Development And Validation Of A UV Spectrophotometric Method For The Assay Of Buspirone HCL Tablets

Buspirone is an azaspiro compound that is 8-azaspiro4.5] decane-7,9-dione substituted at the nitrogen atom by a 4-(piperazin-1-yl) butyl group which in turn is substituted by a pyrimidin-2-yl group at the N 4position. It has a role as an anxiolytic drug, a sedative, a serotonergic agonist and an EC 3.4.21.26 (prolyloligopeptidase) inhibitor. It is an azaspiro compound, a member of pyrimidines, a N-arylpiperazine, a N-alkylpiperazine, a member of piperidones and an organic heteropolycyclic compound. It is a conjugate base of a buspirone (1+). Buspirone is a novel anxiolytic agent with a unique structure and a pharmacological profile. Belonging to the azaspirodecanedione drug class, buspirone is a serotonin 5-HT1A receptor agonist that is not chemically or pharmacologically related to benzodiazepines, barbiturates, and other sedative/anxiolytic drugs. Unlike many drugs used to treat anxiety, buspirone does not exhibit anticonvulsant, sedative, hypnotic, and muscle-relaxant properties. Due to these characteristics, buspirone been termed 'anxioselective'. First synthesized in 1968 then patented in 1975, it is commonly marketed under the brand name Buspar®. Buspirone was first approved in 1986 by the FDA and has been used to treat anxiety disorders, such as generalized anxiety disorder (GAD), and relieve symptoms of anxiety. It has also been used as a second-line therapy for unipolar depression when the use of selective serotonin reuptake inhibitors (SSRIs) is deemed clinically inadequate or inappropriate. The potential use of buspirone in combination with [melatonin] in depression and cognitive impairment via promoting neurogenesis has also been investigated. (11) Buspirone is an azaspiro compound containing heteroaromatic moieties such as pyrimidine and piperazine rings, which function as chromophores capable of absorbing ultraviolet radiation (1)  There are few extractive spectrophotometric techniques for measuring Buspirone HCL in pharmaceutical matrices, according to a thorough analysis of the literature. Halogenated organic solvents, which pose serious environmental and occupational risks, are the main component of current analytical frameworks. Additionally, even though High-Performance Liquid Chromatography (HPLC) is still the gold standard for sensitivity and selectivity, high-throughput routine analysis is hampered by its operating costs and solvent consumption.(2)(10)
Our aim was to creating an extractive UV spectrophotometric technique that complies with Green Analytical Chemistry (GAC), the current study overcomes these constraints. The technique avoids the use of hazardous reagents while preserving analytical integrity by employing a 50:50 (v/v) water–ethanol hydro-ethanolic system. (4)(5)(6)

Figure 1: Structure of Buspirone HCL

MATERIAL AND METHODS:

MATERIAL:

Buspirone HCL (API), Buspirone HCL Tablet, Ethanol, Distilled Water

Instruments:

Analytical Balance (Shimadzu), UV- Visible Spectrophotometer (Shimadzu-1800), Sonicator

METHODS:

Preparation of Diluent:       

The solvent employed for the analysis consisted of a mixture of ethanol and distilled water at a ratio of 50:50 (v/v), ensuring Ideal solubility and transparency of the Buspirone HCL solution for UV spectroscopic assessment.

Preparation of Standard Stock Solution:

A stock solution was prepared by dissolving 10 mg of the Buspirone HCL in a 100 mL volumetric flask, followed by dilution to volume with the solvent and sonicated.

Preparation of sample:

As per the label claim, the buspirone tablet contain 5 mg drug. 20 tablets were weighed to determine weight uniformity, and the mean tablet weight was calculated to be 116 mg. The total weight of the 20 tablets was 2267 mg, corresponding to a labeled drug content of 20 mg of buspirone hydrochloride. The tablets were finely powdered using a pestle and mortar, and an amount of powder equivalent to 20 mg of buspirone hydrochloride was precisely transferred into a 100 mL volumetric flask. Sufficient amount of diluent added and sonicated for 30 min. with intermediate shaking made up volume up to 100 ml with diluent and mixed well.  

Determination of Maximum Wavelength (λ max):

A standard solution of Buspirone HCl was examined in the ultraviolet range of 200–400 nm using a UV–Visible spectrophotometer, with the prepared diluent serving as the blank baseline for correction. The absorption spectrum obtained exhibited a well-defined peak at 243 nm, which corresponds to the maximum absorbance of the drug. This wavelength (λ max) was selected for all further quantitative measurements and method validation studies, as it represents the point of highest sensitivity and accuracy for Buspirone HCL analysis (13) (14)

Validation:

The ICH Q2(R2) guidelines were followed in the validation of the developed UV-spectrophotometric method. Linearity, Accuracy, precision, Ruggedness limit of detection (LOD), and limit of Quantitation (LOQ) were among the validation parameters that were assessed. Along with respectable accuracy and precision, the method showed outstanding linearity over the chosen concentration range. The method's sufficient sensitivity was demonstrated by the low LOD and LOQ values. Overall, the validation results show that the suggested approach is accurate, dependable, and appropriate for routine quantitative analysis of Buspirone HCl in tablet dosage forms. (3) (12)

Linearty:

The linearity of Buspirone HCl was evaluated by preparing five standard solutions in the concentration range of 2.5–40 µg/mL from the standard stock solution. The absorbance of each solution was measured at the previously determined λ max of 243 nm using a UV–visible spectrophotometer, with 50:50 v/v ethanol: water as the blank. A calibration curve was constructed by plotting absorbance versus concentration, and linearity was assessed by calculating the correlation coefficient (R²). The results showed a direct and proportional relationship between absorbance and concentration over the studied range, indicating that the proposed method is linear and suitable for the quantitative determination of Buspirone HCl in both pure drug and tablet dosage forms. (7)(8)

Table 1: Result of Linearity

Figure 2: Calibration curve for Buspirone HCL (Concentration. vs. Absorbance.)

Table 2: Optimization parameters of Buspirone HCL Parameters Method values

Limit of Detection (LOD)

It was defined as the smallest concentration of an analyte in the sample which can be detected by the detector and it is not significant to undergo the linearity and precision test (it is not to be quantified)

Limit of Quantitation (LOQ)

It was defined as the smallest concentration of an analyte in the sample which can be detected by the detector and can be determined quantitatively with appropriate precision and accuracy and it can be calculated by using following equation according to the ICH (2005). (9)

LOD = 10/σ*S

LOQ = 3.3/σ*S

Table 3: Result of Absorbance

The LOD and LOQ of Buspirone HCL by the proposed method were found to be 0.094 µgml^-1 and 0.274µgml^-1respectively that is quite closed to practical value i.e. 0.05 for LOD and 0.25 for LOQ.

Actual LOD= 0.05 ppm

Actual LOQ = 0.25ppm

LOQ Precision:

Prepared sample of LOQ solution and recorded absorbance six times:

Table 4: Result of LOQ precision

Precision:

In precision intra-day and inter-day precision were performed at concentration (20µg/ml). The obtained results were found within limit i.e. less than 2%RSD.

Table 5: Results of method precision

Ruggedness (Intermediate Precision):

The change in analyst with same concentration and environmental condition didn’t affect the results.

Table 6: Results of Intermediate Precision

Absolute difference between method precision and intermediate precision  

Table 7: Result of difference between method and intermediate precision

Accuracy:

The concentration 10, 20, 30 µg/ml was taken as 50%,100%,150% and % recovery was found to be in range 98%-102%. Hence the parameter was found to be validated.

Table 8: Result of accuracy