Investigation of the Dissolution Profile of Gliclazide Modified-Release Tablets Using Different Apparatuses and Dissolution Conditions

Comparative dissolution studies on granules with acetaminophen and caffeine using the basket and paddle methods with simultaneous spectrophotometric determination of active substances

Acetaminophen and caffeine, popular therapeutic substances used to relieve pain or alleviate the symptoms of cold. The aims of the study were the comparison of granules, in terms of dissolution rate and moreover the development of spectrophotometric method to the simultaneous determination of both active pharmaceutical ingredients (APIs) in granules. The granules were tested by two pharmacopoeial methods of dissolution for solid dosage forms, and the dissolution profiles for each formulation were compared. A method of simultaneous determination of two medicinal substances by the double calibration method using derivative spectrophotometry was used. Considering the dissolution process carried out in the paddle apparatus, it was shown that more than 80% of acetaminophen and caffeine were released from each of the preparations in a clearly shorter time than 10 minutes. Carrying out the basket test, substances dissolved gradually, much slower than in the paddle method. The time required to release 80% of both active substances from majority of tested preparations was from 30 to 45 minutes. Application of the first derivative spectrophotometric method allows simultaneous determination of acetaminophen and caffeine in the mixture, without the need to separate them first.

Development of a Dissolution Method for Gliclazide Modified-Release Tablets Using USP Apparatus 3 with in Vitro-in Vivo Correlation

Gliclazide (GLZ) is a second generation hypoglycemic drug used for the treatment of Type 2 diabetes mellitus. The low solubility of GLZ has been described as the rate limiting step for drug dissolution and absorption, thus a prediction of its in vivo behavior based on a discriminative dissolution test should lead to a relevant in vitro-in vivo correlation (IVIVC). The aim of this study was to develop a dissolution method for GLZ modified-release (MR) tablets using an United States Pharmacopeia (USP) apparatus 3 through its evaluation by an IVIVC analysis. Various dissolution parameters were evaluated to establish an in vitro method for GLZ tablets. The final dissolution conditions, referred to as method 3, utilized a 400 µm mesh and 30 dips per minute over a total period of 10 h that included 1h in HCl media (pH 1.2), 2h in acetate buffer solution (pH 4.5), 1 h in phosphate buffer solution (PBS; pH 5.8), 5h in PBS (pH 6.8) and finally 1h in PBS (pH 7.2). The calculated point-to-point IVIVC (R²=0.9970) was significantly greater than other methods. The robustness of method 3 suggests it could be applied to pharmaceutical equivalence studies and for quality control analyses of GLZ.

The influence of physical division of tablets on the variability of release kinetics of gliclazide

Abstract

Tablets are often used in splitting process when the appropriated, registered dose is not available on the market or patients exhibit swallowing difficulties caused by the size of the tablet. The aim of the work was to assess the impact of physical division of tablets on the kinetics of in vitro gliclazide release from the intact and divided tablets. Gliclazide was released from prolonged release tablets containing 30 or 60 mg of the drug into a phosphate buffer, pH 7.4 and the amount of the drug in acceptor fluid was determined by UV–Vis spectrophotometry. The dissolution profiles were fit to zero- and first-order kinetics as well as to the Korsmeyer-Peppas equation. The largest discrepancy in the values of rate constants was obtained in the case of the release of gliclazide from intact and from splitting tablets using zero- and first-order kinetics. The values of the rate constants k₀ obtained from the release of the drug from the intact tablets and from fragments with a dose of the drug of 30 mg were (4.2 ± 0.1) × 10⁻⁵ g min⁻¹ and (5.8 ± 0.1) × 10⁻⁵ g min⁻¹, respectively, and k₁ were (2.3 ± 0.1) × 10⁻³ min⁻¹ and (4.7 ± 0.6) × 10⁻³ min⁻¹, respectively. These discrepancies were confirmed by the value of f₂ coefficient that was 45.9. The results suggest that physical division of tablets accelerate the release of gliclazide from its prolonged form.

Graphical abstract