Milind Padki - Academia.edu (original) (raw)

Papers by Milind Padki

Research paper thumbnail of Targeting Aging with Metformin (TAME)

Research paper thumbnail of Targeting small unilamellar liposomes to hepatic parenchymal cells by dose effect

PubMed, Feb 1, 1989

A major research goal of liposome pharmacology is the selective delivery of drugs to target cell ... more A major research goal of liposome pharmacology is the selective delivery of drugs to target cell populations while minimizing extraction by phagocytic macrophages and blood monocytes of the reticuloendothelial system. The liver is an ideal organ for studying targeting strategies using a variety of liposomes, inasmuch as its discontinuous capillaries have fenestrae through which liposomes less than 0.2 microns in diameter may escape into the extravascular space. In a previous kinetic study, we proposed that the hepatic uptake of small unilamellar vesicles (SUV) in mice was compatible with a model of uptake involving dual, parallel pathways. One is a saturable, phagocytic pathway of uptake mediated by Kupffer cells, the other is a nonsaturable, pinocytotic pathway of uptake mediated by parenchymal cells, favoring the latter pathway at high liposomal dose (Beaumier et al., 1983). In the present study, we demonstrated by the techniques of liver cells fractionation that the uptake of either the bovine brain sphingomyelin/cholesterol (2:1; mole/mole) SUV or distearoyl phosphatidylcholine/cholesterol (2:1; mole/mole) SUV by hepatic parenchymal cells was enhanced markedly by increasing the amount of injected dose of SUV. As high as 85 to 90% of the total liver dose can be attributed to the uptake of SUV by the hepatic parenchymal cells alone, when the injected dose reaches at or above 7.5 to 10 micrograms of lipid per g b.wt. The dose effect on the uptake of liposomes by hepatocytes appears to be a general phenomenon of neutral SUV. Our data suggested that blockade by dose permits a feasible approach to target SUV to hepatic parenchymal cells.

Research paper thumbnail of Uptake of small liposomes by non-reticuloendothelial tissues

Biochimica Et Biophysica Acta - Biomembranes, Jul 1, 1987

The distribution of liposomes within the intravascular space and the extent to which they escape ... more The distribution of liposomes within the intravascular space and the extent to which they escape into extravascular space strongly impact on the application of lipid vesicles as a carrier for pharmacologically active agents. The present study investigates how intact small unilamellar vesicles (SUV) may be taken up by different tissues after intravenous injection into mice, using various types of SUV with different entrapped markers, lipid composition, size, doses of liposomal llpids and stability in the blood. Our focus was specifically on sphingomyelin (or distearoyl phosphatidylcholine)/cholesteroi (2:1, mol/mol) SUV, which are known to be stable in the blood circulation. Our results indicated that, in addition to the reticuioendothelial tissues, intact SUV were taken up in several other parts of the body, including intestine, skin, carcass and legs. It appears that the accumulation of SUV in the intestine and the skin increases with time post-injection. Furthermore, from the kinetic data, the process of uptake of SUV by the skin and intestine is compatible with a non-saturable pathway, which follows first-order kinetics. This suggests that the cells involved in the uptake of SUV in the intestine and skin are not phagocytic cells, which are normally saturable.

Research paper thumbnail of Liposome-mediated functional targeting of prednisolone

The Indian journal of medical research, 1986

Research paper thumbnail of The Cholesterol Bonded Phase as a Separation Medium in High Performance Liquid Chromatography. Evaluation of Properties and Applications

Journal of Chromatography A, 2003

An extensive survey of the properties and separation capabilities of a cholesterol bonded phase i... more An extensive survey of the properties and separation capabilities of a cholesterol bonded phase is reported. The intermediate hydrophobic / hydrophilic properties of the bonded cholesterol material allows this stationary phase to be used for both reversed-phase and aqueous normal-phase separations. Interesting high selectivity is reported for the structural isomers of some antibiotics. The cholesterol bonded material does not display ''phase collapse'' in high aqueous content mobile phases. Variable temperature studies demonstrate that substantial structural changes of the bonded moiety occur that might be used to control selectivity. Finally, separation of some enantiomers of compounds with a variety of chemical structures is reported under reversed-phase conditions indicating that the cholesterol material may be chiral stationary phase with a broad range of applicability.

Research paper thumbnail of Targeting Aging with Metformin (TAME)

Encyclopedia of Gerontology and Population Aging

Research paper thumbnail of Uptake of small liposomes by non-reticuloendothelial tissues

… et Biophysica Acta (BBA …, 1987

The distribution of liposomes within the intravascular space and the extent to which they escape ... more The distribution of liposomes within the intravascular space and the extent to which they escape into extravascular space strongly impact on the application of lipid vesicles as a carrier for pharmacologically active agents. The present study investigates how intact small unilamellar vesicles (SUV) ...

Research paper thumbnail of Cholesterol bonded phase as a separation medium in liquid chromatography

Journal of Chromatography A, 2003

An extensive survey of the properties and separation capabilities of a cholesterol bonded phase i... more An extensive survey of the properties and separation capabilities of a cholesterol bonded phase is reported. The intermediate hydrophobic/hydrophilic properties of the bonded cholesterol material allows this stationary phase to be used for both reversed-phase and aqueous normal-phase separations. Interesting high selectivity is reported for the structural isomers of some antibiotics. The cholesterol bonded material does not display “phase collapse” in high aqueous content mobile phases. Variable temperature studies demonstrate that substantial structural changes of the bonded moiety occur that might be used to control selectivity. Finally, separation of some enantiomers of compounds with a variety of chemical structures is reported under reversed-phase conditions indicating that the cholesterol material may be chiral stationary phase with a broad range of applicability.

Research paper thumbnail of Targeting Aging with Metformin (TAME)

Research paper thumbnail of Targeting small unilamellar liposomes to hepatic parenchymal cells by dose effect

PubMed, Feb 1, 1989

A major research goal of liposome pharmacology is the selective delivery of drugs to target cell ... more A major research goal of liposome pharmacology is the selective delivery of drugs to target cell populations while minimizing extraction by phagocytic macrophages and blood monocytes of the reticuloendothelial system. The liver is an ideal organ for studying targeting strategies using a variety of liposomes, inasmuch as its discontinuous capillaries have fenestrae through which liposomes less than 0.2 microns in diameter may escape into the extravascular space. In a previous kinetic study, we proposed that the hepatic uptake of small unilamellar vesicles (SUV) in mice was compatible with a model of uptake involving dual, parallel pathways. One is a saturable, phagocytic pathway of uptake mediated by Kupffer cells, the other is a nonsaturable, pinocytotic pathway of uptake mediated by parenchymal cells, favoring the latter pathway at high liposomal dose (Beaumier et al., 1983). In the present study, we demonstrated by the techniques of liver cells fractionation that the uptake of either the bovine brain sphingomyelin/cholesterol (2:1; mole/mole) SUV or distearoyl phosphatidylcholine/cholesterol (2:1; mole/mole) SUV by hepatic parenchymal cells was enhanced markedly by increasing the amount of injected dose of SUV. As high as 85 to 90% of the total liver dose can be attributed to the uptake of SUV by the hepatic parenchymal cells alone, when the injected dose reaches at or above 7.5 to 10 micrograms of lipid per g b.wt. The dose effect on the uptake of liposomes by hepatocytes appears to be a general phenomenon of neutral SUV. Our data suggested that blockade by dose permits a feasible approach to target SUV to hepatic parenchymal cells.

Research paper thumbnail of Uptake of small liposomes by non-reticuloendothelial tissues

Biochimica Et Biophysica Acta - Biomembranes, Jul 1, 1987

The distribution of liposomes within the intravascular space and the extent to which they escape ... more The distribution of liposomes within the intravascular space and the extent to which they escape into extravascular space strongly impact on the application of lipid vesicles as a carrier for pharmacologically active agents. The present study investigates how intact small unilamellar vesicles (SUV) may be taken up by different tissues after intravenous injection into mice, using various types of SUV with different entrapped markers, lipid composition, size, doses of liposomal llpids and stability in the blood. Our focus was specifically on sphingomyelin (or distearoyl phosphatidylcholine)/cholesteroi (2:1, mol/mol) SUV, which are known to be stable in the blood circulation. Our results indicated that, in addition to the reticuioendothelial tissues, intact SUV were taken up in several other parts of the body, including intestine, skin, carcass and legs. It appears that the accumulation of SUV in the intestine and the skin increases with time post-injection. Furthermore, from the kinetic data, the process of uptake of SUV by the skin and intestine is compatible with a non-saturable pathway, which follows first-order kinetics. This suggests that the cells involved in the uptake of SUV in the intestine and skin are not phagocytic cells, which are normally saturable.

Research paper thumbnail of Liposome-mediated functional targeting of prednisolone

The Indian journal of medical research, 1986

Research paper thumbnail of The Cholesterol Bonded Phase as a Separation Medium in High Performance Liquid Chromatography. Evaluation of Properties and Applications

Journal of Chromatography A, 2003

An extensive survey of the properties and separation capabilities of a cholesterol bonded phase i... more An extensive survey of the properties and separation capabilities of a cholesterol bonded phase is reported. The intermediate hydrophobic / hydrophilic properties of the bonded cholesterol material allows this stationary phase to be used for both reversed-phase and aqueous normal-phase separations. Interesting high selectivity is reported for the structural isomers of some antibiotics. The cholesterol bonded material does not display ''phase collapse'' in high aqueous content mobile phases. Variable temperature studies demonstrate that substantial structural changes of the bonded moiety occur that might be used to control selectivity. Finally, separation of some enantiomers of compounds with a variety of chemical structures is reported under reversed-phase conditions indicating that the cholesterol material may be chiral stationary phase with a broad range of applicability.

Research paper thumbnail of Targeting Aging with Metformin (TAME)

Encyclopedia of Gerontology and Population Aging

Research paper thumbnail of Uptake of small liposomes by non-reticuloendothelial tissues

… et Biophysica Acta (BBA …, 1987

The distribution of liposomes within the intravascular space and the extent to which they escape ... more The distribution of liposomes within the intravascular space and the extent to which they escape into extravascular space strongly impact on the application of lipid vesicles as a carrier for pharmacologically active agents. The present study investigates how intact small unilamellar vesicles (SUV) ...

Research paper thumbnail of Cholesterol bonded phase as a separation medium in liquid chromatography

Journal of Chromatography A, 2003

An extensive survey of the properties and separation capabilities of a cholesterol bonded phase i... more An extensive survey of the properties and separation capabilities of a cholesterol bonded phase is reported. The intermediate hydrophobic/hydrophilic properties of the bonded cholesterol material allows this stationary phase to be used for both reversed-phase and aqueous normal-phase separations. Interesting high selectivity is reported for the structural isomers of some antibiotics. The cholesterol bonded material does not display “phase collapse” in high aqueous content mobile phases. Variable temperature studies demonstrate that substantial structural changes of the bonded moiety occur that might be used to control selectivity. Finally, separation of some enantiomers of compounds with a variety of chemical structures is reported under reversed-phase conditions indicating that the cholesterol material may be chiral stationary phase with a broad range of applicability.