Development and Validation of a Spectrophotometric Method for Analysis of Liquisolid Compacts Containing a Poorly Water-Soluble Drug (Clopidogrel)
摘要
Liquisolid compact is a novel approach to modifying drug release. In liquisolid compacts liquid medication (liquid drug or solution/dispersion of a drug prepared in a nonvolatile solvent) is converted to a dry powder suitable for compression. Formulation development of liquisolid compacts involves evaluation at different levels and a simple, rapid, cost-effective, and accurate analytical method was needed to facilitate the process. Nonvolatile oils used in the formulation of liquisolid compacts interfere with their analysis. The current study was aimed at developing an economical, simple, accurate, and time-saving method of analysis for liquisolid compacts of clopidogrel. In the present study, the solubility of clopidogrel was used as a basis for the selection of solvent. Equilibrium solubility of clopidogrel in different solvents was determined by the flask-shaking method. A solution of clopidogrel in a selected solvent was scanned within the range 200–400 nm, using a double-beam UV-visible spectrophotometer and the wavelength of maximum absorbance was selected. After proper optimization of the experimental parameters, validation of the developed method was carried out as per United States Pharmacopeia and International Council for Harmonisation protocols. Different validation parameters such as linearity, specificity, precision, accuracy, and sensitivity were evaluated as per standard guidelines. The applicability of the method was assessed by evaluation of liquisolid compacts of clopidogrel, prepared with different liquid load factors in one of our previous studies. According to the Biopharmaceutical Classification System, clopidogrel is a class II drug with poor water solubility. Compared with other organic solvents, the highest solubility of clopidogrel was observed in methanol (139.72 μg/mL), which was used as a solvent throughout the study. The developed method showed better linearity at a concentration of 0–100 μg/mL (R2 = 0.9994). The main problem with the analysis of liquisolid compacts is interference by the nonvolatile oils used in their formulation. In the current study, there was no interference of the excipients, and percentage recovery, with and without excipients, was close to 100%. The stability of clopidogrel solution in methanol was evaluated at ambient temperature (25 ± 2°C), refrigerator temperature (2–8°C), and higher temperature (40 ± 2°C). The drug solution remained stable for 72 h and the percentage recovery was within a permissible range. The analysis of the liquisolid compact, having a different load factor, showed that the method can be applied for the analysis of clopidogrel in liquisolid compacts and conventional tablets. In conclusion, the developed UV-visible spectrophotometric method will be an alternative to the high-performance liquid chromatography-based method of analysis for clopidogrel as it is rapid, cost effective, and accurate. It will facilitate evaluation of liquisolid compacts of clopidogrel at different stages of formulation development.