GI Absorption of two Crystal Forms of Sulfameter in Man

Khalil, Said A.; Moustafa, M. M.; Ebian, A. R.; Motawi, M M

doi:10.1002/jps.2600611015

Cited by 30 publications

(41 citation statements)

References 14 publications

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“…Thus, in view of the current emphasis on understanding molecular mechanism in terms of spatial arrangement of component atoms of the ligands in the vicinity of the receptors (3,4), it is imperative that information on molecular properties of the toxins and xenobiotics is invariably given while describing their biologic activity. The two forms of lantadene A might differ in their bioavailability similar to observations on bioavailability for drugs such as chloramphenicol, sulfonamides, and aspirin (13, 24,31,32). The molecular aspects of gastrointestinal biotransformation, if any, and of the uptake and transport of lantadene A are not yet known.…”

Section: Discussionmentioning

confidence: 68%

Molecular structure, polymorphism, and toxicity of lantadene a, the pentacyclic triterpenoid from the hepatotoxic plant Lantana camara

Sharma

Dawra

Pattabhi

1991

J. Biochem. Toxicol.

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Lantadene A (22 beta-angeloyloxy-3-oxo-olean-12-en-28-oic acid), a pentacyclic triterpenoid compound from lantana (Lantana camara) leaves has been obtained in two polymorphic forms I and II. Form I had white, fluffy, and rod-shaped uniform crystals. Form II particles were irregular, shining, and polyhedral. The two forms differed in melting behavior. The powder x-ray diffraction of form I showed sharp peaks whereas from II did not contain distinct peaks. From single-crystal three-dimensional x-ray structure determination, the molecular structure of form I has been established. A/B and B/C rings of the molecule are trans fused while D/E rings are cis fused. The packing of the molecule is stabilized by hydrogen bonding. Form I of lantadene A was non-toxic to guinea pigs on oral administration. Form II induced ictericity and toxicity associated with decrease in feed intake and fecal output, hepatomegaly, increase in plasma bilirubin, and acid phosphatase activity.

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Section: Discussionmentioning

confidence: 68%

Molecular structure, polymorphism, and toxicity of lantadene a, the pentacyclic triterpenoid from the hepatotoxic plant Lantana camara

Sharma

Dawra

Pattabhi

1991

J. Biochem. Toxicol.

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show abstract

“…1,3,4) In addition, the relative thermodynamic stability of the polymorphs has also been of great interest. Polymorphs fall into one of two categories: a monotropic system or an enantiotropic system.…”

mentioning

confidence: 99%

A Novel Method for Estimation of Transition Temperature for Polymorphic Pairs in Pharmaceuticals Using Heat of Solution and Solubility Data.

Urakami

Shono

Higashi

et al. 2002

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…For primary structural characterization of individual components used for preparing MBFs the 13 C CP/MAS NMR spectra were measured (Figure 1). Signal assignment was performed on the basis of our experience and 13 C CPPI/MAS NMR experiments. As indicated by the relatively small linewidths of the signals of neat CPX (ca.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Molecular-Level Control of Ciclopirox Olamine Release from Poly(ethylene oxide)-Based Mucoadhesive Buccal Films: Exploration of Structure–Property Relationships with Solid-State NMR

et al. 2016

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Mucoadhesive buccal films (MBFs) provide an innovative way to facilitate the efficient site-specific delivery of active compounds while simultaneously separating the lesions from the environment of the oral cavity. The structural diversity of these complex multicomponent and mostly multiphase systems as well as an experimental strategy for their structural characterization at molecular scale with atomic resolution were demonstrated using MBFs of ciclopirox olamine (CPX) in a poly(ethylene oxide) (PEO) matrix as a case study. A detailed description of each component of the CPX/PEO films was followed by an analysis of the relationships between each component and the physicochemical properties of the MBFs. Two distinct MBFs were identified by solid-state NMR spectroscopy: (i) at low API (active pharmaceutical ingredient) loading, a nanoheterogeneous solid solution of CPX molecularly dispersed in an amorphous PEO matrix was created; and (ii) at high API loading, a pseudoco-crystalline system containing CPX-2-aminoethanol nanocrystals incorporated into the interlamellar space of a crystalline PEO matrix was revealed. These structural differences were found to be closely related to the mechanical and physicochemical properties of the prepared MBFs. At low API loading, the polymer chains of PEO provided sufficient quantities of binding sites to stabilize the CPX that was molecularly dispersed in the highly amorphous semiflexible polymer matrix. Consequently, the resulting MBFs were soft, with low tensile strength, plasticity, and swelling index, supporting rapid drug release. At high CPX content, however, the active compounds and the polymer chains simultaneously cocrystallized, leaving the CPX to form nanocrystals grown directly inside the spherulites of PEO. Interfacial polymer-drug interactions were thus responsible not only for the considerably enhanced plasticity of the system but also for the exclusive crystallization of CPX in the thermodynamically most stable polymorphic form, Form I, which exhibited reduced dissolution kinetics. The bioavailability of CPX olamine formulated as PEO-based MBFs can thus be effectively controlled by inducing the complete dispersion and/or microsegregation and nanocrystallization of CPX olamine in the polymer matrix. Solid-state NMR spectroscopy is an efficient tool for exploring structure-property relationships in these complex pharmaceutical solids.

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GI Absorption of two Crystal Forms of Sulfameter in Man

Cited by 30 publications

References 14 publications

Molecular structure, polymorphism, and toxicity of lantadene a, the pentacyclic triterpenoid from the hepatotoxic plant Lantana camara

Molecular structure, polymorphism, and toxicity of lantadene a, the pentacyclic triterpenoid from the hepatotoxic plant Lantana camara

A Novel Method for Estimation of Transition Temperature for Polymorphic Pairs in Pharmaceuticals Using Heat of Solution and Solubility Data.

Molecular-Level Control of Ciclopirox Olamine Release from Poly(ethylene oxide)-Based Mucoadhesive Buccal Films: Exploration of Structure–Property Relationships with Solid-State NMR

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