Preparation of Hydrochlorothiazide Nanoparticles for Solubility Enhancement.

Nanoparticles can be considered as a useful tool for improving properties of poorly soluble active ingredients. Hydrochlorothiazide (Class IV of the Biopharmaceutical Classification System) was chosen as a model compound. Antisolvent precipitation-solvent evaporation and emulsion solvent evaporation methods were used for preparation of 18 samples containing hydrochlorothiazide nanoparticles. Water solutions of surfactants sodium dodecyl sulfate, Tween 80 and carboxymethyl dextran were used in mass concentrations of 1%, 3% and 5%. Acetone and dichloromethane were used as solvents of the model compound. The particle size of the prepared samples was measured by dynamic light scattering. The selected sample of hydrochlorothiazide nanoparticles stabilized with carboxymethyl dextran sodium salt with particle size 2.6 nm was characterized additionally by Fourier transform mid-infrared spectroscopy and scanning electron microscopy. It was found that the solubility of this sample was 6.5-fold higher than that of bulk hydrochlorothiazide.

Synthesis and Antimicrobial Evaluation of 1-[(2-Substituted phenyl)carbamoyl]naphthalen-2-yl Carbamates.

Series of thirteen 1-[(2-chlorophenyl)carbamoyl]naphthalen-2-yl carbamates and thirteen 1-[(2-nitrophenyl)carbamoyl]naphthalen-2-yl carbamates with alkyl/cycloalkyl/arylalkyl chains were prepared and characterized. Primary in vitro screening of the synthesized compounds was performed against Staphylococcus aureus, two methicillin-resistant S. aureus strains, Mycobacterium marinum, and M. kansasii. 1-[(2-Chlorophenyl)carbamoyl]naphthalen-2-yl ethylcarbamate and 1-[(2-nitrophenyl)carbamoyl]naphthalen-2-yl ethylcarbamate showed antistaphylococcal (MICs = 42 µM against MRSA) and antimycobacterial (MICs = 21 µM) activity against the tested strains comparable with or higher than that of the standards ampicillin and isoniazid. In the case of bulkier carbamate tails (R > propyl/isopropyl), the activity was similar (MICs ca. 70 µM). Screening of the cytotoxicity of both of the most effective compounds was performed using THP-1 cells, and no significant lethal effect was observed (LD50 >30 µM). The structure-activity relationships are discussed.

In vitro permeation of micronized and nanonized alaptide from semisolid formulations.

This study is focused on in vitro permeation of the original Czech compound, a skin/mucosa tissue regeneration promoter, known under the international nonproprietary name "alaptide," in micronized and nanonized forms. Alaptide showed a great potential for local applications for treatment and/or regeneration of the injured skin. The above mentioned technological modifications influence the permeation of alaptide through artificial or biological membranes, such as PAMPA or skin. The permeation of micronized and nanonized form of alaptide formulated to various semisolid pharmaceutical compositions through full-thickness pig ear skin using a Franz cell has been investigated in detail. In general, it can be concluded that the nanonized alaptide permeated through the skin less than the micronized form; different observations were made for permeation through the PAMPA system, where the micronized form showed lower permeation than the nanonized alaptide.