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Anal Chem ; 90(7): 4832-4839, 2018 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-29513001


Raman spectroscopy is widely used for quantitative pharmaceutical analysis, but a common obstacle to its use is sample fluorescence masking the Raman signal. Time-gating provides an instrument-based method for rejecting fluorescence through temporal resolution of the spectral signal and allows Raman spectra of fluorescent materials to be obtained. An additional practical advantage is that analysis is possible in ambient lighting. This study assesses the efficacy of time-gated Raman spectroscopy for the quantitative measurement of fluorescent pharmaceuticals. Time-gated Raman spectroscopy with a 128 × (2) × 4 CMOS SPAD detector was applied for quantitative analysis of ternary mixtures of solid-state forms of the model drug, piroxicam (PRX). Partial least-squares (PLS) regression allowed quantification, with Raman-active time domain selection (based on visual inspection) improving performance. Model performance was further improved by using kernel-based regularized least-squares (RLS) regression with greedy feature selection in which the data use in both the Raman shift and time dimensions was statistically optimized. Overall, time-gated Raman spectroscopy, especially with optimized data analysis in both the spectral and time dimensions, shows potential for sensitive and relatively routine quantitative analysis of photoluminescent pharmaceuticals during drug development and manufacturing.

Corantes Fluorescentes/análise , Preparações Farmacêuticas/análise , Análise dos Mínimos Quadrados , Análise Espectral Raman , Fatores de Tempo
J Pharm Biomed Anal ; 145: 549-554, 2017 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-28759863


We introduce a system with a lyophilic matrix to aid dissolution studies of powders and particulate systems. This lyophilic matrix method (LM method) is based on the ability to discriminate between non-dissolved particles and the dissolved species. In the LM method the test substance is embedded in a thin lyophilic core-shell matrix. This permits rapid contact with the dissolution medium while minimizing dispersion of non-dissolved particles without presenting a substantial diffusion barrier. The method produces realistic dissolution and release results for particulate systems, especially those featuring nanoscale particles. By minimizing method-induced effects on the dissolution profile of nanopowders, the LM method overcomes shortcomings associated with current dissolution tests.

Nanopartículas , Difusão , Pós , Solubilidade
J Pharm Sci ; 105(8): 2293-7, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27368121


We introduce a robust, stable, and reproducible method to produce nanoparticles based on expansion of supercritical solutions using carbon dioxide as a solvent. The method, controlled expansion of supercritical solution (CESS), uses controlled mass transfer, flow, pressure reduction, and particle collection in dry ice. CESS offers control over the crystallization process as the pressure in the system is reduced according to a specific profile. Particle formation takes place before the exit nozzle, and condensation is the main mechanism for postnucleation particle growth. A 2-step gradient pressure reduction is used to prevent Mach disk formation and particle growth by coagulation. Controlled particle growth keeps the production process stable. With CESS, we produced piroxicam nanoparticles, 60 mg/h, featuring narrow size distribution (176 ± 53 nm).

Dióxido de Carbono/química , Composição de Medicamentos/métodos , Nanopartículas/química , Preparações Farmacêuticas/química , Cristalização , Composição de Medicamentos/instrumentação , Desenho de Equipamento , Tamanho da Partícula , Piroxicam/química , Pressão , Soluções , Termodinâmica
Int J Pharm ; 472(1-2): 82-7, 2014 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-24928131


In this study, microfluidic technology was employed to develop protein formulations. The microcapsules were produced with a biphasic flow to create water-oil-water (W/O/W) double emulsion droplets with ultrathin shells. Optimized microcapsule formulations containing 1% (w/w) bovine serum albumin (BSA) in the inner phase were prepared with poly(vinyl alcohol), polycaprolactone and polyethylene glycol. All the particles were found to be intact and with a particle size of 23-47 µm. Furthermore, the particles were monodisperse, non-porous and stable up to 4 weeks. The encapsulation efficiency of BSA in the microcapsules was 84%. The microcapsules released 30% of their content within 168 h. This study demonstrates that microfluidics is a powerful technique for engineering formulations for therapeutic proteins.

Composição de Medicamentos/métodos , Sistemas de Liberação de Medicamentos , Microfluídica , Polímeros/química , Soroalbumina Bovina/química , Cápsulas , Emulsões , Tamanho da Partícula , Porosidade , Solubilidade
Int J Pharm ; 441(1-2): 248-54, 2013 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-23200957


The aims were to prepare stable and well-dispersible pulmonary fine powders composed of combination drugs with different water solubility, to facilitate concomitant release of corticosteroid budesonide and short acting ß-agonist salbutamol sulphate and to improve the dissolution of the budesonide. The budesonide nanosuspensions were prepared by a wet milling which were mixed then with salbutamol sulphate, mannitol (bulking material) and leucine (coating material) for the preparation of micron-sized particles by an aerosol flow reactor wherein leucine formed a rough coating layer on particle surface. The stable and intact particle assemblies showed excellent aerosolization performance. The emitted doses from the inhaler, Easyhaler(®), were ~3 mg/dose with a coefficient variation of 0.1, and the fine particle fractions were ~50%. Complete dissolution of budesonide nanocrystals from the particles took place within 20 min with the same rate as salbutamol sulphate. Combining the two formulation technologies enabled the encapsulation of drugs with different solubility into a single, intact particle. The leucine coating provided excellent aerosolization properties which allowed fine powder delivery from the inhaler without carrier particles. This study showed the feasibility of preparing powders for combination therapy that are utilized, for instance, in inhalation therapy.

Albuterol/administração & dosagem , Budesonida/administração & dosagem , Sistemas de Liberação de Medicamentos , Excipientes/química , Administração por Inalação , Aerossóis , Albuterol/química , Broncodilatadores/administração & dosagem , Broncodilatadores/química , Budesonida/química , Combinação de Medicamentos , Composição de Medicamentos , Estudos de Viabilidade , Glucocorticoides/administração & dosagem , Glucocorticoides/química , Leucina/química , Manitol/química , Nanopartículas , Nebulizadores e Vaporizadores , Tamanho da Partícula , Solubilidade , Fatores de Tempo