The toxic profile of chemical cross-linkers
used in enhancing the
stability of self-assembled nanomicelles made of amphiphilic polymeric
materials hinders their use in clinical applications. This study was
aimed to use the layered structure of Na-montmorillonite (MMT) as
a stabilizer for nanomicelles made of poly(d,l-lactide-co-glycolide) (PLGA) amphiphilic polymer. The size of Na-MMT
was reduced below 40 nm (nano-MMT) by processing in an attritor prior
to its incorporation with PLGA. Hybrid PLGA nano-MMT (PM) nanoparticles
(NPs) were prepared using dialysis nanoprecipitation. The size distribution
was measured using dynamic light scattering (DLS). Loading 1250 μg
of the model drug molecule curcumin to PM (PMC) resulted in obtaining
88 nm-sized particles, suitable for passive targeting of cancer tumors.
The structure of nano-MMT and its position in PMC were investigated
using FT-IR, differential scanning chalorimetry (DSC), XRF, XRD, ESEM,
and EDAX assays, all of which showed the exfoliated structure of nano-MMT
incorporated with both hydrophilic and hydrophobic blocks of PLGA.
Curcumin was mutually loaded to PLGA and nano-MMT. This firm incorporation
caused a serious extension in the release of curcumin from PMC compared
to PLGA (PC). Fitting the release profile to different mathematical
models showed the remarkable role of nano-MMT in surface modification
of PLGA NPs. The ex vivo dynamic model showed the
enhanced stability of PMC in simulated blood flow, while cytotoxicity
assays showed that nano-MMT does not aggravate the good toxic profile
of PLGA but improves the anticancer effect of payload. Nano-MMT could
be used as an effective nontoxic stabilizer agent for self-assembled
NPs.
Aim: A new HPLC method with fluorescence detection has been developed and validated for the determination of levofloxacin, one of the fluoroquinolone class antibiotics, in breast milk. Materials & methods: Chromatographic separation was carried out on a reversed phase C18 column with acetonitrile and 10 mM o-phosphoric acid (25:75,v/v) mobile phase composition. Moxifloxacin was used as internal standard and the peaks were detected by fluorescence detection. Results & conclusion: Calibration graph was found linearly within the range of 2.5–500 ng/ml. Limit of detection and limit of quantification were found to be 0.63 and 2.11 ng/ml, respectively. Mean absolute recovery was 96.18%. The developed method has been successfully applied to the determination of levofloxacin in human breast milk taken from two healthy volunteers.
In this study, a new size exclusion chromatographic method has been developed and validated for the analysis of mucopolysaccharide polysulfate used as an anti-inflammatory and antithrombotic agent in topical formulations.
In the present study, two new methods were developed and validated for the determination of rilmenidine in bulk and pharmaceutical preparation. Both methods are based on a derivatization reaction using 4-chloro-7-nitro-1,2,3-benzoxadiazole (NBD-Cl) as a fluorogenic substance. The drug reagent derivatives were formed by the reaction of rilmenidine with NBD-Cl at pH 9.0 at 70°C for 40 min. The reaction mixtures were analyzed by spectrofluorimetry in the first method and high performance liquid chromatography (HPLC) in the second method. Derivatives were determined at λex 493 nm and at λem 536 nm in the spectrofluorimetric method. The separation was performed place on a Phenomenex, C18 column (250 × 4.6 mm, 5 μm i.d) using a mobile phase comprising 0.2% formic acid and acetonitrile gradient elution mode in the HPLC method. Analytes were detected by a fluorescence detector at the same wavelength. The methods were validated for limit of quantitation, linearity, robustness, recovery, limit of detection, precision and accuracy. Calibration curves for the first and second methods were found to be linear in the range of 2.0–12.0 and 250–2000 ng/mL, respectively. Detection limits for the spectrofluorimetric and HPLC methods were calculated as 0.16 and 18.28 ng/mL, respectively. The validated methods were applied successfully to the determination of rilmenidine in bulk and pharmaceutical preparation.
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