ABSTRACT
The aim of this study was to prepare and to investigate acetaminophen taste-masked granules obtained in a high-shear mixer using three different wet granulation methods (method A: water granulation, method B: granulation with a polyvinylpyrrolidone (PVP) binding solution and method C: steam granulation). The studied formulation was: acetaminophen 15%, alpha-lactose monohydrate 30%, cornstarch 45%, polyvinylpyrrolidone K30 5% and orange flavour 5% (w/w). In vitro dissolution studies, performed at pH 6.8, showed that steam granules enabled the lower dissolution rate in comparison to the water and binding solution granules; these results were then confirmed by their lower surface reactivity (D(R)) during the dissolution process. Moreover, the results of the gustatory sensation test performed by six volunteers confirmed the taste-masking effects of the granules, especially steam granules (P<0.001). Morphological, fractal and porosity analysis were then performed to explain the dissolution profiles and the results of the gustatory sensation test. Scanning electron microscopy (SEM) analysis revealed the smoother and the more regular surface of steam granules with respect to the samples obtained using methods A and B; these results were also confirmed by their lower fractal dimension (D(s)) and porosity values. Finally, differential scanning calorimetry (DSC) results showed a shift of the melting point of the drug, which was due to the simple mixing of the components and not to the granulation processes. In conclusion, the steam granulation technique resulted a suitable method to comply the purpose of this work, without modifying the availability of the drug.
Subject(s)
Acetaminophen/chemistry , Drug Compounding/instrumentation , Excipients/chemistry , Taste , Acetaminophen/administration & dosage , Administration, Oral , Calorimetry, Differential Scanning , Drug Stability , Drug Storage , Flavoring Agents/chemistry , Fractals , Humans , In Vitro Techniques , Lactose/chemistry , Particle Size , Pharmaceutic Aids/chemistry , Porosity , Povidone/chemistry , Solubility , Time Factors , Water/chemistryABSTRACT
The aim of this work was to develop a proper mathematical model able to describe the kinetics partitioning of a drug between a polar (water buffer) and an apolar (n-octanol) liquid phase. In particular, attention is focussed on sparingly soluble drugs in one or both environments. Basically, we suppose that drug fluxes occurring between the polar and apolar phase depend also on drug solubility, and not only on both the kinetics constants and the instantaneous drug concentration in the two phases. The proposed model adequately describes the drug partitioning of sparingly water soluble drugs (piroxicam and nimesulide) as proven by the comparison of the predicted and experimental data. Moreover, it indicates the unsuitability of a previous approach (Chem. Pharm. Bull. 29 (1961) 2718) in describing the partitioning kinetics unless sink conditions in both phases are attained, this being difficult to achieve when working with sparingly soluble drugs. Consequently, the model represents a simple and reliable tool to study the drug partitioning kinetics.
