Downstream processing from melt granulation towards tablets: In-depth analysis of a continuous twin-screw melt granulation process using polymeric binders.

The concept of twin-screw melt granulation (TSMG) has steadily (re)-gained interest in pharmaceutical formulation development as an intermediate step during tablet manufacturing. However, to be considered as a viable processing option for solid oral dosage forms there is a need to understand all critical sources of variability which could affect this granulation technique. The purpose of this study was to provide an in-depth analysis of the continuous TSMG process in order to expose the critical process parameters (CPP) and elucidate the impact of process and formulation parameters on the critical quality attributes (CQA) of granules and tablets during continuous TSMG. A first part of the study dealt with the screening of various amorphous polymers as binder for producing high-dosed melt granules of two model drug (i.e. acetaminophen and hydrochlorothiazide). The second part of this study described a quality-by-design (QbD) approach for melt granulation of hydrochlorothiazide in order to thoroughly evaluate TSMG, milling and tableting stage of the continuous TSMG line. Using amorphous polymeric binders resulted in melt granules with high milling efficiency due to their brittle behaviour without producing excessive amounts of fines, providing high granule yields with low friability. Therefore, it makes them extremely suitable for further downstream processing. One of the most important CPP during TSMG with polymeric binders was the granulation-torque, which - in case of polymers with high Tg - increased during longer granulation runs to critical levels endangering the continuous process flow. However, by optimizing both screw speed and throughput or changing to polymeric binders with lower Tg it was possible to significantly reduce this risk. This research paper highlighted that TSMG must be considered as a viable option during formulation development of solid oral dosage forms based on the robustness of the CQA of both melt granules and tablets.

Association of obstructive sleep apnea with arterial stiffness and nondipping blood pressure in patients with hypertension.

Whether sex influences the association of obstructive sleep apnea (OSA) with markers of cardiovascular risk in patients with hypertension is unknown. In this study, 95 hypertensive participants underwent carotid-femoral pulse wave velocity, 24-hour ambulatory blood pressure monitoring, echocardiogram, and polysomnography after a 30-day standardized treatment with hydrochlorothiazide plus enalapril or losartan. OSA was present in 52 patients. Compared with non-OSA patients, pulse wave velocity values were higher in the OSA group (men: 11.1±2.2 vs 12.7±2.4 m/s, P=.04; women: 11.8±2.4 vs 13.2±2.2 m/s, P=.03). The proportion of diastolic dysfunction was significant in men and women with OSA. Compared with non-OSA patients, nondipping systolic blood pressure in OSA was higher in men (14.3% vs 46.4%) and in women (41.4% vs 65.2%). OSA was independently associated with pulse wave velocity (ß=1.050; P=.025) and nondipping systolic blood pressure (odds ratio, 3.03; 95% confidence interval, 1.08-8.55; P=.035) in the regression analysis. In conclusion, OSA is independently associated with arterial stiffness and nondipping blood pressure in patients with hypertension regardless of sex.

Do placebo based validation standards mimic real batch products behaviour? Case studies.

Analytical methods validation is a mandatory step to evaluate the ability of developed methods to provide accurate results for their routine application. Validation usually involves validation standards or quality control samples that are prepared in placebo or reconstituted matrix made of a mixture of all the ingredients composing the drug product except the active substance or the analyte under investigation. However, one of the main concerns that can be made with this approach is that it may lack an important source of variability that come from the manufacturing process. The question that remains at the end of the validation step is about the transferability of the quantitative performance from validation standards to real authentic drug product samples. In this work, this topic is investigated through three case studies. Three analytical methods were validated using the commonly spiked placebo validation standards at several concentration levels as well as using samples coming from authentic batch samples (tablets and syrups). The results showed that, depending on the type of response function used as calibration curve, there were various degrees of differences in the results accuracy obtained with the two types of samples. Nonetheless the use of spiked placebo validation standards was showed to mimic relatively well the quantitative behaviour of the analytical methods with authentic batch samples. Adding these authentic batch samples into the validation design may help the analyst to select and confirm the most fit for purpose calibration curve and thus increase the accuracy and reliability of the results generated by the method in routine application.

Simultaneous determination of eight active components in Chinese medicine 'JiangYaBiFeng' tablet by HPLC coupled with diode array detection.

An effective, accurate and reliable method was developed for the simultaneous separation and determination of eight active components (baicalin, baicalein, sophoricoside, rutin, quercetin, genistein, pargyline and hydrochlorothiazide) in Chinese medicine 'JiangYaBiFeng' tablet (JYBF tablet) by high-performance liquid chromatography (HPLC) coupled with diode array detection (DAD). Due to the different UV characteristic of these components, different wavelengths were selected for analysis of different analytes, such as 210nm for pargyline, 256nm for sophoricoside, rutin, quercetin and genistein, and 280nm for baicalin, baicalein and hydrochlorothiazide. Excellent linear behaviors over the investigated concentration ranges were observed with the values of R(2) higher than 0.9990 for all analytes. The recovery rates and relative standard deviation (RSD) for all analytes at three different concentrations were 94.9-104.7% and 1.23-3.00%, respectively. The validated method was successfully applied to the simultaneously determination of these active components in 'JiangYaBiFeng' tablet from different production batches, indicating that the proposed method in this paper was particularly suitable for the routine analysis of JYBF tablet and its quality control.

Lisinopril and lisinopril/hydrochlorothiazide preparations on the Belgian market: a comparative study.

Preparations containing lisinopril and the combination lisinopril/hydrochlorothiazide, and formulated as tablets were evaluated with different tests, including in vitro dissolution, assay and content uniformity, and determination of related compounds. The analytical methods were previously validated according to international guidelines. All examined products complied with the postulated requirements.

Doxazosin GITS versus hydrochlorothiazide as add-on therapy in patients with uncontrolled hypertension.

The objective of this prospective, randomized, open-label, parallel-arm comparative study, with a 4-month follow-up, was to assess the antihypertensive efficacy, tolerability and metabolic safety of doxazosin GITS (gastrointestinal therapeutic system) 4-8 mg/day vs hydrochlorothiazide (HCTZ) 12.5-25 mg/day as add-on therapy in patients not controlled with monotherapy with other drugs. Ninety-eight patients completed the study (mean age 57.4 +/- 15 years, 53% female). Mean systolic/diastolic blood pressure reduction was 8.2/4.5 mmHg in the HCTZ group and 8.9/5.0 mmHg in the doxazosin GITS group, and a strict blood pressure control was achieved in 79% and 83% of the patients, respectively. The incidence rates of adverse events were low and similar in both groups. However, metabolic differences were seen between the groups, doxazosin GITS vs HCTZ, respectively: total cholesterol (mg/dl) 210 +/- 53 vs 231 +/- 62 (p < 0.05), low-density lipoprotein (LDL) cholesterol (mg/dl) 139 +/- 40 vs 161 +/- 57 (p < 0.01), high-density lipoprotein (HDL) cholesterol (mg/dl) 58 +/- 16 vs 48 +/- 13 (p < 0.01), HDL/total cholesterol ratio 27.6 +/- 8 vs 21.2 +/- 7 (p < 0.001), plasma uric acid (mg/dl) 5.3 +/- 2.6 vs 6.8 +/- 3.1 (p < 0.05) and serum potassium (mEq/l) 4.1 +/- 1.3 vs. 3.7 +/- 1.2 (p < 0.01). In conclusion, doxazosin GITS has a tolerability and efficacy profile similar to low doses of thiazide diuretics, with a better evolution of metabolic and electrolyte parameters. Therefore, in patients not controlled with monotherapy, doxazosin GITS can be considered an alternative to the addition of thiazide diuretics.

Spectrophotometric quantitative determination of cilazapril and hydrochlorothiazide in tablets by chemometric methods.

Four chemometric methods were applied to simultaneous determination of cilazapril and hydrochlorothiazide in tablets. Classical least-square (CLS), inverse least-square (ILS), principal component regression (PCR) and partial least-squares (PLS) methods do not need any priori graphical treatment of the overlapping spectra of two drugs in a mixture. For all chemometric calibrations a concentration set of the random mixture consisting of the two drugs in 0.1 M HCI and methanol (1:1) was prepared. The absorbance data in the UV-Vis spectra were measured for the 15 wavelength points (from 222 to 276 nm) in the spectral region 210-290 nm considering the intervals of deltalambda = 4 nm. The calibration of the investigated methods involves only absorbance and concentration data matrices. The developed calibrations were tested for the synthetic mixtures consisting of two drugs and using the Maple V software the chemometric calculations were performed. The results of the methods were compared each other as well as with HPLC method and a good agreement was found.

Simultaneous determination of losartan and hydrochlorothiazide in combined dosage forms by first-derivative spectroscopy and high-performance thin-layer chromatography.

Losartan (LST) is the first orally active nonpeptide angiotensin-II receptor antagonist with an improved safety and tolerability profile. It is prescribed alone or in combination with hydrochlorothiazide (HCTZ) for the treatment of moderate-to-severe hypertension. This paper describes the development of 2 methods that use different techniques, first-derivative spectroscopy and high-performance thin-layer chromatography (HPTLC), to determine LST and HCTZ in the presence of each other. LST and HCTZ in combined preparations were quantitated by using the first-derivative responses at 271.6 nm for LST and 335.0 nm for HCTZ in spectra of their solutions in water. The linearity ranges are 30-70 microg/mL for LST and 7.5-17.5 microg/mL for HCTZ with correlation coefficients of 0.9998 and 0.9997, respectively. In the HPTLC method, a mobile phase of chloroform-methanol-acetone-formic acid (7.5 + 1.5 + 0.5 + 0.03, v/v) and a prewashed Silica Gel G60 F254 TLC plate as the stationary phase were used to resolve LST and HCTZ in a mixture. Two well-separated and sharp peaks for LST and HCTZ were obtained at Rf values of 0.61+/-0.02 and 0.41+/-0.02, respectively. LST and HCTZ were quantitated at 254.0 nm. The linearity ranges obtained for the HPTLC method are 400-1200 and 100-300 ng/spot with corresponding correlation coefficients of 0.9944 and 0.9979, for LST and HCTZ, respectively. Both methods were validated, and the results were compared statistically. They were found to be accurate, specific, and reproducible. The methods were successfully applied to the estimation of LST and HCTZ in combined tablet formulations.

Perindopril plus nifedipine versus perindopril plus hydrochlorothiazide in mild to severe hypertension: a double-blind multicentre study. The Multicentre Study Group on Treatment Association with Perindopril.

Thiazide diuretics are considered as the choice drug to combine with ACE inhibitors for the treatment of hypertension. However, there is much evidence showing that the combination of ACE inhibitors with a calcium channel blocker is effective and safe. We compared the safety and efficacy of perindopril 8 mg once daily plus nifedipine SR 10 mg twice daily with perindopril 8 mg once daily plus hydrochlorothiazide (HCTZ) 12.5 mg once daily in a two phase three month study. After a one month placebo run-in period, patients whose DBP averaged 95-125 mmHg received perindopril 4 mg once daily for the first open phase (n = 524). After one month those whose DBP remained > 90 mmHg were prescribed perindopril 8 mg once daily for a second month. Among them, those whose DBP were still > 90 mmHg entered the second phase for one month, in a double-blind fashion. Fifty-three patients received HCTZ (BP: 161.2/99.2 +/- 2.0/0.9 mmHg), 57 received nifedipine (BP: 161.4/98.7 +/- 2.2/0.7 mmHg). Five patients withdrew due to side-effects, three patients in the perindopril plus nifedipine group and two in the perindopril plus HCTZ group. After one month there was a significant drop in BP (P < 0.01) in both groups: perindopril plus HCTZ (-13.9/-11.9 mmHg) and perindopril plus nifedipine (-12.1/-10.8 mmHg). Heart rate was not significantly modified: perindopril plus HCTZ (-1.30 beats/min), perindopril plus nifedipine (+0.54 beats/min). There were no significant difference between the two combinations for BP reduction and heart rate. The incidence of adverse experiences was similar in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of the efficacy and metabolic effects of nicardipine and hydrochlorothiazide in hypertensive black men and women.

A double-blind, randomised, parallel study compared the BP and metabolic responses in black hypertensive patients following monotherapy with nicardipine or hydrochlorothiazide (HCTZ). Following a single-blind placebo wash-out period of 1-4 weeks, the study drug, nicardipine 20-40 mg three times daily or HCTZ 25-100 mg four times daily, was administered in a double-blind fashion for 12 weeks. Doses were titrated to control sitting DBP (< or = 90 mmHg). Both drugs were effective in reducing sitting SBP and DBP as compared with baseline values (nicardipine: 152.5 +/- 1.6/102.0 +/- 0.6, HCTZ: 152.5 +/- 1.5/101.4 +/- 0.5 mmHg). DBP responses (reduction from baseline; nicardipine: -10.9, HCTZ: -12.7 mmHg), and the percentage of patients achieving a response < or = 90 mmHg (nicardipine: 54%, HCTZ: 63%) to the two drugs were similar. Although SBPs at baseline and endpoint (137.3 +/- 1.6 on nicardipine and 132.1 +/- 1.4 mmHg on HCTZ), and the percentage of patients achieving a response < or = 140 mmHg (nicardipine: 70%, HCTZ: 79%), were comparable between the two treatments, the SBP reduction with HCTZ was statistically greater (P = 0.026). A comparison of the metabolic responses in the two treatment groups showed significant differences. Nicardipine caused no significant changes in blood chemistry, whereas HCTZ caused statistically significant decreases (P < 0.001) in sodium and potassium and increases (P < or = 0.01) in glucose, BUN, creatinine, uric acid, cholesterol and LDL compared with baseline. In 12.7% of the patients in the HCTZ group, serum potassium dropped to levels < 3.5 meq/l, which occurred in only 1.4% of the patients who used nicardipine.(ABSTRACT TRUNCATED AT 250 WORDS)

MIDAS, the Multicenter Isradipine/Diuretic Atherosclerosis Study. Design features and baseline data.

The Multicenter Isradipine/Diuretic Atherosclerosis Study (MIDAS) is a randomized, double-blind, active-control trial to compare the effectiveness of two treatment regimens for the control of hypertension in reducing the rate of progression of early extracranial carotid artery atherosclerosis in hypertensive patients. The two double-blind treatment regimens are 2.5 or 5 mg isradipine twice daily and 12.5 mg or 25 mg hydrochlorothiazide twice daily. Patients whose blood pressure is not controlled with either of these regimens will receive, in addition to the highest tolerated dose of the blinded drug, 2.5 to 10 mg open-label enalapril twice daily. The MIDAS study has enrolled 883 patients to treatment with either isradipine or hydrochlorothiazide. Inclusion criteria included men and women over the age of 40 years, the presence of an atherosclerotic lesion in the extracranial carotid artery demonstrated on B-mode ultrasound scanning (maximum thickness between 1.3 and 3.5 mm), an average sitting diastolic blood pressure between 90 and 115 mm Hg, and low-density lipoprotein levels between 130 and 189 mg/dL. An assessment of each patient's blood pressure and any side effects is made every three months; a B-mode ultrasound examination of the carotid arteries was performed at baseline and every six months thereafter; an electrocardiogram was carried out at baseline and once a year thereafter; and a brief quality-of-life assessment was made at baseline and every year thereafter.