This study aims to optimise the operating conditions for the supercritical fluid extraction (SFE) of toxic elements from fish oil. The SFE operating parameters of pressure, temperature, CO2 flow rate and extraction time were optimised using a central composite design (CCD) of response surface methodology (RSM). High coefficients of determination (R²) (0.897-0.988) for the predicted response surface models confirmed a satisfactory adjustment of the polynomial regression models with the operation conditions. The results showed that the linear and quadratic terms of pressure and temperature were the most significant (p < 0.05) variables affecting the overall responses. The optimum conditions for the simultaneous elimination of toxic elements comprised a pressure of 61 MPa, a temperature of 39.8ºC, a CO₂ flow rate of 3.7 ml min⁻¹ and an extraction time of 4 h. These optimised SFE conditions were able to produce fish oil with the contents of lead, cadmium, arsenic and mercury reduced by up to 98.3%, 96.1%, 94.9% and 93.7%, respectively. The fish oil extracted under the optimised SFE operating conditions was of good quality in terms of its fatty acid constituents.
INTRODUCTION: Glucocorticoid therapy is associated with an appreciable risk of bone loss leading to fractures that require expensive treatments. This study aimed to evaluate the cost-effectiveness of bisphosphonates for prevention of hip fracture in glucocorticoid-induced osteoporosis (GIOP) in Malaysia.
METHOD: Retrospective data were collected from GIOP patients referred to the Universiti Kebangsaan Malaysia Medical Centre. Fracture events and direct medical costs were compared between bisphosphonates and calcium/vitamin D combination.
RESULTS: Fracture events were reported in 28 out of 93 included patients, with hip and vertebral fractures representing 42.9% and 35.7%, respectively. Overall, the use of bisphosphonates could not be considered cost-effective for treatment of all GIOP patients. The presence of certain fracture risk factors was able to modify the cost-effectiveness of bisphosphonates. Bisphosphonates was considered cost-effective if started in patients more than 60 years old. However, the use of bisphosphonates was not cost-effective in GIOP patients with secondary osteoporosis. The incremental cost-effectiveness ratios (ICER) of bisphosphonates in patients with risk factors of previous fracture or rheumatoid arthritis were Malaysian Ringgits (MYR) 108 603.40 and MYR 25 699.21, respectively.
CONCLUSION: Fracture risk factors of age, previous fracture, rheumatoid arthritis and secondary osteoporosis may modify the cost-effectiveness outcomes of bisphosphonates. Bisphosphonates would be considered cost-effective in patients more than 60 years old as compared to calcium/vitamin D treatments. Further evaluation of the impact of fracture risk factors in larger populations would provide more precise information to better assist rational and economical use of anti-osteoporosis treatment in GIOP patients.