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Core-shell nanoparticles are preferable due to their new and/or improved properties over monometallic nanoparticles. Shell metals are present as a film on the surface of a core metal, which leads to an increase in reactivity of the surface. The synthesis of core-shell nanoparticles using biomolecules is an important strategy to get more activity with less toxicity. The present work was intended to prepare bimetallic nanoparticle preparation by green synthetic method. Aqueous extract of Muntingia calabura flowers was used for the preparation of metal core-shell nanoparticles where flower extract acted as both reducing agent and stabilizing agent. Monometallic gold nanoparticles (AuNPs) and silver nanoparticles (AgNP) were prepared using metal precursors chloroauric acid (HAuCl4) and silver nitrate (AgNO3), respectively. For the preparation of bimetallic core-shell nanoparticles, a shell metal precursor (copper acetate) was added. The obtained nanoparticles were characterized by various instrumental methods including UV–Vis spectrophotometry, TEM and SEM techniques, and EDX spectral analysis. Preliminary antibacterial screening of Au@Cu NP and Ag@Cu NP was performed by disk diffusion assay. TEM and SEM images showed that Au@Cu NPs were spherical whereas Ag@Cu NPs had irregular shapes. The EDX analysis revealed that more Cu was deposited in AuCuNPs than in AgCuNPs. The antibacterial activity assay proved that spherical AuCuNPs were more potent than irregular shaped AgCuNPs.

Chitosan is a natural biopolymer, which is extensively used in the formulation of colon-targeted drug-delivery systems. Chitosan-based systems lead to the release of drugs at the colon region by the subsequent degradation of chitosan. This degradation of chitosan occurs through the lysis of glycosidic bonds by the colonic microflora. Native chitosan and different chitosan derivatives, such as carboxymethyl chitosan, trimethyl chitosan, thiolated chitosan, N-succinyl chitosan, PEGylated chitosan, folic acid-conjugated chitosan, hyaluronic acid-coupled chitosan, etc., have widely been used in colon-targeted systems for the effective delivery of therapeutics.

Alginates (ALGs) are the product of alginic acid, which is a marine-derived naturally occurring polysaccharide having excellent biodegradability and biocompatibility. Since long, ALGs have widely been studied and utilized in many medical and biomedical areas, including drug delivery. For the formulation of various dosage forms, ALGs are commonly used as pharmaceutical excipients in many drug delivery dosage forms. Numerous composite systems based on ALGs have already been explored and exploited to facilitate the releasing of drugs for the therapy of different illnesses. Several inorganic biomaterials, such as carbon nanotube (CNT), montmorillonite (MMT), calcium silicate (CS), β-tricalcium phosphate (β-TCP), and hydroxyapatite (HAp) have already been reinforced into the ALG matrices to enable the long-term and more precise release of different drugs. Additionally, these composites have been formulated to improve desired mechanical behavior. The present chapter provides an extensive overview on the reported researches on the inorganic materials–ALG composite systems for drug releasing.

Herein, a facile scale up and shape variable synthesis of gold nanoparticle (AuNP) and reaction mechanism by natural xanthone derivative (mangiferin) has been reported. Mangiferin (C19H18O11; 1,3,6,7-tetrahydroxyxanthone-C2-β- d -glucoside), a xanthone derivative is isolated from Mangifera indica L. leaves which efficiently reduces Au3+ ions to Au0 and stabilizes the formed AuNP. The structural, optical and plasmonic properties of synthesized AuNP have been investigated through different instrumental techniques like UV–Vis and FTIR spectroscopy, powder XRD, FESEM and TEM analysis. It is observed that variation of the concentration of Au3+ ions and mangiferin has a great effect on controlling size and shape of nanoparticles. The role of reaction temperature is also notable. An interesting observation is that with same concentration ratio of HAuCl4/mangiferin (0.025 mM/0.002%) at the room temperature kidney shaped AuNP is produced, whereas it is spherical at boiling temperature. Moreover, mangiferin allows high scale synthesis of AuNPs (0.025 mM to 10 mM) without changing the particles size and shape. The mechanistic investigation through UV–Vis, FTIR and GCMS analyses reveal the cleavage of glucose unit and oxidation of phenolic OH groups during AuNP formation. Non-toxicity of mangiferin conjugated AuNP on normal human breast cell line (MCF-10A) suggesting its future application as a drug delivery system and other related medicinal purposes.

The paper describes HPLC, UV spectrophotometric and non aqueous titrimetric method for the estimation of poorly water soluble protease inhibitor. Ritonavir in raw material and tablet dosage form. HPLC analysis was carried out in a C18 column using acetonitrile, methanol, and buffer in the ratio 60: 20: 20 (v/v/v) at 240 nm. For the spectrophotometric determination, methanolic solution of Ritonavir was reacted with 3-methyl benzothiazolin-2-one hydrazone (MBTH). The oxidative coupled green coloured chromogen was analysed at 633 nm. Non aqueous titration was carried out using perchloric acid as titrant and the end point was determined using crystal violet as indicator. The three methods were validated and statistically evaluated to correlate the difference between the methods for estimation of Ritonavir in pharmaceutical dosage form.

Two chromatographic methods are developed and validated to estimate Atazanavir Sulfate and Ritonavir in new fixed dosage form, that is, tablet dosage form named Synthivan. The first method is based on HPLC separation of the two drugs on the reversed phase HiQSil C18 column (5 µm, 250 × 4.6 mm) at ambient temperature using an isocratic solvent system consisting of acetonitrile and water in the ratio 52:48 (v/v). Quantification is achieved with a PDA detector at 254 nm at a flow rate of 1.5 mL/min. Linearity of concentrations is found at 60–600 µg/mL and 20–200 µg/mL for Atazanavir sulfate and ritonavir, respectively. The second method is based on HPTLC separation of the two drugs on pre-coated silica gel 60F254 aluminum plates using toluene:methanol:glacial acetic acid:ethyl acetate (7:0.5:1.5:2, v/v/v/v) as solvent system followed by densitometric measurements of their spots at 254 nm. The linearity of the concentration is found to be 30–300 and 10–100 ng/spot for Atazanavir Sulfate and Ritonavir, respect...