Gaetano Ragno

Antiproliferative activity against human tumor cell lines and toxicity test on Mediterranean dietary plants.

Sixteen edible plants from Southern Italy were evaluated for their in vitro antiproliferative properties, using the sulforodamine B (SRB) assay, on four human cancer cell lines: breast cancer MCF-7, prostate cancer LNCaP, amelanotic melanoma C32 and renal adenocarcinoma ACHN. After 48 h of incubation the most antiproliferative plant extract was Cynara cardunculus ssp. cardunculus on C32 and ACHN cell lines with IC(50) of 21 and 18 microg/ml, respectively. Mentha aquatica showed a selective antiproliferative activity on breast cancer while significant activity was exerted by Cichorium intybus on melanoma. These species contained the highest amount of phenolics. The acute toxicity of the hydroalcohol extracts from all the plants were evaluated by using the Microtox acute toxicity test. This bacterial test measures the decrease in light emission from the marine luminescent Vibrio fischeri bacteria when exposed to organic extracts. This inhibition test was revealed to be highly sensitive, cost effective and easy to operate, requiring just 15 min to predict the sample toxicity. All the extracts analyzed resulted to give values very less than a limit of 20% value, demonstrating so an irrelevant toxicity for the human health. In contrast, Echium vulgare and Malva sylvestris showed bioluminescence inhibition values of 19.42% and 17.32%, respectively, just under the established limit.

Photodegradation monitoring of amlodipine by derivative spectrophotometry

A derivative spectrophotometric method for the simultaneous determination of amlodipine and its pyridine photodegradation product has been developed. The analytes concentrations were linearly correlated with spectral measurements in the 3rd order UV derivative spectrum through equations obtained by simple and multiple regression analysis. The recovery values were estimated to range from 95 to 99% and the quantitation limit of the photoproduct was found to be equivalent to an impurity level of 1%, with respect to the content of amlodipine. The method could usefully be applied to routine quality control of pharmaceutical formulations containing amlodipine.

Kinetic studies of nitrofurazone photodegradation by multivariate curve resolution applied to UV-spectral data

This work aims at describing the kinetic model of nitrofurazone photodegradation by a novel chemometric technique, hybrid hard-soft multivariate curve resolution (HS-MCR). The study was applied to UV-spectral data from the photolysis of nitrofurazone solutions at different concentrations and exposed under varying illuminance power. The HS-MCR method was able to elucidate the kinetics of the photodegradation process and to determine the rate constants, and estimating at the same time the pure spectra of the degradation products. Exposure to light of the drug gave a first rapid isomerization to the syn-form that in turn underwent degradation furnishing a mixture of yellow-red products. The photodegradation process could be explained with a kinetic model based on three consecutive first-order reactions (A>B, B>C and C>D). These results were confirmed by application of the MCR procedure to the analysis of the data obtained from HPLC-DAD analysis of the nitrofurazone samples at different reaction times. The kinetic model was observed to be dependent on experimental conditions. The samples at higher concentrations showed rate constants lower than the diluted samples, whereas an increase of the rate of all degradation processes was observed when the light power also increased. This work shows the power of the hybrid hard- and soft-multivariate curve resolution as a method to deeply study degradation processes of photolabile drugs.

Multivariate analysis of paracetamol, propiphenazone, caffeine and thiamine in quaternary mixtures by PCR, PLS and ANN calibrations applied on wavelet transform data.

The quantitative resolution of a quaternary pharmaceutical mixture consisting of paracetamol, propiphenazone, caffeine and thiamine was performed by the simultaneous use of fractional wavelet transform (FWT) with principal component regression (PCR), partial least squares (PLS) and artificial neural networks (ANN) methods. A calibration set consisting of 22 mixture solutions was prepared by means of an orthogonal experimental design and their absorption spectra were recorded in the spectral range of 210.0-312.3nm and then transferred into the fractional wavelet domain and processed by FWT. The chemometric calibrations FWT-PCR, FWT-PLS and FWT-ANN were computed by using the relationship between the coefficients provided by FWT method and the concentration data from calibration set. An external validation was carried out by applying the developed methods to the analysis of synthetic mixtures of the related compounds, obtaining successful results. The models were finally used to assay the studied drugs in the commercial pharmaceutical formulations.

Progesterone administration by nasal spray

The bioavailability and the clinical usefulness of the P administered by nasal spray were investigated. Ten healthy menopausal women received an IN spray administration (4 doses of an oleic P solution 20 mg/mL, corresponding to nearly 11.2 mg of P) and the circulating P levels were calculated. Sixty minutes after administration, the maximum concentration (CMax, 3.75 +/- 0.214 ng/mL) was reached. High P levels (greater than 2 ng/mL) lasted until 360 minutes, and the AUC 0 to 720 was 1,481.6 +/- 343 ng.h/mL. Progesterone administration by spray formulation has proven to be effective in reaching therapeutic levels and to be acceptable to patients and, probably, clinically safe.

Prediction of photosensitivity of 1,4-dihydropyridine antihypertensives by quantitative structure-property relationship

A quantitative structure-property relationships (QSPR) model, correlating the light sensitivity against theoretical molecular descriptors, was developed for a set of 1,4-dihydropyridine calcium channel antagonist drugs. These compounds are characterized by a high tendency to degradation when exposed to light, furnishing in the most of cases a related oxidation product from aromatization of the dihydropyridinic ring. Photodegradation was forced by exposing the drugs to a Xenon lamp, in accordance with the ICH international rules, and degradation kinetics was monitored by spectrophotometry. The photodegradation rates combined with a series of descriptors related to the chemical structures were computed by Partial Least Squares (PLS) multivariate analysis. An accurate selection of the variables, fitting at the best the PLS model, was performed. Two descriptors related to the substituent information on both the dihydropyridinic and benzenic rings and four molecular descriptors, were selected. The QSPR model was fully cross validated and then optimized with an external set of novel 1,4-dihydropyridine drugs, obtaining very satisfactory statistical results. The good agreement between predicted and measured photodegradation rate (R(2)=0.8727) demonstrated the high accuracy of the QSPR model in predicting the photosensitivity of the drugs belonging to this class. The model was finally proposed as an effective tool to design new congeneric molecules characterized by high photostability.

Nasally-administered progesterone: comparison of ointment and spray formulations

The aim of the study was to compare the bioavailability and clinical usefulness of progesterone (P) administered nasally in spray or ointment form. Twenty healthy post-menopausal women were randomly allocated to treatment by either intranasal spray (4 doses of an oil-based P solution at a concentration of 2 mg/0.1 ml, corresponding to a total dose of approximately 11 mg of P) or an ointment (quantity 0.1 ml, P concentration 20 mg/0.1 ml). Circulating P levels were calculated at various time intervals following administration. The spray formulation yielded a mean maximum concentration (CMax) of 3.75 ng/ml after 60 min (TMax) and the area under the curve (AUC) 0-720 min was 1481.6 +/- 343 ng.h/ml. The ointment yielded a mean CMax of 1.19 ng/ml at TMax = 30 min, the AUC 0-720 value being 404.35 +/- 148 ng.h/ml. The study findings confirmed that the intranasal route is a potentially useful alternative for the administration of natural sex steroid hormones, making it possible to avoid first-pass liver metabolism. P administered by spray showed greater bioavailability than it did when administered in ointment form, while both formulations seemed to be acceptable to patients and were probably clinically safe.

Photostability of barnidipine in combined cyclodextrin-in-liposome matrices

BACKGROUND The improvement of barnidipine photostability was investigated in cyclodextrin or liposome matrices and in appropriate combinations of these matrices. These supramolecular systems allowed the preparation of liquid formulations, as an alternative to the current solid commercial specialties. MATERIALS & METHODS Photodegradation stressing tests were performed according to the ICH rules and monitored by derivative spectrophotometry. Optimization was evaluated in terms of drug-inclusion efficiency. RESULTS The photodegradation rate of barnidipine in ethanol proved rapid (residual percentage of 29.81%) after a radiation exposure of 225 kJ/m(2). The residual concentrations detected for liposome and cyclodextrin complexes were 42.90 and 72.03%, respectively. The best results were obtained when the drug-cyclodextrin complex was in turn entrapped in liposomes (residual percentage of 90.78%). CONCLUSION The stability of the drug-in-cyclodextrin-in-liposome system increased significantly with a value close to that of solid formulations whose residual percentage was 96.03%.

Analysis of nimodipine and its photodegradation product by derivative spectrophotometry and gas chromatography

Abstract A derivative spectrophotometric method for the simultaneous determination of nimodipine and its major degradation product in commercial pharmaceutical forms is proposed. The method has been defined on synthetic mixtures and compared with a new gas chromatographic procedure, as a reference method. The UV method has been used to study drug photodegradation in commercial specialities. Both methods, whose results are statistically compared, show satisfactory values of accuracy and reproducibility.

Study of photodegradation kinetics of melatonin by multivariate curve resolution (MCR) with estimation of feasible band boundaries.

Multivariate curve resolution-alternating least squares (MCR-ALS) has been applied to data collected from UV spectrophotometric analysis of melatonin samples exposed to light with varying irradiance power. MCR-ALS was able to explain the degradation kinetics of this drug, deducing the pure spectra and concentration changes of the different species present throughout the entire process. Possible rotational ambiguities associated with MCR solutions were investigated and their extent was evaluated. The extent of the rotation ambiguity was estimated from the band boundaries of feasible solutions calculated using the MCR-BANDS procedure. The use of a non-linear fitting routine allowed improving kinetic information and provided a method of evaluation of the rate constants of the degradation process. The degradation pathway was found to follow a first-order reaction model, in which melatonin underwent photo-oxidation of the indole ring to give a formylamine group. Kinetics of the reaction was shown to be dependent on irradiation conditions, with an increase of the rate constants when light power also increased.