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Thermodynamic Correlation between Liquid-Liquid Phase Separation and Crystalline Solubility of Drug-Like Molecules. Pharmaceutics 2022; 14:pharmaceutics14122560. [PMID: 36559054 PMCID: PMC9782016 DOI: 10.3390/pharmaceutics14122560] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/21/2022] [Accepted: 11/21/2022] [Indexed: 11/25/2022] Open
Abstract
The purpose of the present study was to experimentally confirm the thermodynamic correlation between the intrinsic liquid−liquid phase separation (LLPS) concentration (S0LLPS) and crystalline solubility (S0c) of drug-like molecules. Based on the thermodynamic principles, the crystalline solubility LLPS concentration melting point (Tm) equation (CLME) was derived (log10S0C=log10S0LLPS−0.0095Tm−310 for 310 K). The S0LLPS values of 31 drugs were newly measured by simple bulk phase pH-shift or solvent-shift precipitation tests coupled with laser-assisted visual turbidity detection. To ensure the precipitant was not made crystalline at <10 s, the precipitation tests were also performed under the polarized light microscope. The calculated and observed log10S0C values showed a good correlation (root mean squared error: 0.40 log unit, absolute average error: 0.32 log unit).
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Cordery SF, Pensado A, Chiu WS, Shehab MZ, Bunge AL, Delgado-Charro MB, Guy RH. Topical bioavailability of diclofenac from locally-acting, dermatological formulations. Int J Pharm 2017; 529:55-64. [PMID: 28636892 PMCID: PMC5557682 DOI: 10.1016/j.ijpharm.2017.06.063] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 06/13/2017] [Accepted: 06/16/2017] [Indexed: 11/17/2022]
Abstract
Assessment of the bioavailability of topically applied drugs designed to act within or beneath the skin is a challenging objective. A number of different, but potentially complementary, techniques are under evaluation. The objective of this work was to evaluate in vitro skin penetration and stratum corneum tape-stripping in vivo as tools with which to measure topical diclofenac bioavailability from three approved and commercialized products (two gels and one solution). Drug uptake into, and its subsequent clearance from, the stratum corneum of human volunteers was used to estimate the input rate of diclofenac into the viable skin layers. This flux was compared to that measured across excised porcine skin in conventional diffusion cells. Both techniques clearly demonstrated (a) the superiority in terms of drug delivery from the solution, and (b) that the two gels performed similarly. There was qualitative and, importantly, quantitative agreement between the in vitro and in vivo measurements of drug flux into and beyond the viable skin. Evidence is therefore presented to support an in vivo - in vitro correlation between methods to assess topical drug bioavailability. The potential value of the stratum corneum tape-stripping technique to quantify drug delivery into (epi)dermal and subcutaneous tissue beneath the barrier is demonstrated.
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Affiliation(s)
- S F Cordery
- Department of Pharmacy & Pharmacology, University of Bath, Bath, UK
| | - A Pensado
- Department of Pharmacy & Pharmacology, University of Bath, Bath, UK
| | - W S Chiu
- Department of Pharmacy & Pharmacology, University of Bath, Bath, UK
| | - M Z Shehab
- Department of Pharmacy & Pharmacology, University of Bath, Bath, UK
| | - A L Bunge
- Chemical and Biological Engineering, Colorado School of Mines, Golden, CO, USA
| | | | - R H Guy
- Department of Pharmacy & Pharmacology, University of Bath, Bath, UK.
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Casiraghi A, Musazzi UM, Rocco P, Franzè S, Minghetti P. Topical Treatment of Infantile Haemangiomas: A Comparative Study on the Selection of a Semi-Solid Vehicle. Skin Pharmacol Physiol 2016; 29:210-9. [DOI: 10.1159/000447672] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 06/14/2016] [Indexed: 11/19/2022]
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Minghetti P, Cilurzo F, Casiraghi A, Montanari L, Fini A. Ex Vivo Study of Transdermal Permeation of Four Diclofenac Salts from Different Vehicles. J Pharm Sci 2007; 96:814-23. [PMID: 17286288 DOI: 10.1002/jps.20770] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The ex vivo permeation of diclofenac was studied using four different salts (sodium, potassium, diethylamine, and epolamine) dissolved in four different solvents (water, propylene glycol (PG), Transcutol, and oleic acid (OA)) as donor phases through a human skin membrane. The four salts show different solubility values and different behavior in the four solvents, which are also permeation enhancers and this fact further is connected to the permeation results. The same order of magnitude of fluxes through the membrane as those previously reported for acidic diclofenac released from buffer solutions of pH >7 were found, taking into account differences originated by different membranes and other parameters tested in the experiments. Saturation concentration for the four salts in different solvents, necessary to calculate permeation coefficients, was critically evaluated; a short discussion made it possible to explain that corrections in the solubility values must be considered, related to the complex behavior in solution of these salts. Statistical processing of the experimental data suggests that differences between the four salts in promoting absorption of the drug is unproven; while differences are evident between the solvents, water is the most effective enhancing vehicle. Aqueous formulations containing diclofenac salt with an organic base appear to be the best combination to promote permeation in topical applications.
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Affiliation(s)
- Paola Minghetti
- Istituto di Chimica Farmaceutica e Tossicologica, Università degli Studi di Milano, Milano, Italy
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Dali MM, Moench PA, Mathias NR, Stetsko PI, Heran CL, Smith RL. A rabbit model for sublingual drug delivery: Comparison with human pharmacokinetic studies of propranolol, verapamil and captopril. J Pharm Sci 2006; 95:37-44. [PMID: 16307454 DOI: 10.1002/jps.20312] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A rabbit model for investigating sublingual drug absorption was established yielding results consistent with clinical data reported in the literature. Using propranolol as a model compound the effect of formulation and dosing variables was explored as a means to characterize the limiting parameters of this model. In addition, verapamil and captopril were selected as reference compounds to compare this model to sublingual absorption in humans. Rabbits were dosed sublingually and systemic absorption was measured over time. Sublingual absorption of propranolol was dependent on dosing solution pH and volume. Intra-oral spray device did not affect the overall exposure compared to instillation using a syringe. Despite species and dosing regimen differences the relative bioavailabilities of propranolol and verapamil were very similar in rabbits and humans. In contrast, captopril absorption from the sublingual cavity of rabbits was low and did not agree with that observed in man. Here we report a sublingual rabbit model of drug delivery and its potential utility in preclinical development of intra-oral dosage forms.
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Affiliation(s)
- Manisha M Dali
- Bristol-Myers Squibb Pharmaceutical Research Institute, One Squibb Drive, New Brunswick, New Jersey 08903-191, USA.
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Anroop B, Ghosh B, Parcha V, Kumar A, Khanam J. Synthesis and comparative skin permeability of atenolol and propranolol esters. J Drug Deliv Sci Technol 2005. [DOI: 10.1016/s1773-2247(05)50025-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Conjeevaram R, Chaturvedula A, Betageri GV, Sunkara G, Banga AK. Iontophoretic in vivo transdermal delivery of beta-blockers in hairless rats and reduced skin irritation by liposomal formulation. Pharm Res 2004; 20:1496-501. [PMID: 14567646 DOI: 10.1023/a:1025726715063] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE To demonstrate the in vivo transdermal delivery and establish the comparative pharmacokinetics of five beta-blockers in hairless rat. METHODS Intravenous dosing was initially done via jugular cannula. For iontophoretic delivery, current (0.1 mA/cm2) was applied for 2 h through a drug reservoir patch containing the beta-blocker (10 mg/ml). Blood samples were collected and analyzed by stereoselective HPLC assays. Any irritation resulting from patch application was quantified by a chromameter. Multilamellar liposomal formulation was prepared by the thin-film hydration method and converted to unilamellar liposomes by extrusion. RESULTS With transdermal iontophoresis, therapeutically relevant amounts of propranolol (83.78 +/- 7.4 ng/ml) were delivered within an hour and lasted for up to 4 h. Cmax (185.1 +/- 56.8 ng/ml) was reached at hour 3. A significantly higher amount (p < 0.05) of sotalol HCl was delivered compared to other beta-blockers. There was no significant difference in the S/R ratio of AUC0-t for enantiomers after both intravenous and transdermal delivery. Skin irritation was significantly reduced (p < 0.05) when a liposomal formulation of the propranolol base was used rather than the base itself. CONCLUSIONS The comparative pharmacokinetics of intravenous and transdermal iontophoretic delivery of five beta-blockers in hairless rats was established. It was shown that there is no stereoselective permeation.
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Affiliation(s)
- Rajkumar Conjeevaram
- Department of Pharmaceutical Sciences, School of Pharmacy, Mercer University, Atlanta, Georgia 30341-4155, USA
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Oumada FZ, Ràfols C, Rosés M, Bosch E. Chromatographic determination of aqueous dissociation constants of some water-insoluble nonsteroidal antiinflammatory drugs. J Pharm Sci 2002; 91:991-9. [PMID: 11948538 DOI: 10.1002/jps.10096] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The purpose of this work is to propose a new, useful, and easy chromatographic method to determine accurately the aqueous dissociation constant of drugs sparingly soluble in water. The method uses the rigorous intersolvental pH scale, (w)(s)pH, i.e., the pH measurements are made in the mobile phase after mixing the aqueous buffer with methanol by a combined glass electrode previously standardised with common aqueous buffers. The measured pK allows the determination of the drug's pK(a) in the mobile phase, (w)(s)pK(a), which can be easily converted in the aqueous pK(a), (w)(w)pK(a), by means of previously established equations. A series of nonsteroidal carboxylic acids with antiinflammatory properties were selected to test the method because their aqueous pK(a) values, (w)(w)pK(a), had been previously evaluated from different approaches that gave consistent results. The comparison of the aqueous pK(a) values obtained by means of the proposed procedure with those of literature allows the accurate evaluation of this new methodology. The results obtained show very good precision and accuracy.
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Affiliation(s)
- Fadoua Z Oumada
- Departament de Química Analítica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Spain
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Saïd A, Makki S, Muret P, Humbert P, Millet J. Psoralens percutaneous permeation across the human whole skin and the epidermis in respect to their polarity (in vitro study). J Dermatol Sci 1997; 14:136-44. [PMID: 9039977 DOI: 10.1016/s0923-1811(96)00561-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
8-methoxypsoralen (8-MOP), 5-methoxypsoralen (5-MOP) and 4,5',8-trimethylpsoralen (TMP) are commonly used in PUVA therapy [psoralen (P) + ultraviolet light A (UVA) irradiation] to treat skin diseases such as psoriasis and vitiligo. In order to predict the choice of the suitable drug(s) for topical applications, with appropriate dosage, percutaneous permeation of the psoralens, in connection with their solubilities and partition coefficients in an octanol/water system, were investigated. The percutaneous penetration experiments were accomplished by the deposit of ethanolic psoralen solution onto human skin and epidermis fragments mounted on Franz cells. Six cells were employed for each psoralen solution and for the whole skin layer as well as for the epidermis. The diffused psoralens in the receptor solution (1.4%, of human serum albumin) were quantified by using high performance liquid chromatography. The solubilities and the partition coefficients (PC) were carried out in an octanol/water system, in triplicate by using spectrofluorimetry. The results demonstrated that cumulated permeated quantities (ng/cm2) over 24 h, across the whole skin and the epidermis were in the following order for the three psoralens: 8-MOP > 5-MOP > TMP. The lipophilicity, expressed via the log PC, was as follows: 1.93 +/- 0.01 (8-MOP), 2.00 +/- 0.01 (5-MOP) and 3.14 +/- 0.01 (TMP). It was inversely correlated with cumulated penetrated amounts over 24 h in both whole skin and epidermis. From these results, TMP could be predicted as the most convenient psoralen for topical applications, because of its weak penetrability. Considering the relationship between psoralens lipophilicity and permeation, only 5-MOP and 8-MOP could be used, topically or orally, especially in the case of generalised skin disorders.
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Affiliation(s)
- A Saïd
- Laboratoire de Pharmacie Galenique, Faculte de Medecine et de Pharmacie, Besancon, France
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Ràfols C, Rosés M, Bosch E. A comparison between different approaches to estimate the aqueous pKa values of several non-steroidal anti-inflammatory drugs. Anal Chim Acta 1997. [DOI: 10.1016/s0003-2670(96)00496-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Said A, Makki S, Muret P, Rouland JC, Toubin G, Millet J. Lipophilicity determination of psoralens used in therapy through solubility and partitioning: comparison of theoretical and experimental approaches. J Pharm Sci 1996; 85:387-92. [PMID: 8901074 DOI: 10.1021/js950367f] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The aim of this study was to determine and to compare experimental and theoretical solubilities (S) as well as partition coefficients (PC) in an octanol/water system of psoralen (P), 8-methoxypsoralen (8-MOP), 5-methoxypsoralen (5-MOP) and 4,5',8-trimethylpsoralen (TMP). For each psoralen, experimental results were performed in triplicate with a spectrofluorimetric technique. The measurements were achieved 10 times for each solution. The obtained order of the solubilities in pure octanol was 5-MOP approximately TMP > P > 8-MOP, while in water-saturated octanol it was expressed as follows: TMP approximately 5-MOP > P > 8-MOP. However, the following order was found for hydrophobicity: TMP > 5-MOP > 8-MOP > P. The solubility ratios (SR) in pure octanol and water were assessed (mean +/- SD): 3.13 +/- 0.01 (P), 2.60 +/- 0.01 (8-MOP), 3.75 +/- 0.01 (5-MOP), and 5.11 +/- 0.01 (TMP). In saturated phases, they were 3.27 +/- 0.01, 2.63 +/- 0.01, 3.85 +/- 0.01, and 5.32 +/- 0.01, respectively. The PCs were determined with low concentrations according to the Dearden and Bresnen32 method and they were 1.67 +/- 0.01, 1.93 +/- 0.01, 2.00 +/- 0.01, and 3.14 +/- 0.01, respectively. Solubility parameters (delta), in Hildebrand unit (H) or in (cal/cm3)1/2, were evaluated. They confirmed the polarity of psoralens, previously expressed through the PC, although the positional isomers (5-MOP and 8-MOP) revealed no difference. Hildebrand's approach to the solubility of regular solutions and Yalkowsky's concept of the solubility of nonelectrolytes and weak electrolytes in an octanol/water system permitted a comparison of the theoretical and experimental results. The perspective of this work is to use the physicochemical properties of the psoralens in practice for insuring convenient experimental assays and the prediction, in vitro, of the percutaneous absorption of these compounds.
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Affiliation(s)
- A Said
- Laboratoire de Pharmacie Galénique, Faculté de Médecine et Pharmacie, Besançon, France
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Liu CH, Ho HO, Hsieh MC, Sokoloski TD, Sheu MT. Studies on the in-vitro percutaneous penetration of indomethacin from gel systems in hairless mice. J Pharm Pharmacol 1995; 47:365-72. [PMID: 7494184 DOI: 10.1111/j.2042-7158.1995.tb05812.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The influence of co-solvents on the in-vitro percutaneous penetration of indomethacin from gel systems was studied using a simplex lattice experimental design. Gel formulations were prepared by gelling the vehicle mixture of water, either alcohol or isopropanol and either propylene glycol or PEG 400 with 1% w/w Carbomer 940. Hairless mouse skin was employed as the barrier in a Franz-type diffusion cell. The penetration rates at steady state for seven formulations were fitted to a polynomial equation based on this simple lattice method and a three-dimensional plot was constructed. The formulation having the maximal penetration rate was determined to be the vehicle with a solvent ratio of water: alcohol: propylene glycol equal to 15:33:52, and which possessed a solubility parameter of 15 and a drug solubility of around 10 mg mL-1. When the solubility parameter of the vehicle was > 15, the drug solubility increased. However, the penetration rate decreased with an increasing solubility parameter. For those vehicles with a solubility parameter < 15, both the drug solubility and the penetration rate decreased with a decrease in the solubility parameter. There was shown to be an approximately 20-fold increase in the relative enhancement factor when using both alcohol and isopropanol, but only a threefold increase for both propylene glycol and PEG 400, when compared with water.
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Affiliation(s)
- C H Liu
- School of Pharmacy, China Medical College, Taichung, Taiwan
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Maitani Y, Sato H, Nagai T. Effect of ethanol on the true diffusion coefficient of diclofenac and its sodium salt in silicone membrane. Int J Pharm 1995. [DOI: 10.1016/0378-5173(94)00192-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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