitutions showed higher activity. Among the tested compounds, 6,7,8,9-tetrahydro-5H-5-(2'-hydroxyphenyl)-2-(4'-fluorobenzylidine)-3-(4-nitrophenylamino)thiazoloquinazoline (5e), 6,7,8,9-tetrahydro-5H-5-(2'-hydroxyphenyl)-2-(4'-nitrobenzylidine)-3-(4-nitrophenylamino)thiazoloquinazoline (5j) and 6,7,8,9-tetrahydro-5H-5-(2'-hydroxyphenyl)-2-(4'-chlorobenzylidine)-3-(4-nitrophenylamino)thiazoloquinazoline (5f) were found to be more potent than theophylline (IC₅₀ in mmol L^-1 of 1.34 ± 0.09 for 5f, 1.44 ± 0.02 for 5e, 1.52 ± 0.05 for 5jvs. 1.72 ± 0.09 for theophylline).