Study on Adsorption and Sustained Release of Eucommia ulmoides Oliv. Leaf Extracts on Activated Carbon.

BACKGROUND: Due to its excellent adsorption capability, activated carbon(AC) has also been employed as a drug carrier. However, applications of the AC carrier in traditional Chinese medicine (TCM) have been rare. We selected the Eucommia ulmoides leaf extract as the drug of choice and AC as its carrier, to investigate the adsorption and sustained release behavior of the Eucommia ulmoides leaf extract on the AC. METHODS: AC was employed in this study as the sustained release carrier and its capability for adsorption and sustained release of Eucommia ulmoides leaf extracts was systematically investigated. Acid or alkali modified AC was assessed for its ability to absorb and sustain release of Eucommia ulmoides leaf extracts according to a variety of adsorption/release rate and composition. RESULTS: Results demonstrated that the adsorption rate for the differently modified AC reached above 80 %, whereas the adsorption of Eucommia ulmoides leaf extracts on the AC was selective. The composition of the sustained release liquid, which was treated by the acid modified AC, was almost similar to the original extract. The acid modified AC was therefore taken as an optimal carrier that can be used for Eucommia ulmoides leaf extracts sustained release. CONCLUSION: The synchronous release and absorption of different ingredients in the active ingredient release process ensures the global and cooperative effect with sustained and less toxic advantages. The ideal synchronous release is that the absorbed component proportion is consistent with its release. The acid modified AC was therefore taken as the optimal carrier that can be used for Eucommia ulmoides leaf extracts sustained release.

[Effect of mean arterial pressure on arterial to end-tidal CO2partial pressure difference during one-lung ventilation].

OBJECTIVE: To study the effect of different mean arterial pressures (MAP) on arterial to end-tidal CO2partial pressure difference [(Pa-et)CO2] and the intrapulmonary shunt (Qs/Qt) in patients undergoing thoracic surgery during one-lung ventilation (OLV). METHODS: Forty-two patients undergoing right-sided pulmonary lobectomy were allocated into group A with fluctuation of MAP (at 20 min after OLV) within ± 10% of the baseline (n=22) and group B with lowered MAP by 30% of the baseline (n=20). Arterial and venous blood gas analyses were recorded to calculate [(Pa-et)CO2] and Qs/Qt at 20 min after induction with two-lung ventilation (T1), 20 min after OLV (T2), 30 min after recovery of normal blood pressure (T3), and 20 min after recovery of two-lung ventilation (T4). RESULTS: PetCO2and PaCO2were well correlated during two-lung ventilation and OLV in group A (P<0.05). In group B, [(Pa-et)CO2] at T2was significantly higher than that in group A, but PetCO2was still correlated with PaCO2(P<0.05). Qs/Qt increased more obviously in group B than in group A in T2(P<0.05). Bo obvious correlation was found between the [(Pa-et)CO2] and Qs/Qt during OLV. CONCLUSION: PetCO2reflects the dynamic changes of PaCO2under normal blood pressure during OLV. In the hypotension period, when [(Pa-et)CO2] increases and the correlation coefficient between PetCO2and PaCO2lowers, PetCO2may not accurately reflect the changes of PaCO2and blood gas analysis is warranted.