Benazepril hydrochloride

KKH Chan, A Buch, RD Glazer, VA John, WH Barr. Site-differential gastrointestinal absorption of benazepril hydrochloride in health volunteers. Pharmaceut Res 11 432-437, 1994. 

Belt-conveyor scales, 26 244—245 Belt filter press, 25 913 Belt saponification, in vinyl alcohol polymerization, 25 609-610 Benard instability, 11 764 Benazepril hydrochloride, molecular formula and structure, 5 149t Benchmark dose and margin-of-exposure method, 25 244... 

Brand Name Calan SR (verapamil) Norvasc (amlopidine) Lotrel (amlopidine and benazepril hydrochloride)... 

Benazepril hydrochloride is obtained as a white to off-white crystalline powder [3]. 

The solubility of benazepril hydrochloride is greater than 1 g in 10 mL of water, ethanol, and methanol. 

The X-ray powder diffraction pattern of benazepril hydrochloride was obtained using a Simons XRD-5000 diffractometer, and is shown in Figure 1. A summary of the observed scattering angles (degrees 2-6), the interplanar d-spacings (A), and the relative intensities (%) of the observed peaks of benazepril hydrochloride is found in Table 1. 

Benazepril melts at about 148-149° C, benazepril hydrochloride melts at about 189-190°C, and benazeprilat melts at about 270-272°C. 

The differential scanning calorimetry (DSC) thermogram of benazepril hydrochloride was obtained using a DuPont TA-9900 thermal analyzer attached to a DuPont Data unit. The thermogram shown in Figure 2 was obtained at a heating rate of 10°C/min, and was run from 100 to 220°C. The compound was found to melt at 190.0°C. 

Figure 1. X-ray powder diffraction pattern of benazepril hydrochloride.

The ultraviolet spectrum of benazepril hydrochloride (obtained at a concentration of 0.1 mg/mL in water), which is shown in Figure 3, was recorded using a Shimadzu model 1601 PC ultraviolet-visible spectrometer. The drug exhibited only one maximum at 238.5 nm, A[l%, 1 cm] = 198.7, and molar absorptivity = 9160. 

The infrared absorption spectrum of benazepril hydrochloride was obtained in a KBr pellet using a Perkin-Elmer infrared spectrophotometer. The infrared spectrum is shown in Figure 4, and the principal peaks were detected at 3435, 2980, 2680, 2467, 1739, 1674, 1524, 1390, 1211, 1003, 754, 702cm 1. The assignments of the major infrared absorption bands of benazepril hydrochloride are shown in Table 2. 

The proton NMR spectra of benazepril hydrochloride were obtained using a Bruker Advance System operating at 300, 400, or 500 MHz. 

Scattering Angles, d-Spacings, and Peak Relative Intensities from the X-Ray Powder Diffraction Pattern of Benazepril Hydrochloride... 

Figure 2. Differential scanning calorimetry thermogram of benazepril hydrochloride.

Figure 3. Ultraviolet absorption spectrum of benazepril hydrochloride (0.1 mg/mL,...

Standard Bruker Software was used to execute the recording of DEPT, COSY, and HETCOR spectra. The sample was dissolved in D20, and all resonance bands were referenced to the tetramethylsilane (TMS) internal standard. The H-NMR spectra of benazepril hydrochloride are shown in Figures 5-9. The H-NMR spectral assignments for benazepril hydrochloride are provided in Table 3. 

The carbon-13 NMR spectra of benazepril hydrochloride were obtained using a Bruker Advance Instrument operating at 75, 100, or 125 MHz. The sample was dissolved in D20, and tetramethylsilane (TMS) was added to function as the internal standard. The 13C-NMR spectra are shown in Figures 10-13, and the gradient HMQC NMR spectra are shown in Figures 14 and 15. The assignments for the observed resonance bands associated with the various carbons are provided in Table 4. 

---