Nifedipine ratio

The in vitro release profile showed a burst release followed by controlled release. A more prolonged release can be achieved by increasing the PVA nifedipine ratio. 

GI absorption of many poorly soluble drugs depends on small intestinal transit, as demonstrated for ketoprofen, nifedipine, haloperidol, miconazole, and others. Small intestinal transit rate and transit time become important factors in drug absorption, particularly when the ratio of dose to solubility is high and dissolution rate is very slow or when the drug is... 

Buccoadhesive-controlled release tablets for delivery of nifedipine were prepared by direct compression of carboxymethyl cellulose (CMC) with carbomer (CP) and compared to those prepared with PVP, PVA, HPMC, and acacia by a modified tensiometry method in vitro. It was found that the adhesion force was significantly affected by the mixing ratio of CP CMC in the tablets. CMC is necessary for controlling the release rate, whereas CP is important in providing bioadhesion. The tablets containing 15% CMC and 35% CP were found to have optimum drug release rate and bioadhesion [81]. 

Fig. 3.19 ESR spectra of the 16-PC probe in total lipid (TL) liposomes. (A) control (B) TL-nifedipine (2 1 molar ratio) (C) TL-verapamil (2 1 molar ratio). Spectrum width 6 mT. Temperature 37°C. Arrows in spectrum (A) indicate 4max determination, arrows in spectrum (C) indicate 4min. (Reprinted from Fig. 2 of ref. 68 with permission from Elsevier Science.)...

The most used and validated probe drugs for C YP3 A phenotyping are midazolam and 14C-erythromycin (Watkins 1994). Alfentanyl, alprazolam, dapsone, dextromethorphan, lidocaine. nifedipine, omeprazole, quinine, verapamil have also been used but less frequently, and CYP3A specificity for some of them has been questioned. The endogenous 6(->-hydroxycortisol test (measurement of 6 3-hydroxycortisol cortisol ratio in urine) is only useful for detecting CYP3A induction, and may be influenced by renal CYP3 A activity. 

In a case-control surveillance of agranulocytosis and aplastic anemia conducted in the metropolitan area of Barcelona, where 178 cases of aplastic anemia were identified, nifedipine was associated with a significant relative risk of aplastic anemia, which translates into an absolute risk of 1.2 per patient-year. Among the 178 patients, 147 were interviewed and compared with 1295 controls. Six cases (4.1%) and 11 controls (0.8%) had been exposed to nifedipine during the window period, as aU of them had taken nifedipine for at least 7 months. The multivariate odds ratio was 4.6 (95% Cl = 1.5,15). AU six died within 5 months of diagnosis. The authors concluded that the risk of aplastic anemia associated with nifedipine is of a similar magnitude to that associated with chloramphenicol (1.7 per 100 000 patients) and that associated with phenylbutazone (2.2 per 100 000 patients) (21). 

FIGURE 40.15 Release profiles of nifedipine from double-layer tablets (25 mg as 5 mg nifedipine) consisting of nifedipine-HP-(3-CyD with 3% HCO-60 as fast-release portion (FRP) and nifedipine-HPC-M as slow-release portion (SRP) in various weight ratios (FRP SRP) in water at 37°C. O, 1 3 , 1 2 A, 1 1 A, 2 1 , 3 1. 

Nifedipine-PEG 4000 CO2 12-19 323-343 material Mass ratio (174) Sencar-Bozic... 

This reaction produces symmetrical dihydropyridines whose chemistry can be traced back to the late 1800s, biochemistry shortly thereafter, and pharmacology relevant to the present indication to the early 1970s. ( though its precursor nifedipine suffered from too short a half-life, if anything, 20 may now have too long a half-life, and T3 ratios can vary in the natural hormone. 

A diabetic patient taking glipizide and aspirin started taking nortriptyline, and, at the same time, his treatment with nifedipine was replaced by diltiazem 180 mg daily initially, raised to 240 mg daily after a week. Several changes in the nortriptyline dosage were made over a 4-week period because its plasma levels became unexpectedly high (the ratio of plasma nortriptyline to its dosage were approximately doubled). ... 

Fig. 5.1 MBP classification system (MCS). Circle stands for Easy drug and triangle stemds for Mfficult drug. DIP dipyridamole, DNZ danazol, FFB fenofibrate, GRI grisoeMvin, IDM indomethacin, 177 itraconazole, AIPX naproxen, AW nifedipine, Al/Lnilvadipine, ATP nitrendipine, PHE phenytoin, PMZ pimozide, PTX paclitaxel, KTZ ketoconazole. A-L, Roche in-house drugs. MBP preparation condition polymer HPMCAS pH 2 drug/polymer ratio = 3/7...

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