Sofía Negro

Poly (D,L-lactide-co-glycolide) microspheres for long-term intravitreal delivery of aciclovir: Influence of fatty and non-fatty additives

Aciclovir (acicloguanosine) has been demonstrated to be effective in the treatment of intraocular pathologies such as herpes simplex virus retinitis and acute retinal necrosis. Although intravitreal injections have been used with fewer side-effects than intravenous administration, the risk of complications increases with the frequency of intravitreous injections. For this reason, a biodegradable drug-delivery system, such as microspheres, able to promote prolonged release of the drug, offers a good alternative to multiple intraocular administrations. In this work, aciclovir-containing poly (D,L-lactide-co-glycolide) microspheres were prepared by the solvent evaporation method. Seven additives were incorporated in the microspheres to modulate the in vitro release rate of the drug: four non-fatty substances (polyethylene glycol 300, polyethylene glycol 1500, hydroxypropyl methylcellulose and gelatin) and three fatty substances (isopropyl myristate, vitamin E and Labrafil M 1944 CS). Morphology of microspheres was evaluated by scanning electron microscopy. Granulometric analysis showed that particle size distribution was significantly influenced by the incorporation of additives. Loading efficiency decreased when fatty substances were added, whereas non-fatty additives promoted higher incorporation of the drug. Infrared and differential scanning calorimetry analyses indicated that microspheres prepared by the solvent evaporation process were not influenced by the type of additive used. In all cases, the initial burst resulted less than 5%. Additive-free microspheres showed a slow release within the first days, but when additives were incorporated, in general, the release rates of the drug were increased. Best release results were obtained for gelatin-containing microspheres. The release of aciclovir from these microspheres was adjusted to a zero-order kinetic from 1 to 49 days with a release constant of 1.13 microg/day/mg microspheres. A dose of 0.74 mg microspheres would be therapeutic for the herpes simplex and Epstein-Barr viruses (MIC 0.1 microg/ml) and 7.4 mg for varicella zoster virus (MIC 1 microg/ml) treatment in an animal model.

An effective novel delivery strategy of rasagiline for Parkinson's disease.

This is the first report on the efficacy of a new controlled release system developed for rasagiline mesylate (RM) in a rotenone-induced rat model of Parkinsons disease (PD). PLGA microspheres in vitro released RM at a constant rate of 62.3 μg/day for two weeks. Intraperitoneal injection of rotenone (2 mg/kg/day) to Wistar rats produced typical PD symptoms. Catalepsy, akinesia and swim tests outcomes in animals receiving RM either in solution or within microspheres showed a reversal in descent latency when compared to rotenone-treated animals, being this reversal specially pronounced in animals receiving RM microspheres (dose equivalent to 1 mg/kg/day RM injected i.p. every 15 days). Nissl-staining of brain sections showed selective degeneration of the substantia nigra (SNc) dopaminergic neurons in rotenone-treated animals which was markedly reverted by RM microspheres. PET/CT with (18)F-DG resulted in mean increases of accumulation of radiotracer in striatum and SNc of around 40% in animals treated with RM microspheres which also had significant beneficial effects on Bcl-2, Bax, TNF-α mRNA and SOD2 levels as detected by real-time RT-PCR. Our results confirm the robust effect achieved by the new controlled release system developed for RM which exhibited better in vivo efficacy than RM given in solution.

Development and validation of a reverse phase liquid chromatography method for the quantification of rasagiline mesylate in biodegradable PLGA microspheres

In the present study, a reverse phase high performance liquid chromatographic method was developed and validated for the determination of rasagiline mesylate in biodegradable microspheres. Chromatographic separation was carried out on a RP-18 column using a mobile phase consisting of acetonitrile:water (5:95, v/v) adjusted at pH 3.1. Flow rate was 1.0 ml min(-1) and UV detection at 290 nm. Acyclovir was used as the internal standard. The calibration curve was linear over the range 0.5-20.0 microg ml(-1). R.S.D. for precision was <1.8%. Accuracy ranged between 99.01% and 102.55% with a R.S.D. lower than 1.3%. LOD and LOQ were 0.07 microg ml(-1) and 0.23 microg ml(-1), respectively. The method was simple, rapid, and easy to apply, making it very suitable for routine analysis of rasagiline mesylate in biodegradable PLGA microspheres. It could be also used with reliability for the determination of the drug in other pharmaceutical dosage forms.

Controlled release of rasagiline mesylate promotes neuroprotection in a rotenone-induced advanced model of Parkinson's disease

Microencapsulation of rasagiline mesylate (RM) into PLGA microspheres was performed by method A (O/W emulsion) and method B (W/O/W double emulsion). The best formulation regarding process yield, encapsulation efficiency and in vitro drug release was that prepared with method A, which exhibited constant drug release for two weeks (K(0)=62.3 μg/day/20mg microspheres). Exposure of SKN-AS cells to peroxide-induced oxidative stress (1 mM) resulted in cell apoptosis which was significantly reduced by RM (40.7-102.5 μM) as determined by cell viability, ROS production and DNA fragmentation. Daily doses of rotenone (2 mg/kg) given i.p. to rats for 45 days induced neuronal and behavioral changes similar to those occurring in PD. Once an advanced stage of PD was achieved, animals received RM in saline (1 mg/kg/day) or encapsulated within PLGA microspheres (amount of microspheres equivalent to 15 mg/kg RM given on days 15 and 30). After 45 days RM showed a robust effect on all analytical outcomes evaluated with non-statistically significant differences found between its administration in solution or within microparticles however; with this controlled release system administration of RM could be performed every two weeks thereby making this new therapeutic system an interesting approach for the treatment of PD.

Effective antiproliferative effect of meloxicam on prostate cancer cells: Development of a new controlled release system

Recent studies have shown that COX-2 inhibitors, such as meloxicam, have demonstrated promising results when used with chemotherapy. Based on these findings, this is the first study in which the antiproliferative effect of meloxicam is investigated on two prostate cancer cell lines (PC3 and DU-145). We have also evaluated if this antiproliferative effect is dose- and/or time-dependent. Meloxicam is assayed at a concentration range of 10-800 microM for 24, 48 and 72 h. Our results reveal that meloxicam has a selective dose- and time-dependent antiproliferative effect against PC3 but not against DU-145 cells. In PC3 cells the IC(50) decreased from 740 microM at 24 h to 515 microM at 72 h after meloxicam treatment. Chemoembolization based on microspheres has been emerged as a novel and promising way for antitumoural therapy; therefore, in our study we have developed and characterized a new controlled release system consisting of biodegradable PLGA/PEG-derivative meloxicam microspheres. The optimized formulation has a mean particle size of 13.06+/-0.09 microm, mean encapsulation efficiency of 58.44+/-4.53% and releases 0.45+/-0.05 microg meloxicam/day/mg microspheres between days 3 and 28 of the in vitro release assay. In conclusion, we should consider meloxicam as a possible adjuvant agent in the treatment of prostate cancer.

Compatibility and stability of tramadol and dexamethasone in solution and its use in terminally ill patients.

Background:  Delivery of drug admixtures by continuous subcutaneous infusion is common practice in palliative medicine, but analytical confirmation of their compatibility and stability is not always available.

New celecoxib multiparticulate systems to improve glioblastoma treatment.

Treatment of malignant gliomas consists of resection followed by radiotherapy and chemotherapy. Celecoxib (CXB), a selective COX-2 inhibitor, is able to control inflammation and pain, to improve the efficacy of radiotherapy, and to inhibit at high doses the growth of cancer cells. Two new delivery systems for CXB are developed: microspheres (MPs) for implantation in the brain after partial/complete removal of the tumor, and nanoparticles (NPs) for their potential to cross the blood brain barrier and deliver CXB into the CNS. Cell culture assays performed in PC12, SKN-AS and U373-MG cells demonstrate the antiproliferative affects of CXB, with EC50 values of 99.81 μM and 82.4 μM in U373-MG and SKN-AS cells. Encapsulation efficacy of CXB in formulation MP2 (20% CXB) was 74.6 ± 2.2% with a zero-order release rate of 47.8 μg/day/20mg microspheres for 34 days. Uncoated and polysorbate 80-coated CXB-NPs are prepared by nanoprecipitation. Mean sizes of uncoated and coated CXB-NPs were 173.6 ± 44.9 nm and 100.6 ± 62.1 nm. Cerebral cortex images showed a marked increase of fluorescence when the surfactant-coated NPs were administered to rats. These results suggest that both CXB formulations (MPs and NPs) are adequate systems to enhance the effects of chemotherapy in the treatment of malignant brain tumor.

Compatibility and stability of ternary admixtures of tramadol, haloperidol, and hyoscine N-butyl bromide: retrospective clinical evaluation.

BACKGROUND Combination of drugs for subcutaneous infusion is common practice in palliative medicine, however, there is no information pertaining to the compatibility and stability of tramadol combined in ternary admixtures and no information exists regarding its clinical performance. METHODS Tramadol hydrochloride, haloperidol lactate, and hyoscine N-butyl bromide have been examined for compatibility and stability when combined in solution under conditions mimicking their potential use via subcutaneous infusion in terminal oncology patients. Concentration ranges were 8.8-33.3 mg/mL, 0.208-0.624 mg/mL, and 3.33-6.67 mg/mL for tramadol hydrochloride, haloperidol lactate, and hyoscine N-butyl bromide. With these, 27 different admixtures were prepared and stored at 25 degrees C using 0.9% saline as diluent. Quantification was performed by high-performance liquid chromatography (HPLC). The clinical performance of the admixture was retrospectively assessed in 28 terminal oncology patients exhibiting Karnofskys indexes of 10%-20%. RESULTS All three drugs were very stable (>92%) at 25 degrees C for 15 days. Pain was completely controlled in all patients. Fifty percent of the patients suffered from 3-5 vomiting episodes per day and of these, 75% experienced complete control of the episodes. None of the patients showed local reactions after subcutaneous administration of the admixture. RESULTS Our results confirm the compatibility and stability of the ternary admixture and its utility in highly vulnerable patients exhibiting moderate symptoms.

HPLC-UV method development and validation for the quantification of ropinirole in new PLGA multiparticulate systems: Microspheres and nanoparticles

A simple HPLC-UV method was developed and validated for the quantitation of RP free base encapsulated into two new multiparticulate systems (microparticles and nanoparticles), as well as for the quantification of RP hydrochloride when given as a loading dose together with the new delivery system developed. HPLC separation was achieved using a C18 Kromasil column (250 mm × 4 mm) with a mobile phase composed of acetonitrile-phosphate buffer solution (55:45, v/v) adjusted at pH 6.0 and containing 0.3% triethanolamine. Flow rate was set at 1.0 mL min(-1). The UV detector was operated at 245 nm. The method allowed for the simultaneous determination of both RP and RP-HCl. The method was linear within the range 2.5-50 μg mL(-1) for both RP and RP-HCl. The limits of detection (LOD) and quantitation (LOQ) found were 0.8 μg mL(-1) and 2.4 μg mL(-1) for RP, and 0.3 μg mL(-1) and 0.9 μg mL(-1) for RP-HCl. The method was found to be simple, rapid, specific, precise, accurate, and reproducible. The method was successfully applied to the determination of the encapsulation efficiency of RP in the multiparticulate systems developed, being 85.03 ± 3.77% and 51.12 ± 3.50%, for RP-loaded PLGA microspheres and RP-loaded PLGA nanoparticles, respectively.

Protective effects of clioquinol on human neuronal-like cells: a new formulation of clioquinol-loaded PLGA microspheres for Alzheimer’s disease

Background: Clioquinol (CQ), a metal chelator, has gained renewed attention due to its ability to modulate metal homeostasis in neurodegenerative disorders such as Alzheimer’s disease. Purpose: To investigate the protective effects of a wide range of concentrations of CQ on two human neuroblastoma cell lines (IMR-32 and SKN-AS) and to develop and characterize a new controlled release system of CQ consisting of biodegradable microspheres. Results: H2O2 (400 μM) adequately induced death cell in IMR-32 and SKN-AS cell lines thereby resulting in a useful model for neuroprotective studies. CQ (20–50 μM) induced a potent and robust protective effect against peroxide-mediated oxidative stress in human neuronal-like cells (SKN-AS) determined by both MTT and flow cytometry (cell viability). These results were also confirmed by means of reactive oxygen species (ROS) production. Biodegradable poly(dl-lactic-co-glycolic acid) (PLGA) resomers assayed for microspheres preparation were PLGA-502 and PLGA-502H. Optimization by using an experimental design resulted in a formulation prepared with CQ (112 mg) and PLGA-502H (400 mg). With this formulation, mean encapsulation efficiency of 82.37% ± 6.67% and, zero-order release rate of 58 ± 3µg CQ/day/10 mg microspheres between Days 10 and 35 were obtained. Conclusion: We have developed a promising formulation for the treatment of Alzheimer’s disease.