Development and validation of RP-HPLC method for simultaneous determination of lamivudine, stavudine, and zidovudine in perfusate samples: Application to the Single-Pass Intestinal Perfusion (SPIP) studies

A reversed-phase high performance liquid chromatography (RP-HPLC) method with ultraviolet detection was developed and validated for the simultaneous quantification of antiretroviral drugs lamivudine (3TC), stavudine (d4T), and zidovudine (AZT) in perfusate samples obtained from the Single-Pass Intestinal Perfusion studies. The chromatographic analysis was performed using a Gemini C18 column and didanosine as internal standard (IS). The following parameters were considered for the validation procedure: system suitability, accuracy, precision, linearity and selectivity. The limits of detection were 0.32 µg/mL for 3TC, 0.11 µg/mL for d4T and 0.45 µg/mL for AZT and the limits of quantification were 1.06 µg/mL for 3TC, 0.38 µg/mL for d4T and 1.51 µg/mL for AZT. Repeatability and intermediate precision ranged from 1.05 to 1.31 and 1.50 to 1.87, respectively, and are expressed as percent of relative standard deviation (RSD). Based on these results, the developed and validated RP-HPLC method can be used for simultaneous determination of 3TC, d4T, and AZT in perfusate samples. Furthermore, this method is simple and adequate for measurements of the antiretroviral drugs in the same sample, since those compounds are mostly co-administered. Besides, this work can be used as an initial base for the development of similar methods in the same conditions presented in our study.

Analysis of Intestinal Absorption Characteristics of Matrine and Glycyrrhizic Acid / 中国药师

Objective:To investigate the absorption characteristics of matrine and glycyrrhizic acid in different intestinal segment and at various mass concentration,and explore the absorption changes of the combination of the two drugs.Methods:In situ single pass intestinal perfusion (SPIP) model was used,and the concentration changes of matrine and glycyrrhizic acid were determined by HPLC, and Kaand Peffwere calculated. Results:Matrine was absorbed in the whole of small intestine, and best in jejunum, and compared with the duodenum and ileum,the absorption had significant difference (P<0.05).The absorption at different mass concentrations had significant difference(P<0.05). The absorption of glycyrrhizic acid in small intestine was poor without significant differences in different intestinal segments and at various doses (P>0.05). After the combination of the two drugs, the absorption of matrine and glycyrrhizic acid had significant difference when compared with that of separated use(P<0.05). Conclusion:The absorption of ma-trine is dose-dependent,and with the dose increase,the absorption increases. Glycyrrhizic acid absorption does not change with mass concentration,and the absorption may be passive transport. The combination of the two drugs can improve the in vivo absorption of ma-trine and increase the concentration of glycyrrhizic acid in intestine.

Overall intestinal permeability of multiple components in lotus leaf by in situ single pass intestinal perfusion models / 中国中药杂志

To investigate the overall intestinal permeability of multiple components in lotus leaves and make clear the interaction in composition absorption process. Rat single-pass intestinal perfusion technique was used, and the results showed that the Peff values of nuciferine, demethylanuciferine, rutin, quercetin, kaempferol from lotus leaf were greater than 0.5×10⁻⁴ cm•s⁻¹. In the biopharmaceutics classification system (BCS) intestinal permeability property, these ingredients were high permeable components, while the hyperin was low permeable component. However, in the multi-component environment of the lotus leaf extract, component permeation was changed. Semi quantitative analysis of the unclear components showed that under the multi-component environment, four in seven components with relatively high contents had a Peff value less than 0.5×10⁻⁴ cm•s⁻¹, indicating these 4 components were of low permeability, while other 3 components were of high permeability. The results could be valuable to make clear the overall intestinal permeability of multiple components in lotus leaf, and lay a foundation for studying the mechanism of the lipid-lowering effect of lotus leaf.

Intestinal lymphatic transport of matrine from two self-nanoemulsifying drug delivery systems assessed by triple single pass intestinal perfusion approach in rats / 中国药学杂志

OBJECTIVE: To investigate the differences of two matrine (MA) self-nanoemulsifying drug delivery systems (SNEDDS) in intestinal lymphatic transport. METHODS: Triple single pass intestinal perfusion model (T-SPIP) was established to study the intestinal absorption kinetics of MA in different absorption segments of rats with chylomicron flow blocking approach using colchicine as the blocker. The concentration of MA in the perfustae was measured by HPLC. RESULTS: The two SNEDDSs had regular spherical surface and narrow particle size distribution. MA showed high Peff. The phospholipid complex formulation (MPC-SN) exhibited higher intestinal lymphatic transport especially in distal ileum, and it was influenced more significantly by the chylomicron flow blocker in distal ileum compared to in proximal jejunum and mid-small intestine. CONCLUSION: SNEDDS can improve the absorption of MA by intestinal lymphatic transport. MPC-SN might be easier to be absorbed via lymphatic transport because of its high lipophilicity and small particle size.