DRUG FORMULATIONS AND CLINICAL METHODS Development and Validation of an HPLC Method to Quantify Camptothecin in Polymeric Nanocapsule Suspensions ANDRÉA GRANADA Universidade Federal de Santa Catarina, Departamento de Ciências Farmacêuticas, Laboratório de Farmacotécnica, Campus Universitário Trindade, Florianópolis, SC 88040-900, Brazil FABIO S. MURAKAMI Universidade Federal de Santa Catarina, Departamento de Ciências Farmacêuticas, Laboratório de Controle de Qualidade, Campus Universitário Trindade, Florianópolis, SC 88040-900, Brazil TATIANE SARTORI and ELENARA LEMOS-SENNA 1 Universidade Federal de Santa Catarina, Departamento de Ciências Farmacêuticas, Laboratório de Farmacotécnica, Campus Universitário Trindade, Florianópolis, SC 88040-900, Brazil MARCOS A.S. SILVA Universidade Federal de Santa Catarina, Departamento de Ciências Farmacêuticas, Laboratório de Controle de Qualidade, Campus Universitário Trindade, Florianópolis, SC 88040-900, Brazil A simple, rapid, and sensitive reversed-phase column high-performance liquid chromatographic method was developed and validated to quantify camptothecin (CPT) in polymeric nanocapsule suspensions. The chromatographic separation was performed on a Supelcosil LC-18 column (15 cm ´ 4.6 mm id, 5 mm) using a mobile phase consisting of methanol–10 mM KH 2 PO 4 (60 + 40, v/v; pH 2.8) at a flow rate of 1.0 mL/min and ultraviolet detection at 254 nm. The calibration graph was linear from 0.5 to 3.0 mg/mL with a correlation coefficient of 0.9979, and the limit of quantitation was 0.35 mg/mL. The assay recovery ranged from 97.3 to 105.0%. The intraday and interday relative standard deviation values were <5.0%. The validation results confirmed that the developed method is specific, linear, accurate, and precise for its intended use. The current method was successfully applied to the evaluation of CPT entrapment efficiency and drug content in polymeric nanocapsule suspensions during the early stage of formulation development. C amptothecin (CPT; Figure 1) belongs biogenetically to a family of modified monoterpenoid indole alkaloids. This drug has shown a high antitumor activity against a wide spectrum of malignancies, in which the mechanism involves the inhibition of topoisomerase I, an enzyme involved in the DNA replication, recombination, and transcription process. CPT encloses in its structure a highly conjugated pentacyclic ring with a a-hydroxylactone portion at carbon 12, which is essential for its in vitro and in vivo activity. However, the full utility of CPT has still not been achieved therapeutically, which is mainly due to its low water solubility and low stability in the physiological medium. After intravenous administration, CPT undergoes a fast nonenzymatic hydrolysis of the lactone ring, forming a less active and more toxic product known as the carboxylate form (1). The decreasing of the cell membrane binding, membrane diffusibility, and intrinsic potency against the topoisomerase target has been connected with the reduction in cytotoxic activity that accompanies the lactone ring opening of camptothecin (2). The development of a new controlled release strategy is greatly called for to promote a better clinical use for this drug (3). Over the past few decades, there has been considerable interest in the development of biodegradable nanoparticles as effective drug delivery systems. These colloidal carriers have shown the following advantages: drug protection against in vivo degradation, increase of the bioavailability of poorly water-soluble drugs, and ability to control the drug release (4). Nanoparticles also modify the kinetics and body distribution, leading to the reduction of systemic toxicity of an associated drug (5). A number of different polymers have been used to prepare nanoparticles as drug carriers; however, poly (D,L-lactide; PLA) is by far preferable, due to its biodegradation and biocompatibility characteristics. PLA nanoparticles are rapidly removed from systemic blood circulation by the cells of the mononuclear phagocyte system following intravenous administration. The rapid removal of conventional nanoparticles from the bloodstream has limited the drug from arriving at other organs rather than at the liver and the spleen. In this regard, particles that display hydrophilic surface coating, such as polyethylene glycol (PEG), are designed to resist GRANADA ET AL.: JOURNAL OF AOAC INTERNATIONAL VOL. 91, NO. 3, 2008 551 Received July 18, 2007. Accepted by SW October 7, 2007. 1 Author to whom correspondence should be addressed; e-mail: lemos@ccs.ufsc.br Downloaded from https://academic.oup.com/jaoac/article-abstract/91/3/551/5656062 by guest on 22 July 2020