Background: Amidst levodopa being considered as the “Gold standard” in the treatment of Parkinson’s disease (PD), it still has critical therapeutic issues with its dose regimen and dosage forms leading to severe adverse drug effects, decreased drug efficacy during chronic use, and requires an enforced “drug holiday” in PD patients. Hence, in this study, we designed a novel levodopa and carbidopa water-in-oil-in-water (w/o/w) formulation for bioavailability improvement in the central nervous system (CNS). Methods: The new one-in-one embedment of the w/o/w levodopa and carbidopa emulsion formulation was obtained by a double emulsion technique. The plasma and brain levels following intravenous administration of the emulsions in rats were determined. Results: The incorporation of stearylamine (a cationic surfactant) considerably increased the surface charge density of the emulsion droplets. This formulation exhibited a narrow particle size distribution enabling parenteral administration. The formulation also provided a high drug loading capacity. In in vivo study, this novel formulation significantly increased the bioavailability of levodopa in the CNS (P < 0.001). The strong resistance to desorption (due to higher charge density) and the presence of positive charge on the particles upon dilution may be the main reason for enhanced brain levels of levodopa. Conclusion: Our current formulation F5 may decrease the dose of levodopa, leading to decreased adverse effects and dosing problems, thus appreciably benefit PD patients in the future.

Purpose: The objective of this study was to evaluate the ability of nano-droplets of Self Nano Emulsifying Drug Delivery System to diffuse into the brain tissue. Methods: The preconcentrate was prepared by dissolving oils, surfactants and cosolvents in 1:1 mixture of methanol and chloroform and flash evaporated at 50°C and was stored at room temperature until their use in subsequent studies. CSEDD with surfactant polysorbate-80 were radiolabel led with radioactive C18 triglyceride. The nanodroplets formed by CSEDD in 5% dextrose were subjected to evaluation in blood and brain. Results: The intravenous pharmacokinetics of carbamazepine in rats of CSEDD formulation generated high initial serum levels (5.25 mcg/ml) at 0.25 h when compared to C-Sol (3.91 mcg/ml) at 0.5 h. It was found that oil to surfactant ratio had an impact on the physical characteristics of the nano-emulsion formed. The brain levels of CBZ from optimized CSEDD were significantly high at all-time points when compared to plain solution. The initial levels of CBZ from CSEDD was 8.023 mcg/ml thereafter the levels were consistently high till 8 h and the initial levels of CBZ from plain solution was 3.62 mcg/ml followed by a gradual decline till 4 h evidently showing that the clearance of CBZ from CSEDD was reduced. The brain targeting index of CSEDD and solution were 3 and 2 respectively. The brain enhancement factor value was found to be 22.29 at 15 min revealing a very rapid penetration of CBZ into brain. Conclusions: This study proposes intravenous CSEDD as a new brain delivery system and highlights two requirements to design adequate delivery systems for long circulating properties of the carrier and appropriate surface characteristics to allow interactions with BBB endothelial cells.

The present research work was aimed at the enhancement of solubility of Candesartan by Self Emulsifying Drug Delivery Systems (SEDDS). Candesartan is a BCS class II drug having low aqueous solubility and high permeability; hence its bioavailability is solubility rate limited. The saturated solubility of Candesartan in various oils and surfactants was determined. The excipients were screened and selected showing maximum solubility and compatibility for Candesartan. SEDDS formulations of Candesartan were developed using different Oils, Surfactants and Co-Surfactant combinations. Pseudoternary phase diagrams were constructed using Triplot V 4.1.2 software and applying Pseudoternary phase diagrams, microemulsification area was evaluated. Formulations were prepared based on phase diagrams using various proportions of oil, surfactants and co-surfactants. The formulations were screened visually for stability and phase separation. Seven formulations were selected for further evaluations like effect of dilution, freeze-thawing, emulsion droplet size and zeta potential. Among the seven formulations three were optimized and filled in hard gelatin capsules. The in-vitro dissolution studies of the SEDDS formulation were performed and the dissolution rate of SEDDS was compared with plain Candesartan (API). The results indicated that the solubility and dissolution rate of Candesartan was significantly higher than that of plain drug (API). The results of the present studies demonstrate that SEDDS can be used as a potential means for improving solubility, dissolution and bioavailability of Candesartan.

The current study aimed to evaluate long-chain alkyl esters of p-amino benzoic acid (PABA) as possible new class of permeation enhancers. In this study we have synthesized long-chain alkyl esters of PABA (decyl, dodecyl, and tetradecyl) by a novel and facile method in our laboratory. The PABA derivatives were incorporated into solid lipid nanoparticles and characterized for size, zeta potential and entrapment efficiency. In vitro permeation study was carried out using rat abdominal skin and permeation enhancement was assessed from the permeation parameters (flux, permeability coefficient, and enhancement ratio). Among the formulations tested, Dodecyl PABA containing solid lipid nanoparticles (SLN) has shown a significant enhancement in the permeation of diclofenac compared to control and other PABA derivatives containing solid lipid nanoparticles. The increase in permeation parameters clearly indicates the potential of PABA derivatives as a novel amphiphile that can be explored as a new class of permeation enhancers in topical drug delivery.

The aim of this study is to develop ascorbyl palmitate (ASP) loaded doxorubicin (DOX) pegylated liposomes and to evaluate their targeting potential to tumor. We have prepared conventional (DL), pegylated DOX liposomes with (SDL) and without ascorbyl palmitate (SDL-A). The vesicle size in all the formulations was within the range 105--120 nm and in vitro release studies in serum confirmed the stability of the liposomes. Biodistribution studies carried out in Ehrlich ascites tumor bearing mice indicate higher area under the curve for SDL and SDL-A liposomes compared to DL and plain drug solution. Drug targeting index assessed from tumor-to-serum concentration ratio and therapeutic availability of DOX in tumor tissue was also significantly higher for pegylated liposomes. In conclusion, biodistribution study reveals that the presence of ascorbyl palmitate alters the distribution pattern of liposomes and paves way for better drug targeting.</.

The present work wa s aimed at the enhancement of solubility of Fenofibrate a BCS class II drug by Self Emulsifying Drug Delivery systems (SEDDS) . The solubility of Fenofibrate in various excipients was determined. The excipients were screened for maximum solubility and compa tibility. SEDDS formulations of Fenofibrate were developed using different Oils, Surfactants and Co - Surfactant combinations. Pseudoternary phase diagrams were drawn using Triplot software and by applying Pseudoternary phase diagrams , microemulsification ar ea was evaluated. Formulations were screened based on visual observances and phase diagrams. Seven formulations were selected for further evaluations like stability, effect of dil ution, freeze thawing, emulsion droplet size and zeta potential. Among the se ven formulations three were optimized and In - Vitro dissolution was performed. The dissolution rate of SEDDS was compar ed with plain Fenofibrate (API) . The study confirmed that the solubility and dissolution rate of Fenofibrate w ere remarkably increased whe n compared to that of plain drug. Hence SEDDS formulations can be a potential alternative to traditional oral drug delivery systems of Fenofibrate to improve its bioavailability

Callus cultures of Withania somnifera from leaves were established on MS (Murashige and Skoog) media supplemented with Dicamba (2 mg/l), Kinetin (0.1 mg/l) and Sucrose (3% w/v). Suspension cultures were established and the growth and production kinetics were studied. For growth kinetics MS media supplemented with Dicamba (2 mg/l), Kinetin (0.1 mg/l) and Sucrose (3% w/v) without agar was used which was found suitable for the initiation and maintenance of the suspension cultures cultures from the calli. Half B5 medium supplemented with 2,4- Dichlorophenylacetic acid(2,4-D) (1 mg/l), Kinetin (0.1 mg/l) and Sucrose (5% w/v) was employed. Effect of various precursors and elicitors on suspension cultures was studied. The addition of precursor’s sodium acetate (50 mg/l) (~10 folds), Mevalanolactone (50 mg/l) (~14 folds), Squalene (50 mg/l) in colloidal form (~23 folds) and Cholesterol (25 mg/l) in colloidal form (~30.5 folds) have shown significant increase in bioproduction of withaferin A. Among the various biotic and abiotic elicitors used Verticillium dahliae (5% w/v cells extract) (~10 folds) and copper sulphate (100μm/l) (~2.5 folds) have shown moderate increase in the bioproduction of withaferin A. The effective precursors and elicitors were studied for optimization of day of addition and found that maximum bioproduction of withaferin A was seen in the cultures when precursors and elicitors were added to 3 day old suspension cultures.

A high-performance liquid chromatography/electrospray ionization tandem mass spectrometry method was developed and validated for the quantification of zidovudine in rat plasma. Following solid-phase extraction, the analytes were separated using an isocratic mobile phase on a reverse phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M+H]+ ions, m/z 268/127 for zidovudine and m/z 230/112 for the internal standard. The method exhibited a linear dynamic range of 5-500 ng/mL for zidovudine in rat plasma. The lower limit of quantification was 5 ng/mL with a relative standard deviation of less than 8%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 1.5 min for each sample made it possible to analyze more than 400 plasma samples per day. The validated method was applied for pharmacokinetic studies of the novel drug delivery systems of zidovudine in rats.

Carbamazepine (CBZ) is used in the treatment of generalized tonic clonic and partial seizures. In seizure disorder the focal point of treatment is brain. At present no commercial parenteral formulation of CBZ is available. We developed o/w nanoemulsions of CBZ stabilized by 1-O-alkylglycerol/lecithin for intravenous administration and evaluated the brain targeting potential of these formulations. The nanoemulsions were characterized for globule size, zeta potential (ZP), CBZ content and in vivo tissue distribution in mice. The in vivo data revealed a significant uptake of CBZ in all tissues. Among the nanoemulsions, 1-O-decylglycerol stabilized system showed significantly higher tissue levels and availability of CBZ. Particularly for this system 2.37 times higher brain availability and a brain/serum concentration ratio of 3.0 at 30 min is an important finding. This indicates the brain targeting potential. A systematic formulation development of CBZ nanoemulsions employing 1-O-alkylglycerols might pave way to achieve selective brain delivery of this important antiepileptic drug.

Size of oil globule and emulsifier film covering it are the key factors modifying oral absorption of drugs dissolved/dispersed in oil globules of o/w emulsions. Since oral bioavailability of flutamide (FTM) is poor, nanoemulsions incorporating FTM in oil phase and globules stabilized by a novel lipophilic emulsifier, 1‐O‐alkylglycerol were developed and characterized. All nanoemulsions had a size around 200 nm. They exhibited considerable release retardation in vitro. Flutamide nanoemulsions were evaluated for oral bioavailability in rabbits and in situ intestinal absorption in rats. Serum level data of flutamide obtained in the in situ experiments indicate higher FTM absorption from nanoemulsions than the aqueous FTM suspension. Among the nanoemulsions, 1‐O‐alkylglycerol stabilized systems showed higher absorption. The results of bioavailability studies in rabbits indicate increased absorption and decreased elimination of FTM from nanoemulsions, thus improving the bioavailability. Increased rate of absorption of flutamide in the in situ experiments can be attributed to the permeation enhancement effect of 1‐O‐alkylglycerols. However, size of the oil droplet seems to be the major factor in improving oral bioavailability in rabbits.

A rapid, reliable HPLC method with UV detection (240 nm) was developed and validated for quantitation of saquinavir in mice brain and testis. Saquinavir and the internal standard were isolated from homogenized tissue matrices using liquid-liquid extraction procedure and were then analyzed using an isocratic mobile phase by reversed-phase liquid chromatography. The lower limit of quantification was 50 ng/g for both brain and testis. A linear dynamic range of 50-5000 ng/g for both brain and testis was established. This HPLC method was validated with between-batch precision of 0.5-4.4 and 1.5-5.5% for brain and testis, respectively. The between-batch accuracy was 94.7-105.9% and 97.5-105.0% for brain and testis, respectively. The present method was applied for tissue distribution studies of the novel drug delivery systems of saquinavir in mice.

In vitro permeation of nabumetone across rat skin from nanoemulsions of soybean oil in 2.5% aqueous glycerol stabilized with a blend of lecithin and 1-O-alkylglycerol (C-10 , C-12 , C-14 , or C-16 chain length) was studied. The mean droplet size of the emulsions was in the range of 214 to 280 nm. 1-O-Alkylglycerol stabilized emulsions showed significant enhancement in permeation of nabumetone. This enhancement is attributed to the interaction of 1-O-alkylglycerol with the skin lipids, fluidizing the lipid matrix and bringing about disordering effect. The extent of interaction appears to depend on chain length of 1-O-alkylglycerol. 1-O-Decylglycerol stabilized emulsion showed highest flux in the first four hours and did not exhibit any lag time. The other emulsions showed increase in lag time with increase in the chain length of 1-O-alkylglycerol. Control nabumetone solution exhibited highest overall flux, but it showed lower flux than nanoemulsions stabilized by 1-O-decylglycerol for the initial four hours and a significantly higher flux thereafter. This appears to be due to slow extraction of skin lipid by the solvent action of control solution and consequent permeabilization of the skin.

Vesicles with biological activity or with a targeting function in addition to carrier properties will have an added advantage. Vesicles prepared with amphiphiles having antioxidant property may have potential applications towards disorders implicated with reactive oxygen species. Ascorbyl palmitate (ASP) was explored as bilayer vesicle forming material. It formed vesicles (Aspasomes) in combination with cholesterol and a negatively charged lipid (dicetyl phosphate). Aspasomes were prepared by film hydration method followed by sonication in which aqueous azidothymidine (AZT) solution was encapsulated in aqueous regions of bilayer. Aspasomes were obtained with all compositions containing 18-72 mol% cholesterol. Differential scanning calorimetric data of aspasome dispersion and anhydrous mixtures of ascorbyl palmitate, cholesterol and dicetyl phosphate confirm the formation of bilayered vesicles with ascorbyl palmitate.Cholesterol content in aspasome did not exhibit any relation with vesicle size, zeta potential or percent entrapment. A substantial change in release rate of azidothymidine from aspasome was noticed on varying the proportion of cholesterol. Release rate and cholesterol content in Aspasomes did not exhibit any relation. A preparation with 45 mol% of cholesterol showed maximum retardation in release rate, than other compositions. The change in capture volume with time (latency) was studied for 8 h and with such a short duration study it was difficult to predict long term stability of these vesicles. But release experiments do indicate stability upto 18 h.Percent reducing activity of aspasome was estimated by measuring the absorbance of a,a-diphenyl-p-picrylhydrazyl (DPPH) at 517 nm after addition of test antioxidant samples. These studies revealed that the antioxidant potency of ascorbyl moiety is retained even after converting ascorbyl palmitate into vesicles (Aspasomes). The antioxidant potency of Aspasomes was assessed by measuring the protection offered by this preparation against quinolinic acid induced lipoperoxidation of whole human blood in vitro, where in the lipoperoxidation was monitored by measuring thiobarbituric acid reactive substances (TBARS) levels. Aspasome rendered much better antioxidant activity than ascorbic acid.Transdermal permeation of aspasomal AZT, ASP-AZT aqueous dispersion and AZT-solution across excised rat skin was investigated in vitro using Franz diffusion cell. Permeation of aspasomal AZT was much higher than the other two preparations. However, ASP-AZT aqueous dispersion has also enhanced permeation of AZT significantly over the AZT-solution, indicating skin permeation enhancing property of ascorbyl palmitate. (C) 2003 Elsevier B.V. All rights reserved.

Monomers of some amphiphiles organize into bilayers to form liposomes and niosomes. Such bilayers are unstable or leaky and hence cholesterol is a common ingredient included to stabilize them. Cholesterol stabilizes bilayers, prevents leakiness, and retards permeation of solutes enclosed in the aqueous core of these vesicles. Other than cholesterol a material with good bilayer-stabilizing properties is yet to be identified. We have substituted cholesterol with fatty alcohols in niosomes containing polyglyceryl-3-di-isostearate (PGDS) and polysorbate-80 (PS-80) to explore their membrane-stabilizing property via permeation studies. Niosomes of polyglyceryl-3-di-isostearate, fatty alcohol/cholesterol, and polysorbate were prepared by ether injection method. Aqueous solution of ketorolac tromethamine (KT) was entrapped in them. The effects of alkyl chain length of fatty alcohols (C(12), C(14), C(16), C(18), and C(16+18)), of acyl chain length of polyoxyethylene sorbitan monoester surfactants, and of the molar ratio of lipid mixture on the release rate of ketorolac from niosomes were assessed by employing modified dissolution-dialysis method. Niosomes with cholesterol or fatty alcohols have exhibited a common release pattern. Niosomes containing fatty alcohol showed a considerably slower release rate of KT than those containing cholesterol. Based on the release rate, fatty alcohols can be ranked as stearyl<myristyl<cetyl<lauryl<cetostearyl. In niosomes containing PGDS, myristyl alcohol (MA), and polysorbate, the fatty acid chain length of polyoxyethylene sorbitan ester-type surfactants has influenced the release rate and encapsulation efficiency. Based on the release rate, polysorbates can be ranked as polysorbate-20 (C(12))<polysorbate-60 (C(18))<polysorbate-80 (C(9=9))<polysorbate-40 (C(16)). In niosome preparation containing polysorbate-20 and dioctyl sodium sulfosuccinate (anionic surfactant), the release rate was slower than niosomes containing polysorbate-20. When MA concentration is kept constant at 50 mole% and the ratio of PGDS and PS-80 was altered, significant changes in entrapment efficiency and the release rate were observed. However, this ratio did not exhibit any relation with encapsulation efficiency or release rate. The release rate and entrapment exhibited an inverse correlation (r(2)=0.8774 at p<0.02 for the data of molar ratios of PGDS:MA:PS80; r(2)=0.975 at p<0.001 for the data of acyl chain length variation of polysorbates). It can be concluded that stable niosomes of polyglyceryl-3-di-isostearate could be prepared with fatty alcohols and polysorbates instead of cholesterol and that the release of solutes from these niosomes can be optimized by altering membrane constituents and their concentrations.

1-O-alkylglycerols (ALKG) have exhibited several biological activities and a prominent effect on blood-brain barrier permeability. They have markedly improved brain uptake of cancerostatic agents. Since ALKG are amphiphilic, we explored their tendency to assemble into bilayer vesicles, which can be applied as carriers for drugs. Vesicles (Algosomes) were formed by film hydration method using ALKG (tetra-, penta-, hexa-, hepta-, octa- or nona-decylglycerols) in combination with cholesterol (CHOL) and dicetyl phosphate (DCP) (1-O-alkylglycerol:CHOL:DCP in 45:45:10 molar ratio). On microscopic examination, the algosomes were found to be conspicuously spherical and the dispersion was a mixture of multi-lamellar and small-unilamellar vesicles. Phase transition temperatures of 1-O-hexadecylglycerol (HXDG) and CHOL mixtures were tested by differential scanning calorimetry (DSC). The changes in phase transition temperatures indicate the vesicle forming tendency of ALKG in presence of CHOL. Alkyl chain length dependent variations in vesicle size, zeta-potential (ZP) and capture volume (CV) could not be observed. Vesicles of 1-O-tetradecylglycerol (TTDG) showed improvement in CV with increase in CHOL content from 15 to 55 mol%. However the vesicle size decreased. On challenging algosomes with hypertonic salt solution [potassium iodide (KI) in water], vesicle size decreased and thus algosomes were found to be osmotically sensitive. Algosome dispersions on addition of higher concentrations of KI (40–100 mM) brought about increases in vesicle size and at concentrations 60 mM and above showed aggregation. All vesicular dispersions were stable for only a few days.

Several insoluble drugs when prepared as solid dispersions showed improved solubility and dissolution. Techniques of melting and melt-solvent methods were used to prepare solid dispersions to enhance the solubility of poorly soluble sulphamethoxazole. Solid dispersions of various compositions were prepared using mannitol as carrier. An improvement in the solubility and dissolution rates of sulphamethoxazole from solid dispersions was observed. Solid dispersions of sulphamethoxazole mannitol in the proportion of 1:2 prepared by melting and melt solvent method were developed into tablet dosage forms by both wet granulation and direct compression methods. The solid dispersion tablets were evaluated and compared with some of the sulphamethoxazole-trimethoprime conventional tablets available commercially (only sulphamethoxazole was estimated). Solid dispersion tablets of melt solvent method prepared by direct compressable method have shown highest dissolution rate.

Clotrimazole (CLTZ) solid dispersions of various compositions were prepared by melting or melt-solvent methods using mannitol as carrier. Cream base of O/W type was prepared by emulsification method and the solid dispersion were incorporated in cream base by trituration. The in vitro antifungal activity of CLTZ solid dispersion creams were estimated using the test organism Candida albicans. The interaction of sulphamethoxazole (SMZ) with CLTZ in the form of solid dispersion creams were also estimated for their antifungal activity. improved antifungal activity was found with CLTZ solid dispersions. However, there was no significant improvement in the activity in presence of SMZ.

The callus cultures of A. indica leaves and flowers were established for the production of azadirachtin. The 12-week old flower callus produced 2.46% of azadirachtin.