Minocycline hydrochloride

Upon admission to the hospital for treatment, the patients were given 15 mg pentazocine and 25 mg hydroxyzine hydrochloride subcutaneously as premedication. After local analgesia of the puncture site with 1% mepivacaine hydro- chloride, a 15- or 20-cm-long, 21-gauge PTC needle (Hakko, Japan) was passed into the cyst under real-time ultrasonic guidance with a 3.5-MHz or 5-MHz convex transducer (model SSD-650, Aloka, Japan). In most cases, a radiograph of the cyst was obtained after injection of contrast medium to ensure that there was no communication with the biliary duct or extravasation into the peritoneal cavity. After aspiration of as much cystic fluid as possible, minocycline hydrochloride (Lederle, Japan) was injected into all cysts through the same puncture needle. Minocycline hydrochloride was dissolved in saline at a concentration of 200 mg to 9 ml and mixed with 1 ml of 2% mepivacaine hydrochloride to control pain. The pH of this mixture was about 2.4. The quantity of minocycline hydrochloride injected at any one time varied from 100 to 600 mg/cyst, depending on its size. In short, 100 mg of minocycline hydrochloride was injected into hepatic cysts smaller than 5 cm in diameter, 200-400 mg was instilled into cysts measuring 5-10 cm, and 600 mg was used for cysts larger than 10 cm in diameter. Thereafter we performed the aspiration and injection of remaining cystic fluid including minocycline hydrochloride several times using a 20-ml syringe so that the minocycline hydrochloride came into contact with all surfaces of the cystic cavity. In eight hepatic cysts of five patients, a small volume of cystic fluid containing minocycline hydrochloride was aspirated in order to measure the fluid pH, and this was compared with the pH of the cystic fluid before the injection of minocycline hydrochloride.

No malignant cells were detected in the fluid of any patients, and the results of chemical analysis were similar to those previously reported. No cyst wall irregularities suggesting malignant tumour were found in any of the patients. Minor complications such as slight fever and pain were observed in 21 (12.8%) of the 164 minocycline-treated patients, while slight fever developed in 2 (10.0%) of the 20 control patients. Major complications such as haemorrhage and infection were not encountered in either group. Minocycline hydrochloride was detected in all serum and urine samples obtained after injection. The range of concentrations was wide, with the maximum value of 1.4 gg/ml in serum and 9.1 Bg/ml in urine (Table 2). Minocycline hydrochloride solutions ranged from pH 2.34 to pH 3.78, depending upon the volume of distilled water (pH 6.2) used as the diluent (Table 3).

Minocycline Hydrochloride is a broad-spectrum second generation semi-synthetic antibiotic belonging to the tetracycline family that is approved by the FDA (100-200 mg/day) for the treatment of acne vulgaris, some sexually transmitted diseases, and rheumatoid arthritis. Recently minocycline Hydrochloride was found to inhibit p38 MAPK activity, which contributes to apoptotic signal transduction and induces cell death, in animal models of Huntington’s disease (Chen et al., 2000), amyotrophic lateral sclerosis (Kim and Suh, 2009), Parkinson’s disease (Du et al., 2001), and other neurodegenerative diseases (Zuch et al., 2000; Barcia et al., 2003). As minocycline is effective for prevention and treatment of various dementias including Alzheimer’s disease and memory impairment (Dawson et al., 2003), our goal was to develop a pH-independent extended release matrix formulation for these applications.