Spray-drying production of trypsin-containing microparticles

This paper describes the production by the spray-drying technique of empty and trypsin-containing Eudragit RL microparticles. The effects of different air drying (heating) temperatures, namely 85, 95, 105 and 135°C, were evaluated. Both empty and trypsin-containing microparticles, characterized by optical and electron microscopy, exhibited the same morphological characteristics. Microparticles demonstrated particle recovery of between 38 and 67% and a size of between 5 and 11 μm. Microparticle recovery, morphological characteristics and mean diameters were not particularly infl uenced by heating. Indeed, in all cases, microparticles maintained a spherical shape, a slight increase in dimensions and no aggregation phenomena. However, an increase in air drying temperature caused a drastic reduction in terms of trypsin activity (assayed by UV determination) with respect to the free enzyme. Indeed, trypsin activity fell from more than 90 to 4.05% in the case of microspheres produced at 95 and 135°C, respectively. Nevertheless, using either suspended or solubilized polymer as the feeding material, the activity profi les of trypsin indicate that the enzyme maintained its activity almost quantitatively (93%) when particles are produced at 95°C. Taken together, these results suggest that spray-drying could represent an interesting technique for the production of microparticles intended for the administration of enzymes

Budesonide microparticles for the treatment of Crohn's disease

none4noneL. Ravani; E. Esposito; E. Menegatti; R. CortesiRavani, Laura; Esposito, Elisabetta; Menegatti, Enea; Cortesi, Rit

ursodeoxycholic acid for oral administration a formulatory study of a suspension

Ursodeoxycholic acid (UDCA), a hydrophilic bile acid effective in dissolving cholesterol gallstones, is usually administered by capsules and tablets. However, oral solid dosage forms are generally inadequate for pediatric needs, since, in order to individualize the preparations, hospitals have to prepare, from capsules, doses corresponding to age and weight of the children. Aim of the present paper was to produce and characterize UDCA suspensions for a personalized regimen of therapy. Four different suspensions were prepared by dissolving preservatives, sodium chloride sweeteners and/or rheology modifiers in hot pure water. After cooling 2.5% (w/v) of UDCA powder was added. After production the formulations were subjected to UDCA content analysis by HPLC, rheological measurements and stability test. The physical and chemical stability of UDCA containing suspensions were investigated for 28 days after production. For physical stability the rate of sedimentation, the height of the sediment and the ease of redispersion, were measured. Particularly, the sedimentation volumes of the four suspensions were between 88 and 95%. The results demonstrated that all UDCA suspensions are characterized by good chemical stability (nominal concentration over 96%). The results indicated that suspensions could be proposed as alternative formulations for the pediatric administration of UDCA

Peptide-based cationic liposomes and micelles as a new tool for nonviral gene delivery

none5This paper describes the synthesis and the physico-chemical characterisation of cationic peptides (CPs) for possible application as non-viral gene delivery systems. Particularly, the production of cationic liposomes and micelle solutions was considered. Five CPs, namely tetralysine cholesteryl hemisuccinate, tetralysine palmitate, tetralysine 3,7-diacetyl-ursodeoxycholate, tetralysine L-aspartic acid b-phosphatidyl-ethanolamine and tetralysine S-farnesyl-L-cysteine were prepared by solid-phase method then isolated, purificated and analitically characterized. Liposomes were prepared by REV-phase and extrusion; micelles were prepared by simple suspension in water of each CP. Afterwards they were characterized by size and charge using a Zetasizer, Malvern, UK. The obtained liposomes present an average diameter reflecting the pore size of the membrane used for the extrusion. After DNA complexation the mean diameter of complexes decreased by increasing the number of positive charges. The non-complexed liposome preparations showed a net positive zeta potential comprised between + 17.8 and + 30 mV. After adding Defibrotide (DFT) to liposomes (at a 1:4 +/- molar ratio) the zeta potential fell down to a net negative value indicating the formation of the ionic complex. Concerning micelles, before complexation it was not possible to measure their size by PCS. However, after DFT complexation the size of complexes highly increased. In addition, before complexation, the five CPs solutions showed a positive zeta potential ranging from +10 to +17.8 mV, while after addition of DFT the zeta potential fells to negative values. Taking into account these results, the studied CPs could be efficiently used to obtain both cationic liposomes and micelles. Moreover they are able to complex DNA with different interaction strength, depending on the type of peptide-based cationic molecule used.noneR. Cortesi; E. Esposito; M. Marastoni; E. Menegatti; C. NastruzziCortesi, Rita; Esposito, Elisabetta; Marastoni, Mauro; Menegatti, Enea; Nastruzzi, Claudi

Different disulfide bridge connectivity drives alternative folds in highly homologous Brassicaceae trypsin inhibitors

Low-molecular-mass trypsin inhibitors from Arabidopsis thaliana, Brassica napus var. oleifera, and Sinapis alba L. (ATTI, RTI, and MTI, respectively) display more than 69% amino acid sequence identity. Among others, the amino acid sequence Cys-Ala-Pro-Arg-Ile building up the inhibitor reactive site, and the eight Cys residues forming four disulfide bridges are conserved. However, the disulfide bridge connectivity of RTI and MTI (C1-C3, C2-C4, C5-C6, and C7-C8) is different from that of ATTI Cys (C1-C8, C2-C5, C3-C6, and C4-C7). Despite the different disulfide bridge connectivity, the reactive site loop of ATTI, RTI, and MTI is solvent exposed permitting trypsin recognition. Structural considerations here reported suggest that proteins showing high amino acid sequence identity and common functional properties could display different three-dimensional structures. This may reflect high inhibitor plasticity in relation to plant-pathogen interactions, plant tissue development as well as the different redox potential of cell compartments

In vitro comparison of four anti-inflammatory topical medications

Measurement of in vitro release and diffusion across a barrier (artificial or biological) of the active ingredient sodium diclofenac from topical products (two originators and the corresponding generics) was carried out. Diclofenac release and availability appeared to be influenced by formulation characteristics, although the observed differences were reduced when skin was used instead of the artificial barrier. The information collected may be useful for the pharmacist when advising patients in the field of anti-inflammatory topical medications

Colloidal dispersions for the delivery of acyclovir: A comparative study

This paper describes a comparative study on the performances of ethosomes and solid lipid nanoparticle as delivery systems for acyclovir. Ethosomes were spontaneously produced by dissolution of phosphatidylcholine and acyclovir in ethanol followed by addition of an aqueous buffer while solid lipid nanoparticle were produced by homogenization and ultrasonication. Both colloidal systems were morphologically characterized by cryo-transmission electron microscopy. The encapsulation efficiency was 94.2±2.8% for ethosomes and 53.2±0.2% for solid lipid nanoparticle. Concerning Z potential, both formulations are close to neutrality. The diffusion coefficients of the drug from ethosomes and solid lipid nanoparticle, determined by a Franz cell method, were 9.4 and 1.2-fold lower as compared to the free acyclovir in solution, thus evidencing the ability of both colloidal systems in enhancing the diffusion of the drug. The antiviral activity against HSV-1 of both systems was tested by plaque reduction assay in monolayer cultures of Vero cells. Data showed that no significant differences in the antiviral activity were observed by acyclovir in the free or loaded forms. Taken together these results, colloidal systems could be interesting to mediate the penetration of acyclovir within Vero cells

Microemulsions of retinoids and pharmaceutical compositions containing them

none5Disclosed are water-in-oil (W/O) microemulsions containing as active ingredient a retinoid, a phospholipid emulsifier, and possibly hyaluronic acid or salts thereof.noneE. MENEGATTI; CORTESI R.; E. ESPOSITO; P. BELLATO; G. GENNARIMenegatti, Enea; Cortesi, Rita; Esposito, Elisabetta; P., Bellato; G., Gennar

LIPOSOME-ASSOCIATED RETINOIDS - PRODUCTION, CHARACTERIZATION AND ANTIPROLIFERATIVE ACTIVITY ON NEOPLASTIC-CELLS

none5This paper describes how the use of different in vitro experimental systems can influence the determination of (a) the drug release profile from microparticles and (b) the interpretation of the release mechanism(s). We employed, as model dosage form, the Parlodel LA, a recently marketed microsphere system especially designed for bromocriptine-controlled delivery. The release kinetics of bromocriptine from microspheres were determined by using two different experimental approaches: a dialysis method and a flow-through cell method. From the comparison of the obtained data it clearly appears that different in vitro experimental models lead to distinct results in terms of drug availability. On the contrary both series of data can be convincingly fitted with the same mathematical equation, giving almost identical results in terms of postulated release mechanism. Taken together these results indicate that different experimental approaches should always be employed to determine drug release kinetics from microparticles in order to obtain more reliable information on the therapeutic dose (bioavailable drug, for in vivo experiments) and on the uniformity of different batches of microspheres.noneR. CORTESI; ESPOSITO E; GAMBARI R; MENEGATTI E; NASTRUZZI CCortesi, Rita; Esposito, Elisabetta; Gambari, Roberto; Menegatti, Enea; Nastruzzi, Claudi