aquasomes

aquasomes

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  Prepared by :- Miss.Sanap Deepali S. M. Pharm 1st Year (Sem II). Roll No.13 Guided By :- Prof. A. W. Ambekar M. Pharm (Pharmaceutics) Dr. Vithalrao Vikhe Patil Foundation’s College of Pharmacy Ahmednagar (2018-2019) 1
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  CONTENTS  Introduction  Bodiesof water  Properties  Preparation  Evaluation  Advantages  Applications  References 2
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  INTRODUCTION  Aquasomes canbe defined as “nanoparticulate carrier system with three layered self assembled structures comprising of central solid nanocrystalline core coated with polyhydroxy oligomers onto which biochemically active molecules are adsorbed”.  First discovered by Nir Kossovsky in 1995. 3
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  BODIES OF WATER Water like properties.  Protect and preserve fragile biological molecules.  Maintain conformational integrity as well as high degree of surface exposure in targeting of bio-active molecules. 4
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  PROPERTIES  Preserves theconformational integrity of bioactive substances.  Deliver their contents through a combination of specific targeting, molecular shielding and slow sustained release.  Protects the drug from harsh pH conditions & enzymatic degradation.  Exhibit the physical properties of colloids.  Mechanism controlled by their surface chemistry.  Degradation can be achieved by monocytes and osteoclasts. 5
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  PREPARATION  Simple andstraight forward approach with minimum solvent usage.  No homogenization steps.  3 steps of preparation by using the principle of assembly :- 1. Preparation of the core - 2. Carbohydrate coating of core 3. Immobilization of drug molecule 6 i. Co precipitation ii. Self-Precipitation iii. Sonication iv. PAMAM
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  PREPARATION OF THECORE  Co-precipitation : 7 Diammonium hydrogen phosphate (0.19 N) solution drop wise added to calcium nitrate solution (0.32 M). pH maintained at 8–10 by addition of concentrated aqueous ammonia solution with continuous stirring at 75 °C in a three necked flask containing a reflux condenser, a thermometer fitted with a CO2 trap and a charge funnel. Stirr magnetically for 4-6 days at 75 °C & pH 8-10. Then , filter the precipitate, washed & dried overnight at 100 °C followed by sintering to 800–900 °C.
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   Self-Precipitation : 8 Adjustsimulated body fluid containing sodium chloride (134.8 mM), potassium chloride (5.0 mM), sodium hydrogen carbonate (4.2 mM), calcium chloride (2.5 mM), disodium hydrogen phosphate (1.0 mM), magnesium chloride (1.5 mM), and disodium sulfate (0.5 mM) to pH 7.26 every day with hydrochloric acid. Transfer the solution to a series of 100 ml polystyrene bottles, seal it tightly & kept at 37±1 °C for one week. Filter the precipitate, thoroughly washed with double distilled water & dried at 100 °C.
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   Sonication : PAMAM : • Carboxylic acid terminated half generation poly (amidoamine) (PAMAM) used. • Forms amorphous hydroxyapatite cores with a mixture of calcium phosphate. 9 Slowly add solution of disodium hydrogen phosphate to solution of calcium chloride under sonication at 4 °C for 2 h. Separate the precipitate by centrifugation & decant the supernatant. Wash the precipitate, re-suspend in distilled water & filter through membrane filter.
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  CARBOHYDRATE COATING OFCORE  Coating materials - Cellobiose, citrate, pyridoxal-5- phosphate, sucrose and trehalose.  Adsorption method –  Lactose coated by adsorption method by direct incubation and by nonsolvent addition. 10 Add of polyhydroxy oligomer to a dispersion of meticulously cleaned ceramics in ultra pure water. Sonicate & lyophilize it. Remove excess & readily desorbing carbohydrate either by stir cell ultrafiltration or by dialysis method.
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  IMMOBILIZATION OF DRUGMOLECULE  The drug can be loaded by partial adsorption. 11 Prepare the solution of drug with known concentration in suitable buffer. Disperse the coated particles in it. Keep the dispersion overnight at low temperature or lyophilize it.
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  12 Calcium phosphate (Brushite )OR Hydroxyapatite OR Ceramic diamond Drug AdsorptionCoating Polyhydroxyl compound Ceramic core Coated core Drug loaded aquasome Fig : Preparation of aquasomes Core Coat Drug
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  EVALUATION 13 Evaluation of ceramic core Evaluationof sugar coating Evaluation of drug loaded aquasomes Structure analysis Phase analysis of core Particle morphology Colorimetric analysis Concanavalin-A induced aggregation Zeta potential Size & shape Glass transition temperature In vitro drug release studies Drug loading efficiency Antigen loading efficiency Hb loading capacity
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  EVALUATION OF CERAMICCORE  Structure analysis - Interpretated by Fourier transformed infrared spectroscopy using hydroxyapatite powder in the wave no. range of 4000- 400 cm-1.  Phase analysis of core - Cores exposed to Cu K-α radiation in a wide angle X-ray diffractometer.  Particle morphology - Determined by using transmission electron microscopy one drop of aqueous dispersion is placed over a 400-mesh carbon-coated copper grid followed by negative staining with phosphotungstic acid and placed at the accelerating voltage. 14
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  EVALUATION OF SUGARCOATING  Colorimetric analysis – (Anthrone method) 15 Preparation of aliquots of sample for calibration curve. Transferred it to boiling tubes & diluted to an appropriate concentration. Addition of anthrone reagent, heated in a boiling water bath & cooled rapidly. Absorbance recorded after the formation of greenish solution using UV-visible spectrophotometer (glucose used as standard).
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   Concanavalin-A-Induced aggregation 16 Takesugar-coated HA core suspensions in quartz cuvettes. Addition of Concanavalin-A solution to it. Determination of absorbance at 450 nm as a function of time of 5 min interval using UV-visible spectrophotometer. Obtained data subtracted from blank experiment conducted in the absence of concanavalin-A.
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  EVALUATION OF DRUGLOADED AQUASOMES  Size & shape – • Morphological examination - Transmission electron microscope. • Mean particle size & size distribution - A photon correlation spectroscopy using a Autosizer II C apparatus and SEM. • Chemical composition & crystalline structure - X-ray powder diffractometry.  Glass transition temperature – • carbohydrates and proteins studied by using DSC analyzer.  In-process stability studies – • Stability and integrity of protein during the formulation of the aquasomes determined by using sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE). 17
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   In vitrodrug release studies- • To study the release pattern of drug 18 Incubate a known quantity of drug loaded aquasomes in a buffer of suitable pH at 37°C with continuous stirring. Samples are withdrawn periodically & centrifuged at high speed for certain lengths of time. Equal volumes of medium replaced after each withdrawal. Supernatants are then analyzed for the amount of drug released.
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   Drug loadingefficiency - • Ensure the amount of drug which is bound on the surface of aquasomes.  Hb loading capacity – ( Drabkin’s method ) • Estimated by the difference between the control sample (HbA solution) and the free hemoglobin contained in all fractions without nanoparticles.  Antigen loading efficiency – • Unit : g of antigen/mg of sample. 19 Weigh antigen-loaded aquasome formulations , suspend it in Triton X-100 & incubate in a wrist shaker for 1 h. Centrifuge the sample & determine absorbance using micro- BCA methods with set a blank of unloaded aquasomes formulation.
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  ADVANTAGES  Increases therapeuticefficacy of pharmaceutically active agents.  Avoid multiple-injection schedule.  Offer favorable environment for proteins.  Used for various imaging tests.  Novel carrier for enzymes such as DNAses and pigment/dyes.  Act as a vaccine delivery system. 20
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  APPLICATION  Oxygen carrier For immunotherapy  For oral route  For immunopotentiation  Anti thrombic activity  Antigen delivery  Delivery of poorly soluble drugs  Enzyme delivery  Insulin delivery  Vaccine delivery 21
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  REFERENCES  Narang N.Aquasomes: Self-assembled systems for the delivery of bioactive molecules. Asian Journal of Pharmaceutics. April-June 2012: 95-100.  Banerjee S, Sen KK. Aquasomes: A novel nanoparticulate drug carrier. Journal of Drug Delivery Science and Technology. 2018: 446–452. 22
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