Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Comparative investigation of two different self-organizing map-based wavelength selection approaches for analysis of binary mixtures with strongly overlapping spectral lines

Lawan Sratthaphut¹ , Sathit Niratisai², Onoomar Toyama²

¹Department of Health-related Informatics; ²Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Silpakorn University, Nakhon Pathom, Thailand.

For correspondence:- Lawan Sratthaphut Email: sratthaphut_l@su.ac.th Tel:+6634253910

Received: 1 February 2017 Accepted: 18 June 2017 Published: 31 July 2017

Citation: Sratthaphut L, Niratisai S, Toyama O. Comparative investigation of two different self-organizing map-based wavelength selection approaches for analysis of binary mixtures with strongly overlapping spectral lines. Trop J Pharm Res 2017; 16(7):1693-1702 doi: 10.4314/tjpr.v16i7.30

© 2017 The authors.
This is an Open Access article that uses a funding model which does not charge readers or their institutions for access and distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0) and the Budapest Open Access Initiative (http://www.budapestopenaccessinitiative.org/read), which permit unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited..

Abstract

Purpose: To demonstrate the ability and investigate the performance of two different wavelength selection approaches based on self-organizing map (SOM) technique in partial least-squares (PLS) regression for analysis of pharmaceutical binary mixtures with strongly overlapping spectra.

Methods: Two different variable selection methods were compared, namely, SOM1-PLS and SOM2-PLS. The main difference between these methods involved the structure of neurons in input layer and the algorithm for variable selection. Adjustable parameters for each technique were optimized for better comparison. The performance of these methods was statistically verified for predictive ability using both synthetic mixtures and a real combination product of sulfamethoxazole (SMX) and trimethoprim (TMP), which exhibited strongly overlapping of spectral lines.

Results: The results obtained indicate that SOM2-PLS was more efficient than SOM1-PLS technique with 30 and 6 % improvement in predictive ability for SMX and TMP, respectively. Furthermore, the mean difference between the results obtained from SOM2-PLS method and those from the official method was not statistically significant as p-value was more than 0.01.

Conclusion: Although, SOM2-PLS method is more efficient than SOM1-PLS method for the analysis of pharmaceutical binary mixtures with severely overlapping spectra, some problems associated with SOM2-PLS technique include difficult computations of some parameters.

Keywords: Co-trimoxazole, Self-organizing map, Wavelength selection, Pharmaceutical analysis, Overlapping spectral lines