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Maliba Pharmacy College Literature Review
Veer Narmad South Gujarat University 49
Touitou E et al 39 describe a novel carrier for enhanced skin delivery, the ethosomal
system, which is composed of phospholipid, ethanol and water. Ethosomal systems
were much more efficient at delivering a fluorescent probe to the skin in terms of
quantity and depth, than either liposomes or hydroalcoholic solution. The ethosomal
system dramatically enhanced the skin permeation of minoxidil in vitro compared
with either ethanolic or hydroethanolic solution or phospholipid ethanolic micellar
solution of minoxidil. In addition, the transdermal delivery of testosterone from an
ethosomal patch was greater both in vitro and in vivo than from commercially
available patches. Skin permeation of ethosomal components, ethanol and
phospholipid, was demonstrated in diffusion-cell experiments. Ethosomal systems
were shown by electron microscopy to contain multilamellar vesicles. P-NMR studies
confirmed the bilayer configuration of the lipids. Calorimetry and fluorescence
measurements suggested that the vesicular bilayers are flexible, having a relatively
low Tm and fluorescence anisotropy compared with liposomes obtained in the
absence of ethanol. Dynamic light scattering measurements indicated that ethanol
imparted a negative charge to the vesicles. Experiments using fluorescent probes
and ultracentrifugation showed that the ethosomes had a high entrapment capacity
for molecules of various lyophilicities.
Bendas ER et al 40 compared the transdermal delivery of salbutamol sulfate (SS), a
hydrophilic drug used as a bronchodilator, from ethosomes and classic liposomes
containing different cholesterol and dicetylphosphate concentrations. The presence
of ethanol in the aqueous compartment of the ethosomal vesicles favored the
encapsulation of SS and enhanced its permeation via the skin of newborn mice
because of the synergistic effect of ethanol, vesicles and skin lipids. Ethosomal
systems are capable of delivering higher amounts of SS at a controlled release rate
through mice skin than classic liposomes.
Akiladevi D et al 42 demonstrated that ethosomes are noninvasive delivery carriers
that enable drugs to reach the deep skin layers and/or the systemic circulation.
Although ethosomal systems are conceptually sophisticated, they are characterized
by simplicity in their preparation, safety and efficacy, a combination that can highly
expand their application. Ethosomes are soft, malleable vesicles tailored for
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enhanced delivery of active agents. This article reviews various aspects of ethosomes
including their preparation, characterization, potential advantages and their
applications in drug delivery. Because of their unique structure, ethosomes are able
to encapsulate and deliver through the skin highly lipophilic molecules such as
cannabinoids, testosterone, and minoxidil, as well as cationic drugs such as
propranolol, trihexyphenidil, Cyclosporine A, insulin, salbutamol etc. Ethosomes
provides a number of important benefits including improving the drug’s efficacy,
enhancing patient compliance and comfort and reducing the total cost of treatment.
Enhanced delivery of bioactive molecules through the skin and cellular membranes
by means of an ethosomal carrier opens numerous challenges and opportunities for
the research and future development of novel improved therapies.
Touitou E et al 52 investigated the delivery of trihexyphenidyl HCl (THP) from
ethosomes versus classic liposomes. When compared with standard liposomes,
ethosomes had a higher entrapment capacity and a greater ability to deliver
entrapped drug to the deeper layers of skin. The flux of THP through nude mouse
skin from THP ethosomes was 87, 51 and 4.5 times higher than from liposomes,
phosphate buffer and hydroethanolic solution, respectively. The quantity of THP
remaining in the skin at the end of the 18-h experiment was statistically significantly
greater from the ethosomal system than from liposomes or a control hydroethanolic
solution. The results indicate that the ethosomal system may be a promising
candidate for transdermal delivery of THP.
Sathalia AH et al 95 investigated ethosomes as a possible vesicular carrier for
transdermal delivery of diclofenac potassium as an analgesic anti-inflammatory
agent. The study confirmed that ethosomes are very promising carrier for the
transdermal delivery of diclofenac potassium revealed from higher entrapment
efficiency, better stability profile and faster anti‐inflammatory efficiency. The
enhanced accumulation of diclofenac potassium via ethosomal carrier within the
skin might help to optimize targeting of this drug to the epidermal and dermal sites,
thus creating new opportunities for modern topical application of diclofenac
potassium in the inflammatory conditions.
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Garg AK et al 96 demonstrated that a significant amount of aceclofenac transported
across the skin when entrapped in ethosomes. The in vivo efficiency of aceclofenac
ethosomal gel was also found to be significantly higher than marketed aceclofenac
gel and the gel containing free drug which can be used for transdermal treatment of
the diseases like rheumatoid arthritis, where chronic use is needed.
Dave V et al 97 evaluate the transdermal potential of novel vesicular carrier,
ethosomes, bearing aceclofenac, Non-steroidal anti-inflammatory drugs (NSAIDs)
agents having limited transdermal permeation. Aceclofenac loaded ethosomal
carriers were prepared, optimized and characterized for vesicular shape and surface
morphology, scanning electronic microscopy (SEM), vesicular size, entrapment
efficiency, stability, in- vitro release study. The optimized ethosomal formulation
showed transdermal flux for ethanolic drug solution which is greater than that of
isopropyl alcohol solution. The result advocates the potential of ethosome
formulation to treat rheumatic disease where facilitated penetration of the drug into
muscle and synovial fluid is desirable
Kumar et al 98 reported ethosomes to be much more efficient in delivering drug to
the skin. Ethosomes are the non invasive drug delivery carriers that enable drugs to
reach the deep skin layers finally delivering to the systemic circulation. For optimal
skin delivery, drug should be efficiently entrapped within ethosomal vesicles.
Ethosomal drug delivery system is a new state of the art technique and easier to
prepare in addition to safety and efficacy. Ethosomes have become a area of
research interest, because of its enhanced skin permeation, improved drug delivery,
increased drug entrapment efficiency etc.
Dragicevic CN et al 99 demonstrated that liposome loaded with temoporfin (mTHPC)
containing ethanol led to a higher overall skin deposition of the highly hydrophobic
mTHPC compared to mTHPC–liposomes without ethanol. The highest amount of
mTHPC was delivered to the skin by liposomes containing 20% (w/v) ethanol, and
this amount would be sufficient for a topical PDT. However, regarding the SC the
penetration enhancing effect of liposomes containing 20% (w/v) ethanol was not
significantly higher than the effect of the ethanolic solution, but in the case of
deeper skin layers these liposomes provided a higher drug level. In addition, it was
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shown that there is no need to prepare liposomes with amounts of ethanol higher
than 20%, since already 20% (w/v) ethanol provided sufficiently high amounts of
mTHPC for the topical PDT in all skin layers. Therefore, liposomes containing 20%
(w/v) ethanol could be a promising tool for delivering highly hydrophobic drugs like
mTHPC to the skin.
Misra AN et al 100 prepared and characterized fluconazole encapsulated ethosomes
and assessed its comparative clinical efficacy in the treatment of candidiasis patients
against liposomal gel, marketed product and hydroethanolic solution of the drug. In
Vitro drug diffusion studies demonstrated that % drug diffused from ethosomes was
nearly twice than liposomes and three times higher than the hydroethanolic solution
across rat skin. The study showed that ethosomal formulation having lesser vesicle
size, higher entrapment efficiency and higher in vitro diffusion as compared with
against liposomal gel, marketed product and hydroethanolic solution.
Jun-Bo T et al 101 investigated the effect of ethosomal minoxidil on dermal delivery
and hair cycle of mice and showed that in the ethosomal minoxidil treated group,
hair follicles became bigger, and the hair papillae were completely surrounded by
the hair bulbs. Inside the bulbs there were lots of newly formed melanocytes located
in the deeper layer of the hypodermis.
Jain NK et al 102 investigated the mechanism for improved intercellular and
intracellular drug delivery from ethosomes. Transmission electron microscopy,
scanning electron microscopy, and fluorescence microscopy were employed to
determine the effect of ethosome on ultrastructure of skin. Cytotoxicity and cellular
uptake of ethosome were determined using T-lymphoid cell line (MT-2). The
optimized ethosomal formulation showed 25 times higher transdermal flux across
the rat skin as compared with that of lamivudine solution.
Girhepunje K et al 103 studied ethosomes as a possible vehicle for transdermal
delivery of ciclopirox olamine, an antifungal agent, from the study it was confirmed
that ethosomal formulation of ciclopirox olamine showed a higher entrapment
efficiency and better stability profile. The enhanced accumulation of ciclopirox
olamine via ethosomal carrier within the skin might help to optimize targeting of this
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drug to the epidermal and dermal sites. Thus it concluded that ethosome was a very
promising carrier for transdermal delivery and created a new opportunities for
topical application of ciclopirox olamine in the fungal infections.
Dubey V et al 104 studied ethosomes as a possible vehicle for transdermal delivery of
methotrexate (MTX), an anti-psoriatic, anti-neoplastic agent. The study confirmed
that ethosomes are a very promising carrier for the transdermal delivery of MTX as
revealed from an enhanced transdermal flux, lower lag time, higher entrapment
efficiency and better stability profile. The enhanced accumulation of MTX via
ethosomal carrier within the skin might help to optimize targeting of this drug to the
epidermal and dermal sites, thus creating new opportunities for well-controlled and
modern topical application of MTX in the treatment of psoriasis.
Touitou E et al 105 investigate the dermal and intracellular delivery of bacitracin, a
model polypeptide antibiotic, from ethosomes. Bacitracin and fluorescently labeled
bacitracin (FITC-Bac) ethosomes were characterized for shape, lamellarity, fluidity,
size distribution and entrapment capacity by scanning electron microscopy (SEM),
transmission electron microscopy (TEM), differential scanning calorimetry (DSC),
dynamic light scattering (DLS) and ultracentrifugation, respectively. Confocal laser
scanning microscopy (CLSM) experiments revealed that ethosomes facilitated the
copenetration of antibiotic and phospholipid into cultured 3T3 Swiss albino mice
fibroblasts. These results, confirmed by data obtained in fluorescent-activated cell
sorting (FACS) experiments, suggest that ethosomes penetrate cellular membrane
releasing the entrapped molecule within cells. Additional work was focused on skin
permeation behavior of FITC-Bac from ethosomal systems in in vitro and in vivo
experiments through human cadaver and rat skin, respectively. These studies
demonstrated that the antibiotic peptide was delivered into deep skin layers through
intercorneocyte lipid domain of stratum corneum.
Dubey V et al 106 investigated to evaluate the transdermal potential of novel
ethanolic liposomes (ethosomes) bearing Melatonin (MT), an anti-jet lag agent
associated with poor skin permeation and long lag time. MT loaded ethosomes were
prepared and characterized for vesicular shape and surface morphology, vesicular
size, entrapment efficiency, stability, in vitro skin permeation and in vivo skin
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tolerability. Transmission Electron Microscopy (TEM), Scanning Electron Microscopy
(SEM), and Dynamic Light Scattering (DLS) defined ethosomes as spherical,
unilamellar structures having low polydispersity and nanometric size range. The
current investigation revealed that MT loaded ethosomes provided an enhanced
transdermal flux, lower lag time, higher entrapment efficiency and low skin irritancy
potential, thus leading to the generic conclusion that this approach offers a suitable
approach for transdermal delivery of melatonin.
Saraf S et al 107 reported great advances which have been made in development of
novel drug delivery systems (NDDS) for plant actives and extracts. The variety of
novel herbal formulations like polymeric nanoparticles, nanocapsules, liposomes,
phytosomes, nanoemulsions, microsphere, transferosomes, and ethosomes has
been reported using bioactive and plant extracts. The novel formulations are
reported to have remarkable advantages over conventional formulations of plant
actives and extracts which include enhancement of solubility, bioavailability,
protection from toxicity, enhancement of stability, improved tissue macrophages
distribution, sustained delivery, and protection from physical and chemical
degradation.
Touitou E et al 108 investigate a new approach to treat deep skin and soft tissue
bacterial infections by dermal application of erythromycin in an ethosomal carrier.
The efficiency of ethosomal erythromycin applied to the skin-infected site was
compared with intraperitoneal erythromycin administration and with local
application of hydroethanolic erythromycin solution. The parameters evaluated were
the development of dermal wound, histological sections and bacterial count of the
infected tissue. The in vivo experiments demonstrated a very efficient healing of
Staphylococcus aureus-induced deep dermal infections when the mice were treated
with ethosomal erythromycin and concluded that therapy with ethosomal
erythromycin applied to the skin of Staphylococcus aureus-infected mice was as
effective as systemically administered erythromycin, suggesting a new possibility to
treat deep dermal infections by local application of antibiotic in ethosomal carrier.
Rao Y et al 109 developed a novel transdermal drug delivery system that facilitates
the skin permeation of finasteride encapsulated in novel lipid-based vesicular
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carriers (ethosomes). Finasteride ethosomes were constructed and the
morphological characteristics were studied by transmission electron microscopy. The
particle size, zeta potential and the entrapment capacity of ethosome were also
determined. In contrast to liposomes, ethosomes were of more condensed vesicular
structure and they were found to be oppositely charged. Ethosomes were found to
be more efficient delivery carriers with high encapsulation capacities. In vitro
percutaneous permeation experiments demonstrated that the permeation of
finasteride through human cadaver skin was significantly increased when ethosomes
were used. The finasteride transdermal fluxes from ethosomes containing
formulation were 7.4, 3.2 and 2.6 times higher than that of finasteride from aqueous
solution, conventional liposomes and hydroethanolic solution respectively.
Furthermore, ethosomes produced a significant finasteride accumulation in the skin,
especially in deeper layers. The study demonstrated that ethosomes are promising
vesicular carriers for enhancing percutaneous absorption of finasteride.
Fang Y et al 110 investigate the penetration behavior of 5-aminolevulinic acid (ALA) in
disordered skin. We employed a highly potent ethosomal carrier
(phosphatidylethanolamine; PE) to investigate the penetration behavior of ALA and
the recovery of skin in a hyperproliferative murine model. We found that the
application of ethosomes produced a significant increase in cumulative amounts of
5–26-fold in normal and hyperproliferative murine skin samples when compared to
an ALA aqueous solution; and the ALA aqueous solution appeared less precise in
terms of the penetration mode in hyperproliferative murine skin. After the
ethosomes had been applied, the protoporphyrin IX (PpIX) intensity increased about
3.64-fold compared with that of the ALA aqueous solution, and the penetration
depth reached 30–80 μm. The results demonstrated that the ethosomal carrier
significantly improved the delivery of ALA and the formation of PpIX in both normal
and hyperproliferative murine skin samples, and the expression level of tumor
necrosis factor (TNF)-a was reduced after the ALA–ethosomes were applied to treat
hyperproliferative murine skin.
Jain NK et al 111 aimed to formulate and characterize indinavir bearing ethanolic
liposomes (ethosomes), and to investigate their enhanced transdermal delivery
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potential. The prepared ethanolic liposomes were characterized to be spherical,
unilamellar structures having low polydispersity, nanometric size range, and
improved entrapment efficiency over other delivery formulations. Permeation
studies of indinavir across human cadaver skin resulted in enhanced transdermal flux
from ethanolic liposomes that was significantly greater than that with ethanolic drug
solution, conventional liposomes, or plain drug solution. Additionally, the ethanolic
liposomes showed the shortest lag time for indinavir, thus presenting a suitable
approach for transdermal delivery of this protease inhibitor.
Touitou E et al 112 investigated the efficiency of transcellular delivery into Swiss
albino mice 3T3 fibroblasts of molecules with various physico-chemical
characteristics from ethosomes, phospholipid vesicular carriers containing ethanol.
The probes chosen were: 4-(4-diethylamino) styryl-N-methylpyridinium iodide (D-
289), rhodamine red dihexadecanoylglycerophosphoethanolamine (RR) and
fluorescent phosphatidylcholine (PC). The penetration of these fluorescent probes
into fibroblasts and nude mice skin was examined by CLSM and FACS. CLSM
micrographs showed that ethosomes facilitated the penetration of all probes into
the cells, as evident from the high intensity fluorescence. In comparison, when
incorporated in hydroethanolic solution or classic liposomes, almost no fluorescence
was detected.
Rong H et al 113 prepared fluorescence ethosomes (ES-QDs) composed of hydrophilic
CdTe fluorescent clusters (quantum dots, QDs). The prepared ES-QDs with even
particle size were obtained by extruding the vesicles through polycarbonate
membrane filters and were characterized by TEM, SEM and photoluminescence
spectra. There in vitro experiments to penetrate into human skin scar were
performed by using the Franz diffusion cell. Results showed that the prepared ES-
QDs not only have the properties of ethosome to penetrate the skin scar tissues but
also have the fluorescence labeling properties of the quantum dots. The prepared
ES-QDs have potential clinical application in therapy of skin scar.
Tavares et al 114 have patented matrix type and reservoir/adhesive type transdermal
patch formulations of Felodipine in which was predominantly used d-limonine as
permeation enhancer.
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Wang WG et al 115 have formulated a transdermal patch comprising of Felodipine
and Metoprolol and carried out pharmacokinetic and bioavailability studies on
rabbit.
Trotta M et al 116 prepared oil/water microemulsions containing benzyl alcohol or
different ratios of benzyl alcohol and isopropyl myristate as oil phase and used them
as vehicles for the transdermal absorption of Felodipine. Skin permeation from the
microemulsions was compared with that from a drug suspension in an apparent
external phase of a microemulsion and with an aqueous drug suspension. The
highest flux was from the microemulsion with the highest solubility of Felodipine,
while the permeation rate decreased over time from the suspension in the apparent
external phase. The flux from the aqueous suspension was 10-50 times lower than
that from the microemulsions.
Jamieson G et al 117 have patented a transdermal gel of Ropinirole, present in
formulation either as base or as a salt. The gel comprised a hydro-alcoholic vehicle, a
co-solvent like propylene glycol, an antioxidant like sodium metabisulfite,
penetration enhancer like diethylene glycol monoether with myristyl alcohol, gelling
agent like hydroxy propyl cellulose and buffering agent like triethanolamine to keep
the pH between 7 and 8.5.
Basavaiah K et al 118 developed two separate methods, titrimetric and
spectrophotometric, using potassium bromated- bromide mixture for Felodipine
estimation in bulk drug and its formulation. The reported methods were found
applicable for formulations containing at least 5 mg of drug.
Atay O et al 119 have reported both HPLC and UV methods for estimation of
Felodipine in formulations using methanolic solution at λmax of 360 nm. The
reported UV method had LOD 2.5 and LOQ 5 µg/ml.
Narkhede MN et al 121 have developed a RP-HPLC method for estimation of
Felodipine in rat plasma. Chromatographic separation was achieved using mobile
phase (methanol and water) in the ratio 80:20 %v/v at a flow rate of 0.9 ml/min. The
wavelength of detection was 260 nm. The linearity of the method was established in
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the range 50 ng – 150 ng/ml. The limit of detection of Felodipine was 25 ng/ml and
limit of quantification was 50 ng/ml.
Ahnoff M 122 developed a method for plasma estimation of Felodipine by automated
capillary gas chromatography with electron capture detection. The day-to-day
reproducibility of the method was represented by a relative standard deviation (RSD)
of 5% for Felodipine concentration of 25 nmol/l. The minimum determinable
concentration (giving better than 15% RSD) was l-2 nmol/l (0.4-0.8 ng/ml).
Miglioranca LH et al 123 have developed a method for the determination and
quantitation of Felodipine, in human blood plasma by liquid chromatography
coupled with tandem mass spectrometry using nimodipine as internal standard.
Felodipine was extracted from 0.5mL human plasma by use of a liquid/liquid
procedure using diethyl ether / hexane (80/20, v/v) as eluent. The method included a
chromatographic run of 5 min using a C18 analytical column (100mm×4.6mmi.d.)
and the calibration curve was linear over the range from 0.02 to 10 ng/mL (r2 >
0.994). The between-run precision, determined as relative standard deviation of
replicate quality controls, was 5.7% (0.06 ng/mL), 7.1% (0.6 ng/mL) and 6.8% (7.5
ng/mL). The between-run accuracy was ± 0.0, 2.1 and 3.1% for the above-mentioned
concentrations, respectively.
Sreedevi V et al 124 have reported an LC-MS/MS method for estimation of Felodipine
in plasma and its stability in freeze thaw analyte employing Princeton SPHER C18
(150 x 4.6 mm i.d. of 5) as Stationary phase and as Mobile Phase, Acetonitrile : 2mM
ammonium acetate. The described LC MS method was linear over a concentration
range of 0.8-13.0ng/ml. Pantaprazole was used as internal standard. The limit of
detection (LOD) and the limit of quantification (LOQ) for Felodipine was 0.10 ng/ml,
0.50 ng/ml and for Pantaprazole 0.06, 0.21 ng/ml respectively. The stability of the
drug spiked human plasma samples during three freeze thaw cycles were stable in
plasma for about one month when stored at frozen state.
Patel DS et al 125 have reported an LC-MS/MS method using a Betabasic C8, 100 X
4.6, 5 μ for separation. The composition of mobile phase was Methanol:
(0.1%v/v)Ammonia in water [90: 10 % v/v]. The flow rate was maintained at 0.7
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ml/min. Clopidogrel was used as internal standards for Felodipine. The analysis was
performed by TSQ Quantum LC-MS/MS. Chromatograms were acquired using the
computer based LCquan 2.5.6 software. The standard curve employed for ranged
from 0.050 ng/ml to 10.000 ng/ml. The lower limit of quantification was 0.050 ng/ml
for Felodipine. The method was used for carrying out bioequivalence study on
Felodipine tablet formulation.
Shete Y et al 126 developed a simple, sensitive, rapid, accurate and precise
spectrophotometric method for estimation of Ropinirole hydrochloride in bulk and
tablet dosage forms. Ropinirole hydrochloride shows maximum absorbance at 250
nm with molar absorptivity of 8.703×103 l/mol.cm. Beer’s law was obeyed in the
concentration range of 5-35 µg/ml. Results of analysis were validated statistically
and by recovery studies.
Susheel JV et al 127 have reported two methods UV spectroscopy and HPTLC for the
determination of ropinirole in tablet dosage form are described. Detection wave
lengths for spectrophotometric and HPTLC methods were found to be 250 nm and
254 nm, respectively. For the spectrophotometric method the linearity was found to
be in the range of 5-30 mg/ml and for HPTLC method linearity was found to be
between 40 and 120 mg/ml.
Sreekanth N et al 128 developed a simple and accurate RP-HPLC method has for the
estimation of Ropinirole hydrochloride in bulk and pharmaceutical dosage forms
using C18 column 250 x 4.6 mm i.d, 5μm particle size in isocratic mode, with mobile
phase comprising of buffer (pH 6.0) and acetonitrile in the ratio of 50:50 v/v. The
flow rate was 0.5ml/min and detection was carried out by UV detector at 245nm.
The retention time for Ropinirole hydrochloride was found to be 4.867 min. The
proposed method has permitted the quantification of Ropinirole hydrochloride over
linearity in the range of 5-50μg/ml and its percentage recovery was found to be 99.3-
100.4%. The intra-day and inter-day precision were found 0.27% and 0.26%
respectively.
Azeem A et al 129 developed and validated accurate, sensitive, precise, rapid, and
isocratic reversed phase HPLC (RP-HPLC) method for analysis of Ropinirole in the
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bulk drug and in pharmaceutical preparations. The best separation was achieved on
a 250 ammonium acetate buffer (pH 7) 80:20 (v/v) as mobile phase, at a flow rate of
1 mL/min. UV detection was performed at 250 nm. The method was linear over the
concentration range 0.2–100 μg/mL (r = 0.9998), with limits of detection and
quantitation of 0.061 and 0.184 μg/mL respectively. The drug was subjected to
oxidation, hydrolysis, photolysis, and heat as stress conditions. Degradation products
resulting from the stress did not interfere with detection and assay of Ropinirole
hydrochloride and thus the method can be regarded as stability-indicating.
Bhatt J et al 130 have reported a liquid chromatography–mass spectrometry (LC–
MS/MS) method for determining Ropinirole in human plasma using Es-citalopram
oxalate as an internal standard. The method involved solid phase extraction from
plasma, reversed-phase simple isocratic chromatographic conditions and mass
spectrometric detection that enabled a detection limit at picogram levels. The
proposed method was validated with linear range of 20–1200 pg/ml. The extraction
recoveries for ropinirole and internal standard were 90.45 and 65.42%, respectively.
The R.S.D.% of intra-day and inter-day assay was lower than 15%.
Chambers E et al 131 have developed a UPLC-MS/MS method for Ropinirole
estimation in plasma in very low amounts (0.02 ng/ml). The assay was determined to
be linear over the required range of 0.02 to 20 ng/mL. All calibration curves had an r2
> 0.996. SPE recoveries for both Citalopram and Ropinirole were >90% for extracted
samples at the following concentration levels: 0.1, 1 and 10 ng/mL.