A Validated RP-HPLC Method for Simultaneous Estimation of Nebivolol and Hydrochlorothiazide in Tablets

An empirical predictive model for determining the aqueous solubility of BCS class IV drugs in amorphous solid dispersions

CONTEXT

Determining solubility of drugs is laborious and time-consuming process that may not yield meaningful results. Amorphous solid dispersion (ASD) is a widely used solubility enhancement technique. Predictive models could streamline this process and accelerate the development of oral drugs with improved aqueous solubilities.

OBJECTIVE

This study aimed to develop a predictive model to estimate the solubility of a compound from the ASDs in polymer matrices.

METHODS

ASDs of model drugs (acetazolamide, chlorothiazide, furosemide, hydrochlorothiazide, sulfamethoxazole) with model polymers (PVP, PVPVA, HPMC E5, Soluplus) and a surfactant (TPGS) were prepared using hotmelt process. The prepared ASDs were characterized using DSC, FTIR, and XRD. The aqueous solubility of the model drugs was determined using shake-flask method. Multiple linear regression was used to develop a predictive model to determine aqueous solubility using the molecular descriptors of the drug and polymer as predictor variables. The model was validated using Leave-One-Out Cross-Validation.

RESULTS

The ASDs' drug components were identified as amorphous via DSC and XRD Studies. There were no significant chemical interactions between the model drugs and the polymers based on FTIR studies. The ASDs showed a significant (p < 0.05) improvement in solubility, ranging from a 3-fold to 118-fold, compared with the pure drug. The developed empirical model predicted the solubility of the model drugs from the ASDs containing model polymer matrices with an accuracy greater than 80%.

CONCLUSION

The developed empirical model demonstrated robustness and predicted the aqueous solubility of model drugs from the ASDs of model polymer matrices with an accuracy greater than 80%.

Nanosized ethosomal dispersions for enhanced transdermal delivery of nebivolol using intradermal/transfollicular sustained reservoir: in vitro evaluation, confocal laser scanning microscopy, and in vivo pharmacokinetic studies

Nebivolol (NBV), a BCS class II anti-hypertensive drug, suffers from limited solubility and oral bioavailability. Nanosized ethosomes were adopted as an approach to solubilize and deliver NBV transdermally, as a substitute to oral route. Ethosomal dispersions were prepared employing thin film hydration method. Formulation variables were adjusted to obtain entrapment efficiency; EE > 50%, particle size; PS < 100 nm, zeta potential; ZP > ±25 mV, and polydispersity index; PDI < 0.5. The optimized ethosomal dispersion (OED) showed accepted EE 86.46 ± 0.15%, PS 73.50 ± 0.08 nm, ZP 33.75 ± 1.20 mV, and PDI 0.31 ± 0.07. It also showed enhanced cumulative amount of NBV permeated at 8 h (Q8) 71.26 ± 1.46% and 24 h (Q24) 98.18 ± 1.02%. TEM images denoted spherical vesicles with light colored lipid bi-layer and dark core. Confocal laser scanning microscopy showed deeply localized intradermal and transfollicular permeation of the fluorolabelled OED (FL-OED). Nanosized FL-OED (<100 nm) can permeate through hair follicles creating a drug reservoir for enhanced systemic absorption. OED formulated into transdermal patch (OED-TP1) exhibited accepted physicochemical properties including; thickness 0.14 ± 0.01 mm, folding endurance 151 ± 0.07, surface pH 5.80 ± 0.15, drug content 98.64 ± 2.01%, mucoadhesion 8534 ± 0.03, Q8 87.61 ± 0.11%, and Q24 99.22 ± 0.24%. In vivo pharmacokinetic studies showed significantly enhanced bioavailability of OED-TP1 by 7.9 folds compared to oral Nevilob® tablets (p = 0.0002). It could be concluded that OED-TP1 can be a promising lipid nanocarrier TDDS for NBV and an efficacious alternative route of administration for hypertensive patients suffering from dysphagia.

A Versatile Stability-indicating Liquid Chromatographic Method for the Simultaneous Determination of Atenolol, Hydrochlorothiazide and Chlorthalidone

Background:

Atenolol is a selective beta 1 blocker that can be used alone or in combination with hydrochlorothiazide or with chlorthalidone for the treatment of hypertension and prevention from a heart attack.

Objective:

The main target of this work was to improve modern, easy, accurate and selective liquid chromatographic method (RP-HPLC) for the determination of these drugs in the presence of their degradation products. These methods can be used as analytical gadgets in quality control laboratories for a routine examination.

Methods:

In this method, the separation was accomplished through an Inertsil® ODS-3V C18 column (250 mm x 4.6 mm, 5 μm), the mobile phase used was 25 mM aqueous potassium dihydrogen orthophosphate solution adjusted to pH 6.8 by using 0.1M sodium hydroxide and acetonitrile (77 : 23, v/v), the flow rate used was 1 ml/min and detection was achieved at 235 nm using UV.

Results:

All peaks were sharp and well separated, the retention times were atenolol degradation (ATN Deg.) 2.311 min, atenolol (ATN) 2.580 min, hydrochlorothiazide degradation (HCT Deg.) 5.890 min, hydrochlorothiazide (HCT) 7.016 min, chlorthalidone degradation CTD Deg 8.018 min and chlorthalidone (CTD) 14.972 min. Linearity was obtained and the range of concentrations was 20- 160 μg/ml for atenolol, 10-80 μg/ml for hydrochlorothiazide and 10-80 μg/ml for chlorthalidone. According to ICH guidelines, method validation was accomplished, these methods include linearity, accuracy, selectivity, precision and robustness.

Conclusion:

The optimized method demonstrated to be specific, robust and accurate for the quality control of the cited drugs in pharmaceutical dosage forms.

Chemometric-assisted spectrophotometric methods and high performance liquid chromatography for simultaneous determination of seven β-blockers in their pharmaceutical products: a comparative study

Chemometric-assisted spectrophotometric methods and high performance liquid chromatography (HPLC) were developed for the simultaneous determination of the seven most commonly prescribed β-blockers (atenolol, sotalol, metoprolol, bisoprolol, propranolol, carvedilol and nebivolol). Principal component regression PCR, partial least square PLS and PLS with previous wavelength selection by genetic algorithm (GA-PLS) were used for chemometric analysis of spectral data of these drugs. The compositions of the mixtures used in the calibration set were varied to cover the linearity ranges 0.7-10 μg ml(-1) for AT, 1-15 μg ml(-1) for ST, 1-15 μg ml(-1) for MT, 0.3-5 μg ml(-1) for BS, 0.1-3 μg ml(-1) for PR, 0.1-3 μg ml(-1) for CV and 0.7-5 μg ml(-1) for NB. The analytical performances of these chemometric methods were characterized by relative prediction errors and were compared with each other. GA-PLS showed superiority over the other applied multivariate methods due to the wavelength selection. A new gradient HPLC method had been developed using statistical experimental design. Optimum conditions of separation were determined with the aid of central composite design. The developed HPLC method was found to be linear in the range of 0.2-20 μg ml(-1) for AT, 0.2-20 μg ml(-1) for ST, 0.1-15 μg ml(-1) for MT, 0.1-15 μg ml(-1) for BS, 0.1-13 μg ml(-1) for PR, 0.1-13 μg ml(-1) for CV and 0.4-20 μg ml(-1) for NB. No significant difference between the results of the proposed GA-PLS and HPLC methods with respect to accuracy and precision. The proposed analytical methods did not show any interference of the excipients when applied to pharmaceutical products.