An examination of the aqueous solution solubility and batch crystallization kinetics of L-isoleucine at the 250 mL scale size under a poly-and isothermal process condition is presented. Solubility data determined are consistent with the existence of two L-isoleucine polymorphic forms, in which both forms have different solubility and they are enantiotropically related. These polymorphs (A and B) can be recovered at different cooling rates of cooling crystallization. Crystal characterization using optical microscopy, differential scanning calorimetry, X-ray powder diffraction, and Fourier transform IR microscopy confirm this polymorphic behavior. Polythermal crystallization kinetic studies revealed the crystallization temperature increases with cooling rate and solute concentration, which results in a decrease of the metastable zone width (MSZW) with a decreasing cooling/heating rate. The study also revealed that cooling rates affect the polymorph formation, where at cooling rates of 0.25-0.75 °C/min, form B is formed, while a more stable polymorph A can be recovered at a cooling rate of 0.10 °C/min. Isothermal studies showed that the range of nucleation rate is between 1.79 × 10 -5 and 7.53 × 10 -4 kg/(m 3 min), and the interfacial surface free energy at high and low supersaturation system is 1.74 and 0.576 mJ/m 2 , respectively. For a high supersaturation system, the critical cluster radius r* is between 5-17 Å, associated with between 3-121 molecules (N*), and for a low supersaturation system, r* is between 3 and 14 Å and N* is between 1 and 64. For a pH range of 5.1-6.3 and a temperature range between 10 and 80 °C, zwitterion species of L-isoleucine has remained as a dominating species in both solubility and crystallization studies. Thermodynamics properties generated from solubility data were also presented and discussed.

Bioplastics are kind of plastics produce from natural and renewable raw materials biomass sources such as sugarcane, corn starch, wood, waste paper, vegetable oils and fats, bacteria, algae, etc. Mostly, the commercial plastics in the marketplace are made from non-renewable petroleum based and this product can cause damaging to the ecosystem of the nature. Bioplastics are not harmful to nature environment because it can decompose back into carbon dioxide. Thus, the demand for applications of bioplastics are growing rapidly. The products made from bioplastics should be commercialize because they are renewable, biodegradable, compostable and environmentally friendly. The aims of this short review are to present about classifications of bioplastic, their advantages and disadvantages, processing, applications and challenges. Finally, the possible future developments of bioplastics are prospected.

Molecular modeling techniques using both the empirical atom−atom and ab initio quantum mechanical methods are used to simulate the morphology of L-isoleucine. The lattice energy calculated by using a selected potential function and an atomic charge set is in excellent agreement with experimental data where the percentage difference between the calculated and experimental lattice energies is less than 5%, hence confirming the suitability of the potential functions and methods chosen to calculate the partial atomic charges. Calculation of the atom−atom interactions also shows that the energy contribution to the lattice energy is dominated by the interatomic interactions between the carbonyl oxygens and the amino hydrogens, consistent with the large calculated electrostatic contribution to the lattice energy. The simulated crystal morphology shows an elongated hexagonal platelike morphology with dominant crystal facets of (001) and (001̅ ) together with minor ((01̅ 1) faces. Experimental studies of the closely related amino acid L-leucine as an additive to L-isoleucine reveal that the addition of L-leucine alters L-isoleucine morphology, forming a more isometric hexagonal shape crystal by reducing the growth along the b-axis of the L-isoleucine crystal. This observation is supported by modeling through assessment of binding of L-leucine on preferential sites of the crystal habit surfaces of L-isoleucine where additive binding is found to be most preferred on the (100), (1̅ 00), (110), and (011̅ ) facets. ■ INTRODUCTIONAmino acids, the fundamental building blocks for the selfassembly of polypeptides and proteins, are materials with significant importance in many applications in the pharmaceutical, food, and fine chemical industries. Predicting amino acids morphology and understanding the phenomenon of the selfassembly and molecular interaction of solvent and additive molecules in the host crystal interface 1−5 have been topical and attractive areas for fundamental research. As an example, in the case of glycine with additive, the crystallographic change of its morphology is due to the electrostatic repulsive interactions between anionic and α-glycine molecules at the enantiotropic faces and the interaction of molecular speciation of additives. 6The charged glycine species were found to selectively inhibit the nucleation and crystal growth of α-glycine, resulting in the formation of γ-glycine. 7 Manipulation of the growth of this polymorph by racemic hexafluorovaline additive on glycine has also been carried out 8 on the basis of the knowledge of exposed surface chemistry and intermolecular arrangement, i.e. the centrosymmetric form in α-glycine and the polar form in γ-glycine.L-Isoleucine represents an attractive model compound due to both its interesting crystal chemistry and its varied surface

Crystal morphology remains an important aspect in pharmaceutical industries and thus lengthy experimentally determined morphology becomes a routine. This leads to advancement of molecular modeling to assist in crystal morphology determination. Morphology of racemic ibuprofen can be grown in PEG 300 solvent and simulated via molecular modeling, the computational technique. The resulting morphology dictates its feasibility and prepares for further necessary control to produce desired morphology. Tuning up the morphology can be done by rationalizing out via molecular modeling the effect of the solvent and crystallization method. Solvent effect persists to influence crystal morphology mainly via interaction of hydrogen bond specific at different facets. However, the influence of solvent-surface interaction in enhancing or inhibiting crystal growth is still not completely resolved. To date, racemic ibuprofen grown in PEG 300 solvent is the first ever reported. The objective of this study is to compare experimental and predicted morphology of racemic ibuprofen using selected potential functions and charge set in vacuum condition. Racemic ibuprofen crystal morphology was grown in PEG 300 solvent via cooling at ambient temperature and predicted via attachment energy (AE) method using molecular modeling. It was found that the experimental morphology is tabular hexagonal while the predicted one is tabular octagonal. The facets were cleaved and its surface chemistry was explained. The predicted lattice energy with lowest percentage error of 0.02% is dominated by van der Waals force rather than electrostatic force.

Abstract. The importance of pharmaceutical co-crystals now has been recognized in order to improve the research and development in pharmaceutical industries. Low solubility of active pharmaceutical ingredient (API) has led to the growth of new pharmaceutical co-crystals formation as it enhances the physicochemical properties of the API. In this works, preparation of new co-crystal formation between ibuprofen (IBP) with selected amino acid compounds were performed by using dry grinding and liquid assisted grinding (LAG) techniques. Ibuprofen (IBP) was selected as the API meanwhile glycine (GLY), L-alanine (ALA) and L-proline (PRO) were selected as co-crystal former (CCF) agents. The products of IBP-co-former from grinding experiments for the formation of co-crystals were characterized and verified using X-Ray Powder Diffraction (XRPD), Differential Scanning Calorimetry (DSC) and Fourier Transform Infra-Red Spectroscopy (FTIR). The finding reveals that the IBP-PRO co-crystals have successfully formed. For IBP-PRO system, new crystalline peaks from XRPD were recorded at 2θ values of 4.374°, 5.436° and 10.944° from dry grinding technique and 4.41°, 5.436° and 10.962° for liquid assisted grinding (LAG) technique. A new melting point of 257.49 °C was discovered for IBP-ALA indicates the possibility of co-crystals formation. On the other hand, the analysis for IBP-GLY shows that no co-crystals formed in the system.