μÀÑ Determination of ivermectin stability by high-performance thin-layer chromatography

A rapid, sensitive and stability-signifying high-performance thin-layer chromatographic (HPTLC) method was developed and validated for the quantitative estimation of ivermectin (IVM) as a bulk drug and in pharmaceutical formulations. The separation was achieved on Lichrospher TLC aluminum plates pre-coated with silica gel 60F-254 (20cm×10cm×200 μm) using n-hexane: acetone: ethylacetate (6.5: 3.5: 0.1 v/v/v) as mobile phase. The densitometric analysis was carried out at 247 nm wavelength. Compact spots of IVM were found at Rf = 26±0.02. For proposed procedure, linearity (r2 = 0.9989), limit of quantification (24.9 ng spot−1), limit of detection (8.22 ng spot−1) recovery (98.25–100.16%), and inter as well intra-day precision (≤2.21) was found to be satisfactory. We have synthesized polymeric nanoparticles encapsulated formulation of ivermectin (IVM-NPs); ut il izing micellar aggregates of cross-linked random copolymer Nisopropylacrylamide (NIPAAM) with N-vinyl-2-pyrrolidone (VP) and polyethyleneglycol monoacrylate (PEG-A) for lymphatic targeting and i t was also quantified by the developed method. IVM and formulations were subjected to acid and alkali hydrolysis, oxidation and photo-degradation. The drug undergoes degradation under acidic, basic, light and oxidation conditions. This indicates that the drug is susceptible to acidbase hydrolysis, oxidation and photo-oxidation and the developed method is selective for quantifying IVM even in the presence of degradatnts. The method was applicable for routine analysis and stability testing of IVM in pharmaceutical drug delivery systems. As the method could effectively separate the said drug from its degradation products, it can be employed as a stability indicating one. *Corresponding author, Mailing address: Dr. Farhan Jalees Ahmad (Associate Professor) Department of Pharmaceutics, F/O Pharmacy, Hamdard University, Hamdard Nagar, New Delhi-110062, India. Mobile No. +91-9810720387; Fax No. +91-11-26059663 [email protected] F u l l L e n g t h R e s e a r c h P a p e r C o v e r e d i n O f f i c i a l P r o d u c t o f E l s e v i e r , T h e N e t h e r l a n d s Article History:-----------------------Date of Submission: 07-05-2011 Date of Acceptance: 01-06-2011 Conflict of Interest: NIL Source of Support: NONE Int. J. Drug Dev. & Res., April-June 2011, 3 (2): 240-247 Covered in Scopus & Embase, Elsevier 240 avermiltilis [1-2]. IVM has broad spectrum activity against arthropod parasites located in the different layers of skin and nematode parasites located in gastrointestinal and pulmonary tracts [2-3]. It exerts its action by opening γ-aminobutyric acid (GABA) channel-I and thus widely employed in the treatment of scabies, onchocerciasis, strongyloidiasis, ascariasis, trichuriasis and enterobiasis [2-5]. Lymphatic targeting of IVM using polymeric nanoparticles holds a great potential. Stability of IVM during formulation development of polymeric nanoparticles is key to a successful formulation. High-performance liquid chromatograpy [6-15], liquid chromatography with tandem mass spectrometry [18,19], liquid chromatography with electrospray ionization mass spectrometry [20,21], high-speed counter-current chromatography [22] and capillary electrophoresis [23] for determination of IVM as a bulk drug and in dosage forms, biological fluids as well as in human and animal body tissues has been reported in the literature. However, no published analytical technique focuses on stability testing of IVM. The present work aimed at determination of acid-base, oxidation, hydrolytic and photolytic stability of IVM by high-performance thinlayer chromatographic (HPTLC) method. The developed HPTLC method is validated for linearity, precision, accuracy, sensitivity, selectivity and robustness. The method is also applied for determination of IVM content in the prepared nanoformulation of IVM (Nano-IVM).