Fluorimetric Analysis of Five Amino Acids in Chocolate: Development and Validation.

Amino acids present ergogenic action, helping to increase, protect, and restore the muscular system of young athletes. Moreover, the encapsulation of five relevant amino acids in chocolate pellet form will appeal to them, facilitating their daily consumption. A reliable HPLC fluorimetric method was developed to detect and quantitatively determine L-Leucine, L-Isoleucine, L-Histidine, L-Valine, and ß-Alanine in chocolate using aniline as an internal standard. Experimental design methodology was used to investigate and optimize the clean-up procedure of the samples. Therefore, three extraction techniques (solid-phase extraction (by two different SPE cartridges) and liquid-solid extraction (LSE)) were compared and evaluated. The LOQ values in chocolate varied from 24 to 118 ng/g (recovery 89.7-95.6%, %RSD < 2.5). Amino acids were pre-column derivatized with o-phthalaldehyde (OPA), while derivatization parameters were thoroughly investigated by experimental design methodology. The analysis was performed by HPLC-fluorescence (emission: λ = 455 nm, excitation: λ = 340 nm) method using a C18 column and a mixture of phosphate buffer (pH = 2.8; 20 mM)-methanol as a mobile phase in gradient elution. The method was validated (r2 > 0.999, %RSD < 2, LOD: 10 ng mL-1 for histidine and leucine, 2 ng mL-1 for alanine and valine, and 4 ng mL-1 for Isoleucine) according to the International Conference on Harmonization guidelines.

Amoxicillin chewable tablets intended for pediatric use: formulation development, stability evaluation and taste assessment.

To cover the unpleasant taste of amoxicillin (250 mg), maize starch (baby food) and milk chocolate were co-formulated. The raw materials and the final formulations were characterized by means of Dynamic Light Scattering (DLS), Differential Scanning Calorimetry (DSC) and Fourier-Transform Infrared (FT-IR) spectroscopy. To evaluate the taste masking two different groups of volunteers were used, according to the Ethical Research Committee of the Aristotle University of Thessaloniki. The optimization of excipients' content in the tablet was determined by experimental design methodology (crossed D-optimal). Due to the matrix complexity, amoxicillin was extracted using liquid extraction and analyzed isocratically by HPLC. The developed chromatographic method was validated (%Recovery 98.7-101.3, %RSD = 1.3, LOD and LOQ 0.15 and 0.45 µg mL-1 respectively) according to the International Conference on Harmonization (ICH) guidelines. The physicochemical properties of the tablets were also examined demonstrating satisfactory quality characteristics (diameter: 15 mm, thickness: 6 mm, hardness <98 Newton, loss of mass <1.0%, disintegration time ∼25min). Additionally, dissolution (%Recovery >90) and in vitro digestion tests (%Recovery >95) were carried out. Stability experiments indicated that amoxicillin is stable in the prepared formulations for at least one year (%Recovery <91).

Solid Dosage Forms of Dexamethasone Sodium Phosphate Intended for Pediatric Use: Formulation and Stability Studies.

Undesirable taste has always been a key issue for oral dosage forms. The aim of the present study was to co-formulate dexamethasone sodium phosphate (DSP), in common pediatric oral forms, using sweet preserves and/or different types of chocolate as excipients. An array of different kinds of chocolate were co-formulated with DSP and were further characterized by means of dynamic light scattering (DLS), x-ray diffraction (XRD), differential scanning calorimetry (DSC) and Fourier-transform infrared (FT-IR) spectroscopy. For the assay of active pharmaceutical ingredient (API), the chocolate samples were pre-treated by means of liquid extraction and analyzed using an high-performance liquid chromatographic (HPLC) method with a strong anion exchange column and a phosphate buffer (17 mM, pH = 3)/acetonitrile, 50:50 v/v as mobile phase. The developed chromatographic method was validated based on the International Conference on Harmonization (ICH) guidelines (%Mean Recovery = 99.4% and %Relative Standard Deviation, RSD = 0.43%). Furthermore, dissolution and in vitro digestion tests of chocolate formulations were evaluated. The DSP was found to be stable for at least 1 year in prepared preparations.