Determination of Albendazole Content in Albendazole Tablets using UV Spectroscopy

Abstract

Albendazole is a commonly used anti-helminthic drug belonging to the benzo-imidazole derivatives. It is a broad-spectrum anthelmintic that works by exerting an inhibitory effect on tubulin polymerization which results in the loss of cytoplasmic microtubules. Kenya suffers from a huge burden of helminthic diseases, with an estimated five million school going children being affected. It is therefore imperative that the medications in the market be of the correct dosages. The purpose of this study is to determine the concentration of albendazole in tablet formulation by using UV spectroscopy to ensure that it meets the required specifications for potency and dosage accuracy. Albendazole tablets were obtained from a number of pharmacies and hospitals in Meru Kenya, weighed, powdered diluted and their absorbance recorded using UV spectroscopy. The label claim amount of the tablets was found to be from 388.79 mg- 446.28 (97.20%-111.57%), with weight variations of 0.6340-7.6254 for the maximum and -0.7093 to -4.4067 for the minimum variation. Majority of the sampled brands complied with assay and weight specifications for albendazole as outlined by the international pharmacopeia.

Keywords

Introduction

Albendazole (ALB) is a broad spectrum anti-helminthic medication that is structurally similar to mebendazole and is available in tablet (400 mg) and oral suspension formulations ^[1]. It was first proven to be effective against gastrointestinal nematodes in 1961 by brown and team and then marketed in 1982 for use in humans ^[2]. The Food and Drug Administration has approved albendazole for treating a variety of parasitic worm infections including cystic hyatid disease, parenchymal neurocysticercosis, ancylostoma, ascariasis and capillariasis amongst others ^[3].

As per the recent FDA quality guidelines, a chewable tablet should be easy to chew, palatable, of appropriate shape and size and able to disintegrate readily to facilitate dissolution ^[4]. Critical quality attributes for chewable tablets include hardness, weight uniformity, disintegration, assay and dissolution as well as factors that may influence drug bioavailability and bioequivalence ^[5]. There are several analytical methods available for assay of albendazole including High Performance Liquid Chromatography (HPLC), gas chromatography, titrimetric method, capillary electrophoresis and UV spectroscopy ^[6].

UV spectroscopy is a widely used analytical technique for the determination of Albendazole in pharmaceutical formulations. It is a non-destructive, rapid and cost-effective method that is based on the measurement of the absorbance of light by the drug molecule (Beer lambert’s principle) ^[7]. The beer lambert’s law state that the amount of light absorbed is directly proportional to the concentration of the analyte ^[8]. Albendazole has a characteristic absorption at 290 nm.

MATERIALS AND METHODS

Study Area

This study was conducted at the pharmaceutical chemistry lab of Kenya Methodist University.

Sample collection

Samples of various brands of albendazole tablets were collected from random pharmacies and hospitals in Meru County. According to the pharmacopeia specification ten tablets of each brand were collected and stored in zipped polythene bags before transportation to the lab.

Sample preparation

The sample preparation and analysis was carried out according to the specifications by the international pharmacopeia ^[9]. All tablets were weighed individually using a calibrated analytical balance and the weights recorded down. The tablets were then crushed by a mortar and pestle into powder form. A quantity of the powder containing an equivalent weight of 20 mg of ALB was accurately weighed and transferred to a 50 mL volumetric flask and 30 mL of hydrochloric acid/methanol solvent mixture added (0.01M). The mixture was then sonicated for15 minutes and diluted to volume with the solvent mixture. 10 mL of the resulting solution was then transferred to a 50 mL volumetric flask and diluted to volume with 0.1 M sodium hydroxide.  

Measuring absorbance

The absorbance of the final solution was measured at a maximum wavelength of 308 nm with sodium hydroxide as the blank using UV spectroscopy.

Data analysis and interpretation

Weight and absorbance readings obtained were entered into a pre-structured excel sheets that determined the concentrations.

RESULTS AND DISCUSSIONS

Weight Variation

The pharmacopeia specifies that the acceptable level of weight variation is +/- 5 % for tablets whose average weight is above 250 mg. From results presented in table 1 all of the tablets except brand A comply with the specification. Since no more than two tablets should exceed the limit, brand c therefore complies with the average weight specification. High or lower variations are caused by differences in amount of active pharmaceutical ingredients or excipients amongst the individual tablets. This could be caused by factors such as inconsistent mixing during production, inadequate compression factor, uneven feeding of powder from drum and variations in tablet press settings amongst others.

Table 1 Weight Variation

Assay

According to the international pharmacopeia, ALB chewable tablets contain albendazole content of not less than 90% and not more than 110% of the amount of albendazole 400mg. The results obtained indicated that nine out of ten samples collected complied with this specification. Sample A had a higher value of 111.6% which was above the acceptable limit. This higher value could probably be caused by excipients presented in ALB absorbing at the same wavelength as ALB therefore increasing the absorbance value. This can be solved by use of HPLC in analysis instead of UV. HPLC is a precise robust and selective method that will only use the area under the curve of ALB only. Due to the unavailability of a standard necessitated the use of UV instead of HPLC. 

Table 2 Assay percentage label claim

CONCLUSION

This study finds that the concentration of albendazole in tablet formulations from  Meru County comply with the pharmacopeia specification of weight variation and assay and therefore meet the required specifications for potency and dosage accuracy. The albendazole tablet formulations are therefore safe and effective for use in management of various parasitic infections.

REFERENCES

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