abdus samad - Academia.edu (original) (raw)

Papers by abdus samad

Current Drug Delivery, 2007

The discovery of liposome or lipid vesicle emerged from self forming enclosed lipid bi-layer upon... more The discovery of liposome or lipid vesicle emerged from self forming enclosed lipid bi-layer upon hydration; liposome drug delivery systems have played a significant role in formulation of potent drug to improve therapeutics. Recently the liposome formulations are targeted to reduce toxicity and increase accumulation at the target site. There are several new methods of liposome preparation based on lipid drug interaction and liposome disposition mechanism including the inhibition of rapid clearance of liposome by controlling particle size, charge and surface hydration. Most clinical applications of liposomal drug delivery are targeting to tissue with or without expression of target recognition molecules on lipid membrane. The liposomes are characterized with respect to physical, chemical and biological parameters. The sizing of liposome is also critical parameter which helps characterize the liposome which is usually performed by sequential extrusion at relatively low pressure through polycarbonate membrane (PCM). This mode of drug delivery lends more safety and efficacy to administration of several classes of drugs like antiviral, antifungal, antimicrobial, vaccines, anti-tubercular drugs and gene therapeutics. Present applications of the liposomes are in the immunology, dermatology, vaccine adjuvant, eye disorders, brain targeting, infective disease and in tumour therapy. The new developments in this field are the specific binding properties of a drug-carrying liposome to a target cell such as a tumor cell and specific molecules in the body (antibodies, proteins, peptides etc.); stealth liposomes which are especially being used as carriers for hydrophilic (water soluble) anticancer drugs like doxorubicin, mitoxantrone; and bisphosphonate-liposome mediated depletion of macrophages. This review would be a help to the researchers working in the area of liposomal drug delivery.

European Journal of Pharmaceutical Sciences, 2010

Blood-brain barrier (BBB) together with enzymes restricts the entry of substances for maintaining... more Blood-brain barrier (BBB) together with enzymes restricts the entry of substances for maintaining the internal milieu of the brain. Because of the presence of multiple endogenous transporters, BBB allows a selective entry of nutrients and minerals across it and limits the entry of foreign substances like drugs as well as neuropharmaceutical agents. This makes the CNS treatment ineffective. The conventional drug delivery systems which release drug into general circulation fail to deliver drugs effectively to brain and is therefore not very useful in treating certain diseases that affect CNS including Alzheimer's disease, dementia, Parkinson's disease, mood disorder, AIDS, viral and bacterial meningitis. Therefore there is a need to develop and design approaches which specifically target to brain in a better and effective way. The present review enlightens about several novel approaches including nanotechnology based approach like nanoparticles, liposomes, antibody mediated delivery approach and application of genomics in brain drug targeting that would give an insight to the researchers, academia and industrialists.

Current Pharmaceutical Design, 2009

Dendrimers represent a class of novel polymers having unique molecular architectures characterize... more Dendrimers represent a class of novel polymers having unique molecular architectures characterized by their well-defined structure, with a high degree of molecular uniformity, low polydispersity and properties that make them attractive materials for the development of nanomedicines. The dendrimer drug delivery can be achieved by coupling a drug through one of two approaches. Hydrophobic drugs can be complexed within the hydrophobic dendrimer interior to make them water-soluble or drugs can be covalently coupled onto the surface of the dendrimer. In addition, dendrimers have been shown to be capable of bypassing efflux transporters. A new generation of dendrimer-based delivery systems will enable the efficient transport of drugs across cellular barriers. This review deals principally with the synthesis, characterization and recent applications of dendrimers. In future it will only ever be possible to designate a dendrimer as safe means of drug delivery related to a specific application. However, so far limited clinical experience using dendrimers makes it impossible to designate any particular system which is safe and non toxic. Although there is widespread concern as to the safety of nanosized particles, preclinical and clinical experience gained during the development of polymeric excipients, biomedical polymers and polymer therapeutics showed that judicious development of dendrimer chemistry for each specific application will ensure development of safe and important materials for biomedical and pharmaceutical use.

Journal of Microencapsulation, 2009

Oral controlled release microspheres of rifampicin (RIF) were prepared in order to circumvent the... more Oral controlled release microspheres of rifampicin (RIF) were prepared in order to circumvent the required regular high dose of the conventional dosage forms for the treatment of tuberculosis. Rifampicin containing microspheres were designed by using a biodegradable and biocompatible polymer, gelatin B, using a thermal gelation method. The microspheres were cross-linked with natural cross-linker, sucrose, to avoid the toxicities due to the synthetic di- and poly-aldehydes. This formulation was found to be controlled release for drug in the gastro-intestinal tract. Drug encapsulation efficiency was found to be in the range of 52-83%. These microspheres were characterized for; particle size analysis by optical microscopy and scanning electron microscopy; in vitro release study by USP paddle apparatus and drug polymer interaction study using DSC and FT-IR. The results suggested that microspheres prepared by the above method were smaller in size, i.e. less than 60 microm and sucrose could be used as an interesting means to cross-link gelatin B microspheres, allowing the use of this formulation for controlled release of rifampicin. Microspheres could be observed in the intestinal lumen at 4 h and were detectable in the intestine 24 h post-oral administration, although the percentage of radioactivity had significantly decreased (t(1/2) of (99m)Tc = 4-5 h). Dissolution and scintigraphy studies have shown promising results, proving the utility of the formulation for the whole intestine.

Expert Review of Ophthalmology, 2007

... points. The performances of a mucoadhesive polysaccharide from tama-rind seed (xyloglucan or ... more ... points. The performances of a mucoadhesive polysaccharide from tama-rind seed (xyloglucan or tamarind seed polysaccharide [TSP]) as an adjuvant for ophthalmic vehicles containing timolol were evaluated. The polymer ...

Recent Patents on Anti-infective Drug Discovery, 2008

Tuberculosis (TB) is a highly infectious disease caused by several species of mycobacteria. Multi... more Tuberculosis (TB) is a highly infectious disease caused by several species of mycobacteria. Multi drug resistant strains of mycobacteria leading to the increase of patient world wide. There is an urgent need for new effective antimicrobial agent to replace those currently in use because of highly toxic. Screening methods available for discovering new chemical entities active against the resistant strains are detailed. The plant origin antimicrobial agents are the valuable anti tubercular drugs. The present review of patent stated several findings from an extensive literature search of semi synthetic, synthetic and natural plants that have been assessed for the antimicrobial activity over 20 years. An attempt has been made to summarize the information in order to highlight those chemical entities and plant species which are of worthy for further investigation as leads to the drug developments. Over 150 chemical entities of semi synthetic and synthetic and over 350 plant species from wide range of families containing various chemical classes of compounds have been cited here which are worthy for the researchers and the industrialist concerned to tuberculosis. The present review includes some patents relevant to the treatment of tuberculosis.

Current Diabetes Reviews, 2009

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by hyperglycemia caused by d... more Diabetes mellitus (DM) is a chronic metabolic disorder characterized by hyperglycemia caused by defective insulin secretion, resistance to insulin action, or a combination of both. DM has reached epidemic proportions in the US and more recently worldwide. The morbidity and mortality associated with diabetes is anticipated to account for a substantial proportion of health care expenditures. Although there are several drug treatments currently available, the need for new herbal agents for treatment of diabetes are required. The treatment goals for patients with diabetes have evolved significantly over the last 80 years, from preventing imminent mortality, to alleviating symptoms, to the now recognized objective of normalization or near normalization of glucose levels with the intent of forestalling diabetic complications. The present review stated several findings from an extensive literature search of natural plants that have been assessed for the anti diabetic activity over past 80 years. An attempt has been made to summarize the information in order to highlight those chemical entities and plant species which are of worthy for further investigation as leads to the drug developments. Over 100 plant species from wide range of families containing various chemical classes of compounds have been cited here which are worthy for the researchers and the industrialist concerned to diabetes.

Journal of Drug Targeting, 2008

is the first line anti-tubercular drug that is widely used in the treatment of tuberculosis. 99m ... more is the first line anti-tubercular drug that is widely used in the treatment of tuberculosis. 99m Tc-alginate-INH microsphere scintigraphy has been demonstrated to be a useful noninvasive imaging technique for microsphere deposits located in different organs of the rabbits. The aim of this study was to develop an improved formulation, to validate the formulation for long-time retention, as well as to assess radiotracer stability by novel quality control methods. Our study reports the labeling and evaluation of alginate blends-INH microspheres. The incorporation efficiency of optimized formulation was 89% w/w. The in vitro release study was carried out in simulated intestinal fluid at pH 7.4, and it was found that the formulation delivered the drug for 36 h. The labeling efficiency of 99m Tc-alginate blends-INH microspheres was seen at various pH (i.e. pH ranging from 5 to 7.5) and different concentration of stannous chloride dehydrate (i.e. 25 -200 mg) and it was concluded that 96% labeling efficiency was achieved in case of pH 7.5 and 60 mg stannous chloride. The stability study was carried out in saline and serum and it was found that the complex was highly stable in vitro and in vivo. The blood clearance in rabbits showed bi-exponential pattern depicting that 50% of activity washed out at 2 h with t 1/2(Fast) was 2.1 h and t 1/2(Slow) was 12.5 h. Bio-distribution was normal and the experimental mice showed major accumulation of the radiolabeled formulation in liver, intestine, lungs and kidneys, indicating hepatobiliary and renal route of excretion. The distribution of the drugs to the lung was showing its efficiency in the treatment of tuberculosis.

Current Drug Delivery, 2007

The discovery of liposome or lipid vesicle emerged from self forming enclosed lipid bi-layer upon... more The discovery of liposome or lipid vesicle emerged from self forming enclosed lipid bi-layer upon hydration; liposome drug delivery systems have played a significant role in formulation of potent drug to improve therapeutics. Recently the liposome formulations are targeted to reduce toxicity and increase accumulation at the target site. There are several new methods of liposome preparation based on lipid drug interaction and liposome disposition mechanism including the inhibition of rapid clearance of liposome by controlling particle size, charge and surface hydration. Most clinical applications of liposomal drug delivery are targeting to tissue with or without expression of target recognition molecules on lipid membrane. The liposomes are characterized with respect to physical, chemical and biological parameters. The sizing of liposome is also critical parameter which helps characterize the liposome which is usually performed by sequential extrusion at relatively low pressure through polycarbonate membrane (PCM). This mode of drug delivery lends more safety and efficacy to administration of several classes of drugs like antiviral, antifungal, antimicrobial, vaccines, anti-tubercular drugs and gene therapeutics. Present applications of the liposomes are in the immunology, dermatology, vaccine adjuvant, eye disorders, brain targeting, infective disease and in tumour therapy. The new developments in this field are the specific binding properties of a drug-carrying liposome to a target cell such as a tumor cell and specific molecules in the body (antibodies, proteins, peptides etc.); stealth liposomes which are especially being used as carriers for hydrophilic (water soluble) anticancer drugs like doxorubicin, mitoxantrone; and bisphosphonate-liposome mediated depletion of macrophages. This review would be a help to the researchers working in the area of liposomal drug delivery.

European Journal of Pharmaceutical Sciences, 2010

Blood-brain barrier (BBB) together with enzymes restricts the entry of substances for maintaining... more Blood-brain barrier (BBB) together with enzymes restricts the entry of substances for maintaining the internal milieu of the brain. Because of the presence of multiple endogenous transporters, BBB allows a selective entry of nutrients and minerals across it and limits the entry of foreign substances like drugs as well as neuropharmaceutical agents. This makes the CNS treatment ineffective. The conventional drug delivery systems which release drug into general circulation fail to deliver drugs effectively to brain and is therefore not very useful in treating certain diseases that affect CNS including Alzheimer's disease, dementia, Parkinson's disease, mood disorder, AIDS, viral and bacterial meningitis. Therefore there is a need to develop and design approaches which specifically target to brain in a better and effective way. The present review enlightens about several novel approaches including nanotechnology based approach like nanoparticles, liposomes, antibody mediated delivery approach and application of genomics in brain drug targeting that would give an insight to the researchers, academia and industrialists.

Current Pharmaceutical Design, 2009

Dendrimers represent a class of novel polymers having unique molecular architectures characterize... more Dendrimers represent a class of novel polymers having unique molecular architectures characterized by their well-defined structure, with a high degree of molecular uniformity, low polydispersity and properties that make them attractive materials for the development of nanomedicines. The dendrimer drug delivery can be achieved by coupling a drug through one of two approaches. Hydrophobic drugs can be complexed within the hydrophobic dendrimer interior to make them water-soluble or drugs can be covalently coupled onto the surface of the dendrimer. In addition, dendrimers have been shown to be capable of bypassing efflux transporters. A new generation of dendrimer-based delivery systems will enable the efficient transport of drugs across cellular barriers. This review deals principally with the synthesis, characterization and recent applications of dendrimers. In future it will only ever be possible to designate a dendrimer as safe means of drug delivery related to a specific application. However, so far limited clinical experience using dendrimers makes it impossible to designate any particular system which is safe and non toxic. Although there is widespread concern as to the safety of nanosized particles, preclinical and clinical experience gained during the development of polymeric excipients, biomedical polymers and polymer therapeutics showed that judicious development of dendrimer chemistry for each specific application will ensure development of safe and important materials for biomedical and pharmaceutical use.

Journal of Microencapsulation, 2009

Oral controlled release microspheres of rifampicin (RIF) were prepared in order to circumvent the... more Oral controlled release microspheres of rifampicin (RIF) were prepared in order to circumvent the required regular high dose of the conventional dosage forms for the treatment of tuberculosis. Rifampicin containing microspheres were designed by using a biodegradable and biocompatible polymer, gelatin B, using a thermal gelation method. The microspheres were cross-linked with natural cross-linker, sucrose, to avoid the toxicities due to the synthetic di- and poly-aldehydes. This formulation was found to be controlled release for drug in the gastro-intestinal tract. Drug encapsulation efficiency was found to be in the range of 52-83%. These microspheres were characterized for; particle size analysis by optical microscopy and scanning electron microscopy; in vitro release study by USP paddle apparatus and drug polymer interaction study using DSC and FT-IR. The results suggested that microspheres prepared by the above method were smaller in size, i.e. less than 60 microm and sucrose could be used as an interesting means to cross-link gelatin B microspheres, allowing the use of this formulation for controlled release of rifampicin. Microspheres could be observed in the intestinal lumen at 4 h and were detectable in the intestine 24 h post-oral administration, although the percentage of radioactivity had significantly decreased (t(1/2) of (99m)Tc = 4-5 h). Dissolution and scintigraphy studies have shown promising results, proving the utility of the formulation for the whole intestine.

Expert Review of Ophthalmology, 2007

... points. The performances of a mucoadhesive polysaccharide from tama-rind seed (xyloglucan or ... more ... points. The performances of a mucoadhesive polysaccharide from tama-rind seed (xyloglucan or tamarind seed polysaccharide [TSP]) as an adjuvant for ophthalmic vehicles containing timolol were evaluated. The polymer ...

Recent Patents on Anti-infective Drug Discovery, 2008

Tuberculosis (TB) is a highly infectious disease caused by several species of mycobacteria. Multi... more Tuberculosis (TB) is a highly infectious disease caused by several species of mycobacteria. Multi drug resistant strains of mycobacteria leading to the increase of patient world wide. There is an urgent need for new effective antimicrobial agent to replace those currently in use because of highly toxic. Screening methods available for discovering new chemical entities active against the resistant strains are detailed. The plant origin antimicrobial agents are the valuable anti tubercular drugs. The present review of patent stated several findings from an extensive literature search of semi synthetic, synthetic and natural plants that have been assessed for the antimicrobial activity over 20 years. An attempt has been made to summarize the information in order to highlight those chemical entities and plant species which are of worthy for further investigation as leads to the drug developments. Over 150 chemical entities of semi synthetic and synthetic and over 350 plant species from wide range of families containing various chemical classes of compounds have been cited here which are worthy for the researchers and the industrialist concerned to tuberculosis. The present review includes some patents relevant to the treatment of tuberculosis.

Current Diabetes Reviews, 2009

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by hyperglycemia caused by d... more Diabetes mellitus (DM) is a chronic metabolic disorder characterized by hyperglycemia caused by defective insulin secretion, resistance to insulin action, or a combination of both. DM has reached epidemic proportions in the US and more recently worldwide. The morbidity and mortality associated with diabetes is anticipated to account for a substantial proportion of health care expenditures. Although there are several drug treatments currently available, the need for new herbal agents for treatment of diabetes are required. The treatment goals for patients with diabetes have evolved significantly over the last 80 years, from preventing imminent mortality, to alleviating symptoms, to the now recognized objective of normalization or near normalization of glucose levels with the intent of forestalling diabetic complications. The present review stated several findings from an extensive literature search of natural plants that have been assessed for the anti diabetic activity over past 80 years. An attempt has been made to summarize the information in order to highlight those chemical entities and plant species which are of worthy for further investigation as leads to the drug developments. Over 100 plant species from wide range of families containing various chemical classes of compounds have been cited here which are worthy for the researchers and the industrialist concerned to diabetes.

Journal of Drug Targeting, 2008

is the first line anti-tubercular drug that is widely used in the treatment of tuberculosis. 99m ... more is the first line anti-tubercular drug that is widely used in the treatment of tuberculosis. 99m Tc-alginate-INH microsphere scintigraphy has been demonstrated to be a useful noninvasive imaging technique for microsphere deposits located in different organs of the rabbits. The aim of this study was to develop an improved formulation, to validate the formulation for long-time retention, as well as to assess radiotracer stability by novel quality control methods. Our study reports the labeling and evaluation of alginate blends-INH microspheres. The incorporation efficiency of optimized formulation was 89% w/w. The in vitro release study was carried out in simulated intestinal fluid at pH 7.4, and it was found that the formulation delivered the drug for 36 h. The labeling efficiency of 99m Tc-alginate blends-INH microspheres was seen at various pH (i.e. pH ranging from 5 to 7.5) and different concentration of stannous chloride dehydrate (i.e. 25 -200 mg) and it was concluded that 96% labeling efficiency was achieved in case of pH 7.5 and 60 mg stannous chloride. The stability study was carried out in saline and serum and it was found that the complex was highly stable in vitro and in vivo. The blood clearance in rabbits showed bi-exponential pattern depicting that 50% of activity washed out at 2 h with t 1/2(Fast) was 2.1 h and t 1/2(Slow) was 12.5 h. Bio-distribution was normal and the experimental mice showed major accumulation of the radiolabeled formulation in liver, intestine, lungs and kidneys, indicating hepatobiliary and renal route of excretion. The distribution of the drugs to the lung was showing its efficiency in the treatment of tuberculosis.