276 Granada et al.: Journal of aoaC InternatIonal V ol. 96, no. 2, 2013 Nifedipine-Loaded Polymeric Nanocapsules: Validation of a Stability-Indicating HPLC Method to Evaluate the Drug Entrapment Effciency and In Vitro Release Profles AndréA GrAnAdA and MonikA PiAzzon T AGliAri Universidade Federal de Santa Catarina, Departamento de Ciências Farmacêuticas, Centro de Ciências da Saúde, UFSC, Florianópolis-SC, Brazil V Aldir Soldi Universidade Federal de Santa Catarina, Departamento de Química, Centro de Ciências Físicas e Matemáticas, UFSC, Florianópolis- SC, Brazil MArcoS AnTônio SeGATTo SilVA Universidade Federal de Santa Catarina, Departamento de Ciências Farmacêuticas, Centro de Ciências da Saúde, UFSC, Florianópolis-SC, Brazil BeTinA Ghiel zAneTTi-rAMoS Encapsulados de Alta Tecnologia, Departamento de Pesquisa, Desenvolvimento e Inovação, Nanovetores, Florianópolis, SC, Brazil dAniel FernAndeS Universidade Estadual de Ponta Grossa, Departamento de Ciências Farmacêuticas, Centro de Ciências da Saúde, UEPG, Ponta Grossa-PR, Brazil hellen kArine STulzer Universidade Federal de Santa Catarina, Departamento de Ciências Farmacêuticas, Centro de Ciências da Saúde, UFSC, Florianópolis-SC, Brazil Received April 3, 2011. Accepted by SW May 22, 2011. 1 Corresponding author’s e-mail: hellen.stulzer@gmail.com DOI: 10.5740/jaoacint.11-050 DRUG FORMULATIONS AND CLINICAL METHODS A simple stability-indicating analytical method was developed and validated to quantify nifedipine in polymeric nanocapsule suspensions; an in vitro drug release study was then carried out. The analysis was performed using an RP C18 column, UV-Vis detection at 262 nm, and methanol–water (70 + 30, v/v) mobile phase at a fow rate of 1.2 mL/min. The method was validated in terms of specifcity, linearity and range, LOQ, accuracy, precision, and robustness. The results obtained were within the acceptable ranges. The nanocapsules, made of poly(ε-caprolactone), were prepared by the solvent displacement technique and showed high entrapment effciency. The entrapment effciency was 97.6 and 98.2% for the nifedipine-loaded polymeric nanocapsules prepared from polyvinyl alcohol (PVA) and Pluronic F68 (PF68), respectively. The particle size and zeta potential of nanocapsules were found to be infuenced by the nature of the stabilizer used. The mean diameter and zeta potential for nanocapsules with PVA and PF68 were 290.9 and 179.9 nm, and –17.7 mV and –32.7 mV, respectively. The two formulations prepared showed a drug release of up to 70% over 4 days. This behavior indicates the viability of this drug delivery system for use as a controlled-release system. N anoparticle is a general name used to describe nanocapsules and nanospheres, that is, submicron carriers with nanometric size (1). According to the literature, a nanocapsule comprises a polymeric wall enveloping an oil core, whereas a nanosphere consists of a polymeric matrix (2). Nanoparticle suspensions have been developed as drug targeting delivery systems using polyesters, poly (alkylcyanoacrylate), poly (alkyl methacrylate-coacrylic acid), poly(lactide) acid, poly(ε-caprolactone; PCL), poly (lactide-co-glycolide), and other polymers (3, 4). Biodegradable polymers have been the major focus of attempts to develop improved delivery systems for pharmaceutical research. PCL is a semicrystalline polymer, toxicity free, with longer hydrocarbon segments and slower hydrolytic degradation than other major polymers. The excellent biocompatibility and biodegradability of PCL nanoparticles make them well suited for oral drug delivery (5, 6). The literature does not show the uses of this polymer for the development of nanocapsules with nifedipine (NFP). NFP (1,4-dihydro-2,6-dimethyl-4- (2-nitrophenyl)-3,5- pyridine dicarboxylic acid dimethyl ester) is a calcium channel blocker that has been widely used for the treatment of hypertension, angina, and myocardial infarction. NFP has a very low bioavailability and is thermally unstable (7). NFP is a suitable candidate for sustained-release formulation administration due to its short elimination half-life of 2 to 4 h, its rapid and complete drug absorption over the entire gastrointestinal tract despite its low water solubility, and the relationship between drug plasma concentrations and blood pressure reduction. The importance of reduced peak plasma levels in order to avoid adverse effects such as tachycardia has also been demonstrated (8). NFP undergoes faster degradation in normal sunlight than under exposure to an electric light bulb (9). As a result, there are many reports of improved NFP solubility and physical stability in a wide variety of formulations. Examples include microparticles (10–12), lipid nanoparticles (13), solid dispersions (14), inclusion complexes (15), nanocrystals (16), Downloaded from https://academic.oup.com/jaoac/article/96/2/276/5654914 by guest on 21 April 2023