Biomedical subjects

A Manderioli

Publications and source records attributed to A Manderioli.

5 recordsLinked to original sources

PubMed1999

Influence of the preparation method on the physicochemical properties of binary systems of econazole with cyclodextrins.

Equimolar combinations of econazole, a very poorly water soluble antifungal agent, with beta-cyclodextrin and statistically substituted methyl-beta-cyclodextrin were investigated for both solid state characterization (differential scanning calorimetry, hot-stage microscopy, infrared spectroscopy, scanning electron microscopy) and dissolution properties (dispersed amount method). The influence of the preparation method (physical mixing, ball-milling, kneading, sealed-heating) on the physicochemical properties of the products was evaluated. Kneading and sealed-heating techniques led to amorphous products in the case of systems with methyl-beta-cyclodextrin, whereas crystalline drug was still clearly detectable in all products with beta-cyclodextrin. Independently of the preparation technique, all combinations with methyl-beta-cyclodextrin yielded better performance than the corresponding ones with beta-cyclodextrin. However, the influence of the preparation method was clearly more marked for products with methyl-beta-cyclodextrin and made to be possible to better display the different performance of the examined carriers. In fact, the sealed-heated with the beta-derivative showed an increase of drug dissolution efficiency of 130% with respect to the corresponding physical mixture, in comparison to the 70% increase obtained from that with beta-cyclodextrin. Moreover, whereas the difference in dissolution efficiency values between coground products was only about 8% in favor of the beta-derivative, it reached 80 and 90% between sealed-heated and kneaded products, respectively.

Antifungal Agents↗

PubMed1999

Thermal behavior and dissolution properties of naproxen from binary and ternary solid dispersions.

Solid dispersions of 10% w/w naproxen (NAP) in poly(ethylene glycol) (PEG) (4000, 6000, or 20,000) as a carrier with or without incorporation of anionic (sodium dodecyl sulfate; SDS) or nonionic (Tween 80; Tw80) surfactant were prepared by the melting method. Physicochemical characteristics were determined by differential scanning calorimetry (DSC) and X-ray diffraction analysis. The results of dissolution studies showed that drug dissolution properties were better from ternary systems than from binary systems since in the former the wetting and solubilizing effects of surfactant and polymer were additive. No influence of the PEG molecular weight was found. The best performance given by anionic surfactant has been attributed to several factors, such as higher hydrophilicity, better solubilizing power, and most facile interaction with both drug and PEG. No important changes in solid-state characteristics or in drug dissolution properties were found after 30 months storage for dispersions with or without surfactant. Only a slight decrease in initial drug dissolution rate was observed at the highest concentration (10% w/w) of SDS.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1998

Compatibility study between ibuproxam and pharmaceutical excipients using differential scanning calorimetry, hot-stage microscopy and scanning electron microscopy.

Differential scanning calorimetry (DSC) was used as a screening technique for assessing the compatibility of ibuproxam with some currently employed pharmaceutical excipients. The influence of processing effects (simple blending, cogrinding or kneading) on drug stability was also evaluated. On the basis of DSC results, ibuproxam was found to be compatible with corn starch, avicel and sodium carboxymethylcellulose. Some drug-excipient interaction was observed with polyethyleneglycol 4000, palmitic acid, stearic acid, Ca and Mg stearate. Actual solid-phase interactions of the drug with polyvinylpolypyrrolidone and polyvinylpirrolidone K30 were induced by mechanical treatments. Hot-stage microscopy (HSM) and scanning electron microscopy (SEM) were of help in interpreting the DSC results and excluding in all cases relevant pharmaceutical incompatibilities.

Benzeneacetamides↗

PubMed1998

Thermal analysis as a screening technique in preformulation studies of picotamide solid dosage forms.

The potential compatibilities of several commonly used pharmaceutical excipients with picotamide were evaluated using differential scanning calorimetry (DSC). The effects of aging and of mechanical treatment (blending, grinding, or kneading) of samples were also evaluated. Hot-stage microscopy (HSM) and scanning electron microscopy (SEM) were used as complementary techniques to implement and assist in interpretation of the DSC results. DSC analysis evidenced a noticeable modification of drug thermal features in the mixtures with palmitic acid, stearic acid, stearyl alcohol, polyethylene glycol (PEG) 20,000, and sorbitol, but HSM analysis showed that the DSC behavior was mainly because of the drug dissolution in the melted excipient, which allowed the presence of important solid-solid interactions to be excluded. Compatibility with Mg stearate was also found, even if sample manipulation induced the partial conversion of Mg stearate in a pseudo-polymorphic modification. Mechanical stress displayed an increased hygroscopicity of mixtures with glucose and lactose, as well as some solid-solid interactions with lactose and mannitol.

Calorimetry, Differential Scanning↗

PubMed1996

Influence of vehicle composition variations on the in vitro and ex vivo clonazepam diffusion from hydrophilic ointment bases.

A systematic study of formulation factors influencing the release of clonazepam from hydrophilic ointment bases was performed. Diffusion experiments were carried out using both artificial membranes (cellulose nitrate membrane impregnated with lauryl alcohol or isopropylmiristate or vaseline oil) and natural ones (rabbit ear skin). The formulation variables were the percentage of polyethylene glycol 400, polyethylene glycol 6000 and water, and the type of lipophilic component (lauryl alcohol, isopropylmyristate or vaseline oil) added to the vehicle. In vitro and ex vivo results were compared and the best formulation was found, even if it was not possible to establish a precise correlation between the in vitro and ex vivo flux values.

Animals↗