Development and validation of analytical method by HPLC-DAD for determination of vasodilator active in pharmaceutical ophthalmic forms

The substance 4-Aminobenzamidine dihydrochloride (4-AD) is one of the degradation products of diminazene aceturate and has demonstrated antiglaucomatous potential. Glaucoma is the second leading cause of blindness worldwide; thus, new therapeutic alternatives must be studied, for example, the molecule 4-AD vehiculated into polymeric inserts for prolonged release. The present work aims to develop and validate an analytical method to quantify 4-AD in pharmaceutical ophthalmic forms. A HPLC was used with UV-Vis detector, at 290 ƞm and ACE® C18 column (125 × 4.6 mm, 5 µm), in which the mobile phase consists of phosphate buffer (pH 7.4) and triethylamine (30 mmol/L), under an isocratic flow of 1.0 mL/min. The retention time of 3.2 minutes was observed. The method was developed and validated in accordance with ANVISA recommendations and ICH guides. The linearity range was established between the concentrations 5 and 25 µg/mL (correlation coefficient r = 0.993). The accuracy, repeatability, and intermediate precision tests obtained a relative standard deviation less than or equal to 5%. In addition, the method was considered selective, exact. and robust, with pH being its critical factor. Therefore, the HPLC analysis method is robust and can be used to quantify 4-AD in pharmaceutical forms for ocular application.(AU)

Hyaluronic acid accelerates bone repair in human dental sockets: a randomized triple-blind clinical trial

Abstract This study evaluated the effects of hyaluronic acid (HA) on bone repair of human dental sockets. Thirty-two lower first premolars were extracted from 16 patients (2 per patient) for orthodontic reasons. Following the extractions, one socket was randomly filled with 1% HA gel, while the other was allowed to naturally fill with blood clot. After 30 and 90 days of surgery, patients underwent cone beam computed tomography. Five central orthoradial slices were captured from each socket. The gray intensity was measured in each image and results were reported as mean percentage of bone formation. The buccolingual alveolar ridge width was measured and dimensional changes were compared between the postoperative intervals. The pattern of alveolar trabecular bone was evaluated through the fractal dimension. Treated sockets showed a higher percentage of bone formation and fractal dimension values (58.17% and 1.098, respectively) compared with controls (48.97% and 1.074, respectively) in the 30-day postoperative period (p < 0.05). After 90 days, there was no significant difference between groups. Additionally, no significant difference was found between groups regarding the alveolar dimensions (p > 0.05). Use of 1% HA gel after tooth extraction accelerates bone repair in human dental sockets.