Angelo Spadaro

Chemical stability and bioavailability of acyclovir coupled to α,β-poly(N-2-hydroxyethyl)-dl-aspartamide

Abstract Acyclovir was modified by acylation of the hydroxyl group in the side chain with succinic anhydride, and the O-succinyla-cyclovir derivative obtained was coupled to α,β-poly(N-2-hydroxyethyl)-dl-aspartamide (PHEA) to give a PHEA-O-succinylacyclovir conjugate. Unlike the free drug, the drug-polymer conjugate is freely water-soluble at room temperature. Chemical stability studies in pH 1.1 buffer solution have shown that linking O-succinylacyclovir to PHEA increases the stability of the free drug even more than the succinic derivative. Bioavailability of acyclovir after oral and intravenous administration of its conjugate with PHEA is higher than following administration of free acyclovir.

Calix[4]arene Decorated with Four Tn Antigen Glycomimetic Units and P3CS Immunoadjuvant : Synthesis, Characterization, and Anticancer Immunological Evaluation

A novel anticancer vaccine candidate built on a nonpeptidic scaffold has been synthesized. Four S-Tn tumor-associated glycomimetic antigens have been clustered onto a calix[4]arene scaffold bearing an immunoadjuvant moiety (P3CS). The immunogenicity of the synthetic construct has been investigated by immunization of mice in vivo. ELISA assay has evidenced that the tetravalent construct stimulates a higher production of anti-Tn antigen IgG antibodies when compared to an analogous monovalent compound. This result is ascribable to an antigen cluster effect and makes the reported vaccine candidate a good mimic of the natural motifs present on the mucine surface.

Polymeric prodrugs: α,β-poly(N-hydroxyethyl)-dl-aspartamide as a macromolecular carrier for some non-steroidal anti-inflammatory agents

Abstract The properties as a drug carrier of the biodegradable polymer, α,β- poly (N- hydroxyethyl )- dl - aspartamide (PHEA) were investigated. Thus, naproxen- and 4-biphenylacetic acid-PHEA adducts were prepared and characterized; drug content was evaluated by both UV and elemental analysis and hydrolysis of the adducts. In vivo analgesic and anti-inflammatory tests indicated that the adducts retain an activity comparable to that of the free drugs.

Analysis of aliphatic amines in air samples by HPLC with electrochemical detection.

A method was developed for the analysis of primary aliphatic amines by high performance liquid chromatography coupled with electrochemical detector. The electrochemical oxidation of aliphatic amines derivatized with 2,5-dihydroxybenzaldehyde was investigated at porous graphite electrodes. The derivatization reactions were performed off-line, before the chromatographic separation. The compounds were separated on a reversed phase column with a methanol-acetonitrile-phosphate buffer and detected setting at an oxidation potential of +0.5 V. The influence of the mobile phase buffer concentration and pH on the detector response was also studied. The derivatization was shown to be quantitative and the response linear between 50 and 200 ng/ml. The method is sensitive, selective and could be applicable for the assay of volatile amines in the field of environmental toxicology and also for biological monitoring after occupational exposure.

Synthesis and Immunostimulating Activity of A Thioglycolipopeptide Glycomimetic As A Potential Anticancer Vaccine Derived From Tn Antigen

ABSTRACT The Tn epitope is one of the tumor associated O-linked cell surface glycopeptides. It is expressed in over 70% of human epithelial cancers such as lung, colon, stomach and breast carcinomas. The glycosidic linkage of the Tn antigen, between N-acetylgalactosamine and serine or threonine, can be cleaved either chemically or enzymatically in the presence of glycosidases. The latter case is particularly a problem in vivo. Therefore, it would be of great interest to obtain a metabolically stable analogue of the Tn antigen that maintains or improves the immunogenic activity of the latter. The purpose of this work was to synthesize a totally synthetic vaccine using a chemically and metabolically stable glycomimetic of the Tn antigen in which the interglycosidic oxygen was replaced by a sulphur atom (S-Tn). The S-Tn thioglycopeptide was linked to the P3CS immunoadjuvant to obtain the potential S-Tn vaccine. Moreover, we synthesized the natural Tn antigen and derivatized it similarly to obtain the Tn vaccine. Last, we evaluated the immunostimulating activity of the two synthetic potential vaccines in vitro using cultured mouse splenocytes. The S-Tn construct showed immunostimulating activity comparable, in terms of maximal response, to the Tn analogue. Moreover, due to its higher stability the S-Tn construct reached its maximal effect at lower doses compared to the Tn analogue.

First Self-Adjuvant Multicomponent Potential Vaccine Candidates by Tethering of Four or Eight MUC1 Antigenic Immunodominant PDTRP Units on a Calixarene Platform: Synthesis and Biological Evaluation

MUC1 protein overexpressed in human epithelial carcinoma is a target in development of novel anticancer vaccines. Multiple units of immunodominant B-cell epitope PDTRP MUC1 core sequence were conjugated to calix[4,8]arene platforms containing TLR2 ligand, to produce two novel anticancer self-adjuvant vaccine candidates. The immunogenicity of the synthetic constructs was investigated by immunization of mice in vivo. ELISA assay evidenced that the vaccine candidates stimulate anti MUC1 IgG antibody production (major for the octavalent construct) and no additive effect but a multivalency effect was observed when compared to an analogous monovalent. Octa- and tetravalent constructs lacking in PDTRP peptide moieties did not show anti MUC1 IgG antibody production in mice. The antibodies induced by the synthesized constructs are able to recognize the MUC1 structures present on MCF7 tumor cells. The results display that calixarenes are convenient platforms for building multicomponent self-adjuvant vaccine constructs promising as immunotherapeutic anticancer agents.

4-Quinazolinones: synthesis and reduction of prostaglandin E2 production

We synthesized and evaluated the anti-inflammatory activity of a series of 4-quinazolinone derivatives. Two approaches were used to yield the title compounds. A first group of quinazolinone derivatives was obtained by the appropriate substituted anthranilates. A second group of quinazolinone compounds was prepared through the benzoxazin-4-ones intermediate. The pharmacological results reveal that the synthesized derivatives exhibit a significant anti-inflammatory effect in an experimental ocular inflammation model. In fact, all the tested compounds lowered the prostaglandin E2 (PGE2) production with respect to the control group (P < 0.05). The 3-cyclohexyl-6-chloro-quinazolin-4(3H)-one and 3-cyclohexyl-quinazolin-4(3H)-one derivatives were the most active compounds. These compounds significantly reduced PGE2 levels even more than the reference drug tolmetin and significantly lower protein concentration and polymorphonuclear leukocytes number compared to the control group (P < 0.05). Therefore, these compounds may be useful to prevent ocular inflammatory reactions.

Differential Effects of Modified β-Cyclodextrins on Pharmacological Activity and Bioavailability of 4-Biphenylacetic Acid in Rats after Oral Administration

Gastric tolerability, absorption and pharmacological activity of the non‐steroidal anti‐inflammatory drug 4‐biphenylacetic acid (BPAA), as an inclusion complex with β‐cyclodextrin (β‐CyD) or chemically modified β‐CyDs: 2,6‐di‐O‐methyl‐β‐CyD (DM‐β‐CyD), 2,3,6‐tri‐O‐methyl‐β‐CyD (TM‐β‐CyD) and 2‐hydroxypropyl‐β‐CyD (HP‐β‐CyD), were investigated in the rat after oral administration.

Pharmacological Evaluation of a New Timolol/Pilocarpine Formulation

A new formulation (HYA) based on timolol hyaluronate and pilocarpine hyaluronate salts has been shown to improve the bioavailability of the drugs and to extend the duration of their action. Extent of the intraocular pressure lowering effect, duration of action and aqueous bioavailability of timolol and pilocarpine of HYA were compared with a commercial preparation. Ocular hypertension in the rabbit was induced by α-chymotrypsin or by water loading. The hypotensive effect of HYA treatment was significantly greater and longer than that observed in rabbit eyes treated with the commercial preparation both in the normotensive and in the hypertensive animals. Furthermore, we evaluated the miotic response; due to pilocarpine, normotensive rabbits showed a greater miotic response and an extended duration when the eyes were treated with HYA. The new formulation increased the aqueous availability of timolol and pilocarpine compared to the commercial preparation as determined by HPLC. The pharmacodynamic and pharmacokinetic profiles of HYA indicate an increase in efficacy and duration of action along with an increase in bioavailability of timolol and pilocarpine in comparison with the commercial preparation.

Synthesis, physical properties, toxicological studies and bioavailability of L-pyroglutamic and L-glutamic acid esters of paracetamol as potentially useful prodrugs

Paracetamol ester prodrugs with L‐pyroglutamic and L‐glutamic acid, biosynthetic precursors of glutathione, have been synthesized to reduce paracetamol hepatotoxicity and improve bioavailability.