1. INTRODUCTION
Crystallization is an essential technique in pharmaceutical manufacturing since most of the active pharmaceutical ingredients (API) are available in a solid form1. It plays an important role in marketing, manufacturing, and including interaction with excipients in the crystalline state2.
The physical properties of the active pharmaceutical ingredients such as crystalline form, morphology and particle size distribution will strongly affect the solubility and bioavailability of a solid dosage form (Table 1) 3.
The process of crystallization, especially crystallization from solution, is used as a separation and purification technique and in the production of pharmaceutical solid forms3,4. Knowledge of the crystal structure allows the crystal engineer to know and manipulate the chemistry of the crystal in order to optimize exact characteristics performance 3.
Furthermore chemical and physical properties of a material are dictated by crystallization process. The crystal properties such as: particle size, shape, surface characteristics, purity and defect structure, as well as thermodynamic and mechanical properties3 will be affected even by minor changes in crystallization conditions5.
1.1 Crystal
A crystal is defined as a solid form that contains a very high degree of internal three-dimensional order of the components atoms, molecules and ions2. The crystal structure of atoms and molecules has a unique arrangement, which leads to the regular repeat of interatomic distances within the material4.
The shape of a crystal is a reflection of its inner, atomic-scale structure. The faces of a crystal are labelled with respect to the crystal axes. Each face has a set of three integers (h, k, l), which are known as Mill...
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...ed to provide sufficient data to determine the unit cell and crystal system30-35. Once the optimum data collection is automatically calculated by the control system, a complete set of images is recorded, which will provide the full data set required for the structure determination35.
4.2 X-ray Powder Diffraction
Powder diffraction is used for the identification of unknown materials. For a powder, the spots seen in single-crystal patterns are smeared into powder rings. In X-ray powder diffraction, there is no need to move the sample in the powder diffractometer, because for every Bragg crystal plane, some crystallites statistically will be orientated correctly34.
All necessary information that requires identifying a phase through comparison with a database of patterns from known materials is provided when a single radial scan is showed35.
Purpose: To identify the mystery powder based on its physical and chemical properties, comparing them to the five substances and which one matches. The chemical reactions with water, universal indicator, vinegar and Iodine solution are then analyzed and matched with each other to determine the mystery powder.
By comparing the texture of each, we can immediately eliminated baking powder, chemically known as NaHCO3, because it had a finer texture and lacked the crystalline structure evident in Figure 2B. The remaining suspects would then be table salt or NaCl in Figure 2D or Epsom salt in Figure 2E. In continuing to compare crystal structures, table salt had a blocky, cubic crystal structure; whereas Epsom salt contained more irregularly shaped particles, most of which appeared to be pentagons. Figure 2B showed that the crystal structure of the salt was in no way cubic or regularly-shaped, eliminating it from the list of possible constituents. That would leave behind Epsom salt as the identity of the salt from
Dai, X., Reading, M., & Craig, D.Q.M. (2008). Mapping Amorphous Material on a Partially Crystalline Surface: Nanothermal Analysis for Simultaneous Characterisation and Imaging of Lactose Compacts. Journal of Pharmaceutical Science, 98, 1499–1510.
When making an organic compound, it is important to separate the compound from other compounds to make it as pure as possible, this is called crystallization.
The general objective of this experiment was for the students to familiarise with the preparation of a simple organic compound and to purify the compound by recrystallization. This experiment allows the students to conduct synthesis of aspirin, reinforcing the skills of recrystallization and the technique of melting point determination.
In this case study, our concern goes for the chitosan nanoparticles; firstly nanoparticles are able to adsorb and/or encapsulate a drug, thus protecting it against chemical and enzymatic degradation. Furthermore the encapsulated drug may be prevented from crystallization, thus forming a solid solution. Depending on drug solubility in the carrier, a drug load varying from only a few percent up to 50%] Secondly, chitosan is ...
Size and stability: Liquid formulation can be bulky, difficult to transport and store.1 During storage under the stated conditions, it’s necessary that oral solutions are not subject to precipitation, fast sedimentation, caking or formation of lump.2 They have poor stability compare to solid dosage form formulation due to hydrolysis.1 Therefore, it’s important to optimize the active ingredient stability in liquid formulation including those prepared from powder or granules.2
The percentage yield gained was 70% from the Fischer Esterification reaction, which evaluates to be a good production of yield produced as the reaction is known to be reversible where conditions such as the concentration of the reactants, pressure and temperature could affect the extent of the reaction from performing. These white crystalline crystals were tested for impurity by conducting a melting point analysis and taking spectrospic data such as the IR spectra, HNMR and CNMR to confirm the identification of the product. These spectrospic methods and melting point analysis confirmed the white crystalline crystals were benzocaine.
In order to separate the mixture of fluorene, o-toluic acid, and 1, 4-dibromobenzene, the previously learned techniques of extraction and crystallization are needed to perform the experiment. First, 10.0 mL of diethyl ether would be added to the mixture in a centrifuge tube (1) and shaken until the mixture completely dissolved (2). Diethyl ether is the best solvent for dissolving the mixture, because though it is a polar molecule, its ethyl groups make it a nonpolar solvent. The compounds, fluorene and 1, 4-dibromobenzene, are also nonpolar; therefore, it would be easier for it to be dissolved in this organic solvent.
The conical vial was placed in a small beaker and allowed to cool to room temperature. The mixture was Cooled thoroughly in an ice bath for 15-20 minutes and crystals collected by vacuum filtration on a Hirsch funnel. The vial was rinsed with about 5 mL of ice water and transferred into to the Hirsch funnel and again washed with two additional 5mL portions of ice water. Crystals were dried for 5-10 minutes by allowing air to be drawn through them while they remained on the Hirsch funnel. The product was transferred to a watch glass plate and allow the crystals to dry in air. Crude acetaminophen product was weighed and set aside a small sample for a melting point determination and a color comparison after the next step. Calculation of the percentage yield of crude acetaminophen (MW = 151.2). was done and recorded in the lab notebook.
Mixed melting point was used to confirm the identity of the product. The smaller the range, the more pure the substance. When the two substances are mixed; the melting point should be the same melting range as the as the melting range obtained after filtering. If the mixed melting point is lower one taken from the crystals, then the two substances are different.
Polymer-Polyethylene is partially crystalline as well as amorphous because it has crystalline and amorphous regions. Also it has linear chains so this is the simplest structure compared to a branched or network chain. This can be of an advantage to it over other types of materials as its good toughness and elongation makes it very significant in the engineering industry as it can be moulded or extruded into shape...
how they are classified. For a long time, I’ve been interested in crystals, so I’
Recrystallization is a technique used to purify solids that contains small amounts of impurities. It is used to isolate pure solids from a supersaturated solution leaving the impurities in the solvent (1). The solid containing the impurities is placed in a hot solvent and upon cooling the compound precipitates to its purified form while the impurities are left behind in the solvent (1). There are six steps when it comes to undergoing a recrystallization of a solid. The first step is choosing a suitable recrystallization solvent. This step is crucial when it comes to executing a successful recrystallization experiment. Solubility comes into play
Solids are more stable than liquids and gases. One type of solid is a Crystalline solid. The particles in a crystalline solid have a regular repeating pattern. The types of crystalline solids are metals, alloys, salts, valence crystals, molecular crystals, polymers, and plastics.