Poly-L-lysine Coated Oral Nanoemulsion for Combined Delivery of Insulin and C-Peptide.

An attempt of co-delivery of insulin and C-peptide enclosed in linseed oil globules has been made employing a protective coating of positively charged poly-L-lysine to manage diabetes-associated complications. Oral water in oil in water (w/o/w) nanoemulsion manufactured by double emulsification method showed good entrapment efficiency of 87.6 ± 7.48% for insulin and 73.4 ± 6.44% for C-peptide. The optimized uncoated nanoemulsion showed a mean globule size of 210.6 ± 9.87 nm with a good PDI of 0.145 ± 0.033 and -21.7 ± 4.5 mV ZP. The poly-L-lysine coating of the nanoemulsion resulted in the reversal of surface charge to positive i.e. 18.3 ± 2.7 mV due to the cationic nature of poly-L-lysine. In vitro drug release showed an initial burst of 15-20% release within 4 h followed by controlled release up to 24 h. The poly-L-lysine coated nanoemulsion showed an 8.28-fold higher uptake than fluorescein isothiocyanate (FITC) solution in HCT116 intestinal cell lines. In vivo studies confirmed that orally administered insulin and C-peptide bearing coated nanoemulsion has the potential to improve glycemic control confirmed by blood glucose level under 200 mg/dL for 12 h compared to that of subcutaneous administration of insulin. The formulation was found stable at 25 °C as well as 4°C for up to 3 months. These findings show a promising approach for delivering oral insulin along with C-peptide for effective glycemic control and management of complications associated with diabetes.

Development and validation of an LC-MS/MS method for simultaneous determination of piperaquine and 97-63, the active metabolite of CDRI 97-78, in rat plasma and its application in interaction study.

Piperaquine-dihydroartemisinin combination is the latest addition to the repertoire of ACTs recommended by the World Health Organization (WHO) for treatment of falciparum malaria. Due to the increasing resistance to artemisinin derivatives, CSIR-CDRI has developed a prospective short acting, trioxane antimalarial derivative, CDRI 97-78. In the present study, a liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the simultaneous quantification of piperaquine (PPQ) and 97-63, the active metabolite of CDRI 97-78 found in vivo, was developed and validated in 100 µL rat plasma using halofantrine as internal standard. PPQ and 97-63 were separated using acetonitrile:methanol (50:50, v/v) and ammonium formate buffer (10 mM, pH 4.5) in the ratio of 95:5(v/v) as mobile phase under isocratic conditions at a flow rate of 0.65 mL/min on Waters Atlantis C18 (4.6 × 50 mm, 5.0 µm) column. The extraction recoveries of PPQ and 97-63 ranged from 90.58 to 105.48%, while for the internal standard, it was 94.27%. The method was accurate and precise in the linearity range 3.9-250 ng/mL for both the analytes, with a correlation coefficient (r) of ≥ 0.998. The intra- and inter-day assay precision ranged from 2.91 to 8.45% and; intra- and inter-day assay accuracy was between 92.50 and 110.20% for both the analytes. The method was successfully applied to study the effect of oral co-administration of PPQ on the pharmacokinetics of CDRI 97-78 in Sprague-dawley rats and vice versa. The co-administration of CDRI 97-78 caused significant decrease in AUC0-∞ of PPQ from 31.52 ± 2.68 to 14.84 ± 4.33 h*µg/mL. However, co-administration of PPQ did not have any significant effect on the pharmacokinetics of CDRI 97-78.

No effect on pharmacokinetics of tamoxifen and 4-hydroxytamoxifen by multiple doses of red clover capsule in rats.

Tamoxifen is used in clinical practice for breast cancer patients and to prevent osteoporosis. Red clover (Trifolium pratense) preparations are consumed worldwide as dietary supplements for relieving postmenopausal symptoms. In the present study we investigated the possible herb-drug interaction between red clover and tamoxifen in rats. 15 days pre-treatment with red clover did not alter the tamoxifen and its active metabolite 4-hydroxytamoxifen pharmacokinetics significantly (p > 0.05). Therefore the therapeutic efficacy of the tamoxifen may not be compromised by the co-administration with red clover. Tamoxifen metabolism is primarily mediated by CYP2D6, CYP3A4 with minor contribution from CYP2C9, CYP2E1 and CYP1A2 isoforms. Although, red clover pre-treatment significantly (p < 0.05) decreased the mRNA expression and activity of CYP3a2, no effect on CYP2d4 and increased expression and activity of CYP2c11 could be the plausible reasons for lack of effect on tamoxifen and its metabolite pharmacokinetics in rats. CYP1a1 and CYP2b2 mRNA expression and activity were also significantly reduced by red clover. To extend the clinical utility of the present study, effect of red clover extract on major CYPs using human liver microsomes and HepG2 cell lines were also determined. Similar finding were observed in the human liver preparations as in rats.

Simultaneous determination of centchroman and tamoxifen along with their metabolites in rat plasma using LC-MS/MS.

AIM: Tamoxifen and centchroman are two non-steroidal, selective estrogen receptors modulators, intended for long term therapy in the woman. Because of their wide spread use, there is a possibility of co-prescription of these agents. MATERIALS & METHODS: We studied the probable pharmacokinetic interaction between these agents in breast cancer model rats. A simple, sensitive and rapid LC-ESI-MS/MS method was developed and validated for the simultaneous determination of tamoxifen, centchroman and their active metabolites. RESULTS: The method was linear over a range of 0.2-200 ng/ml. All validation parameters met the acceptance criteria according to regulatory guidelines. CONCLUSION: LC-MS/MS method for determination of tamoxifen, centchroman and their metabolites was developed and validated. Results show the potential of drug-drug interaction upon co-administration these two marketed drugs.