Determination of diltiazem hydrochloride in human serum by high-performance liquid chromatography

Modulation of Drug Release from Natural Polymer Matrices by Response Surface Methodology: in vitro and in vivo Evaluation

Purpose

The present work aimed at challenging the efficacy of natural gums, karaya and locust bean gum, as matrix-forming polymers for the formulation of sustained-release tablets of diltiazem, a model drug.

Methods

Central design composite was adopted for the formulation and optimization of tablet formulations. The two gums have been selected as independent variables. The dependent factors chosen were the amount of drug released in 1st hour (Y1), amount of drug released after 12 h (Y2), diffusion exponent (Y3), and time for half of the total drug released (T_50%) (Y4). Wet granulation approach was used for the formulation of tablets. FT-IR, DSC, in vitro dissolution, swelling-erosion investigations, SEM, and stability studies were carried out.

Results and Discussion

It was evident that the release pattern from the prepared formulations was significantly influenced by the quantity of gum(s) in the tablet. FT-IR and DSC results confirm drug-polymer compatibility. Polynomial equations were used for the prediction of quantitative impact of independent factors at different levels on response variables. After ANOVA analysis, the significant factors were considered for constrained optimization to get the optimized formula. The optimized formula generated by the response surface methodology was evaluated both for in vitro and in vivo properties. The optimized formula and a sustained-release marketed product were subjected to in vivo studies in rabbits and the results of the t-test demonstrated insignificant variation in pharmacokinetic parameters among the two formulations, confirming that the prepared tablet showed sustained-release profile.

Conclusion

The results indicated that karaya and locust bean gum can be effectively used to formulate sustained-release tablets.

Green fabrication of 3D hierarchical blossom-like hybrid of peeled montmorillonite-ZnO for in-vitro electrochemical sensing of diltiazem hydrochloride drug

Herein, a 3D hierarchical blossom-like of Montmorillonite-ZnO (MMt/ZnO) micro-hybrids modified sensors have been successfully fabricated as an extraordinarily electrochemical sensor for detecting of the Diltiazem hydrochloride (DZM.HCl). The 3D hierarchical blossom-like of ZnO and series of MMt/ZnO hybrids have been synthesized using different contents of MMt [FMZ_1-5] via a hydrogel polymer template method using alginate ions. The effect of incorporation of different contents of MMt on the morphology, surface area of hybrids were investigated using Fourier transform infrared (FTIR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Energy-dispersive X-ray spectroscopy (EDS), Brunauer-Emmett-Teller (BET) surface area method, and High-resolution transmission electron microscopy (HR-TEM). The obtained hybrid [FMZ₃] with 2.0% of MMt presented the most perfect blossom-like morphology and the highest surface area (190.06 m²/g) with the lowest resistivity. The hierarchical structure of [FMZ₃] reveals nanospheres of ZnO with an average diameter of 5.49 nm, which are assembled into nanorods followed by assembling to form a blossom-like shape with the inclusion of MMt peeled layers inside the rod with d-spacing ranges from 1.1-7.4 nm. Meanwhile, the implemented modified sensor 1.0% [FMZ₃] CPS retained excellent conductivity and electrocatalytic activity as appraised from the cyclic voltammetry (CV) measurements. Consequently, the electrochemical behavior and the oxidation mechanism of DZM.HCl drug has been investigated at the surface of the constructed sensor. Under the optimum operational conditions, the proposed sensor was successfully achieved detection limits 0.177, and 0.21 nmol·L^-1 of DZM.HCl in a commercial and human biological fluid (Serum samples), respectively. The constructed sensor accomplished an appropriate accuracy and free of obstruction from other ordinarily drug excipients.

A clinical therapeutic protein drug-drug interaction study: coadministration of denosumab and midazolam in postmenopausal women with osteoporosis

Drug–disease interactions involving therapeutic proteins that target cytokines and potentially impact cytochrome P450 (CYP) enzymes have been of increased interest to drug regulatory agencies and industry sponsors in recent years. This parallel-group open-label study evaluated the effects of the monoclonal antibody denosumab, an inhibitor of the cytokine RANKL, on the pharmacokinetics of the probe CYP3A4 substrate midazolam in postmenopausal women with osteoporosis. The pharmacokinetics of a 2 mg oral dose of midazolam was evaluated on days 1 and 16. Subjects in Group A received a 60 mg subcutaneous dose of denosumab on day 2, 2 weeks before the second midazolam dose, while subjects in Group B did not. For Group A (n = 17), point estimates for the ratio of least square means for midazolam exposures based on maximum observed plasma concentration (C_max) and areas under the plasma concentration–time curve (AUCs) on day 16 versus day 1 ranged from 1.02 to 1.04 and 90% confidence intervals were within 0.80–1.25. No period effect was observed for Group B (n = 8). Midazolam and denosumab coadministration was safe and well tolerated. Inhibition of the cytokine RANKL by denosumab does not affect CYP3A4 in postmenopausal women with osteoporosis and will not alter the pharmacokinetics of drugs metabolized by this enzyme. These results are consistent with data suggesting that RANKL does not impact markers of inflammation and represent the first clinical data demonstrating a lack of effect on CYP3A4 of a therapeutic protein that is a cytokine modulator.

An Overview of Analytical Determination of Diltiazem, Cimetidine, Ranitidine, and Famotidine by UV Spectrophotometry and HPLC Technique

This review article recapitulates the analytical methods for the quantitative determinations of diltiazem and three H2receptor antagonists (cimetidine, ranitidine, and famotidine) by one of the spectroscopic technique (UV spectrophotometery) and separation technique such as high-performance liquid chromatography (HPLC). The clinical and pharmaceutical analysis of these drugs requires effective analytical procedures for quality control, pharmaceutical dosage formulations, and biological fluids. An extensive survey of the literature published in various analytical and pharmaceutical chemistry-related journals has been compiled in its review. A synopsis of reported spectrophotometric and high-performance liquid chromatographic methods for individual drug is integrated. This appraisal illustrates that majority of the HPLC methods reviewed are based on the quantitative analysis of drugs in biological fluids, and they are appropriate for therapeutic drug monitoring purpose.

Indirect spectrophotometric determination of diltiazem hydrochloride in pure form and pharmaceutical formulations

Three simple, accurate, and sensitive spectrophotometric methods (A, B and C) have been described for the indirect assay of diltiazem hydrochloride (DIL.HCl), either in pure form or in pharmaceutical formulations. The first method (A) is based on the oxidation of DIL.HCl by N-bromosuccinimide (NBS) and determination of unconsumed NBS by measuring the decrease in absorbance of amaranth dye (AM) at a suitable λmax=521 nm. Other methods (B) and (C) involve the addition of excess cerric ammonium sulfate (CAS) and subsequent determination of the unconsumed oxidant by a decrease in the red color of chromotrope 2R (C2R) at a suitable λmax=528 nm or a decrease in the orange-pink color of rhodamine 6G (Rh6G) at λmax=525 nm, respectively. Regression analysis of Beer-Lambert plots showed good correlation in the concentration ranges 3.0–9.0, 3.5–7.0 and 3.5–6.3 μg ml−1 for methods A, B and C, respectively. The apparent molar absorptivity, Sandell's sensitivity, detection and quantification limits were calculated. The proposed methods have been applied successfully for the analysis of the drug in its pure form and its dosage form. No interference was observed from a common pharmaceutical adjuvant. Statistical comparison of the results with the reference method shows excellent agreement and indicates no significant difference in accuracy and precision.