Design and production of 3D printed oral capsular devices for the modified release of urea in ruminants.

The use of 3D printing for the production of systems intended for oral delivery of diet supplements in the veterinary pharmacy constitutes an attractive technology that has remained unexplored. In this sense, this work studies the design and 3D printing of capsular devices that allow the modified release of urea, which is frequently used as a source of non-protein nitrogen in ruminants, but highly toxic if fast ingested. The devices were printed with combinations of polylactic acid (PLA, water-insoluble) and polyvinyl alcohol (PVA, water-soluble) in order to modulate the urea release through the different parts. The optimization of the designs as well as printing parameters such as extrusion temperature, printing speed, retraction distance and nozzle speed resulted critical to obtain successful capsular devices. In addition, the dissolution studies confirmed that the developed designs showed a controlled release of urea, especially the ones that presented internal partitions. Finally, Logistic and Weibull equations were the kinetic models that best fitted the experimental data corresponding to functions that describe S-shaped dissolution profiles. Overall, this work constitutes a proof of concept and provides the first steps in the development of 3D printed simple devices for the controlled release of supplements and drugs in veterinary pharmacy.

Characteristics of ectopic parathyroid glands in 145 cases of primary hyperparathyroidism.

OBJECTIVE: To determine the prevalence of primary hyperparathyroidism (PHPT) arising from ectopic parathyroid glands, to analyze the clinical, biochemical, and anatomic characteristics of such cases, and to compare these characteristics with those found in PHPT associated with orthotopic parathyroid glands. METHODS: We conducted a retrospective study of cases of PHPT evaluated and treated at a referral center. Differences between patients with orthotopic and ectopic parathyroid glands were analyzed statistically. RESULTS: During a recent 5-year period at our institution, 145 cases of PHPT were treated operatively by 3 experienced surgeons. An ectopic parathyroid location was detected in 13 cases (9%). Of the 13 ectopic glands, 4 (31%) were at the tracheoesophageal groove, 4 (31%) were intrathymic, 2 (15%) were intrathyroidal, and 1 each was located in the aortopulmonary window, the anterior (nonthymic) mediastinum, and the submaxillary region. Patients with PHPT attributable to ectopic adenomas had significantly higher serum calcium levels (12.6 ± 0.9 mg/dL versus 11.4 ± 1.2 mg/dL; P = .05) and larger tumors (25 ± 6.1 mm versus 19 ± 7.6 mm; P = .05) than did patients with orthotopic parathyroid glands. Moreover, hyperparathyroidism- related bone disease was significantly more frequent in patients with abnormal ectopic parathyroid glands than in those with orthotopic parathyroid glands (23% versus 1.5%, respectively; P = .04). CONCLUSION: In 9% of all cases of PHPT in our study, the condition was associated with ectopically located parathyroid glands. Such cases are usually characterized by larger parathyroid glands, higher serum calcium levels, and a higher frequency of severe bone disease.