Intermolecular interactions between cucurbit[7]uril and pilocarpine.
The interactions between cucurbit[7]uril (CB7) macrocycles and pilocarpine (PIL) were investigated in aqueous solution by using (1)H NMR and circular dichroism (CD) spectroscopic techniques. The characterizations of the freeze-drying solid complex were conducted by electrospray ionization mass spectroscopy (ESI-MS), Fourier transform-infrared spectroscopy (FT-IR), thermogravimetry, and differential scanning calorimetry (DSC) techniques. The DSC and thermogravimetry confirmed the production of a thermally stable solid complex. The NMR, CD and ESI-MS measurements confirmed asymmetric induction during the complexation reaction, in which the γ-lactone ring of PIL (not the imidazole nucleus) has been fully encapsulated within the cavity of CB7. The stability of the drug has significantly enhanced as evidenced by the high-performance liquid chromatographic (HPLC) method. The results are discussed in the context of utilizing non-conventional supramolecular host-guest approaches to enhance the chemical stability in aqueous media of hydrophilic PIL drugs as model compounds. The non-classical stereospecific interactions between CB7 and PIL drugs are also highlighted.
Department of Chemistry, College of Science, United Arab Emirates University, P.O. Box 15551, Al-Ain, United Arab Emirates. Electronic address: n.saleh@uaeu.ac.ae.
Na'il
N
Saleh
College of Pharmacy, University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates.
Marieh B
MB
Al-Handawi
Department of Chemistry, College of Science, United Arab Emirates University, P.O. Box 15551, Al-Ain, United Arab Emirates.
Leena
L
Al-Kaabi
Department of Chemistry, College of Science, United Arab Emirates University, P.O. Box 15551, Al-Ain, United Arab Emirates.
Liaquat
L
Ali
Department of Chemistry, College of Science, United Arab Emirates University, P.O. Box 15551, Al-Ain, United Arab Emirates.
S
S
Salman Ashraf
Department of Chemistry, College of Science, United Arab Emirates University, P.O. Box 15551, Al-Ain, United Arab Emirates.
Thies
T
Thiemann
Department of Chemistry, College of Science, United Arab Emirates University, P.O. Box 15551, Al-Ain, United Arab Emirates.
Bassam
B
Al-Hindawi
Department of Chemistry, College of Science, United Arab Emirates University, P.O. Box 15551, Al-Ain, United Arab Emirates.
Mohammed
M
Meetani
D001952:Bridged-Ring Compounds / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D007093:Imidazoles / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010862:Pilocarpine / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils
D001952:Bridged-Ring Compounds; D007093:Imidazoles; D010862:Pilocarpine; C456276:cucurbit(7)uril; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils
Diasteroisomeric products; ESI-MS; HPLC; Pilocarpine; Polarimetry; Stability