scholarly journals In Situ-Forming Microparticles for Controlled Release of Rivastigmine: In Vitro Optimization and In Vivo Evaluation

2021 ◽  
Vol 14 (1) ◽  
pp. 66
Author(s):  
Mohamed Haider ◽  
Ibrahim Elsayed ◽  
Iman S. Ahmed ◽  
Ahmed R. Fares

In this work, sucrose acetate isobutyrate (SAIB) and polylactic co-glycolic acid (PLGA) were used alone or in combination as a matrix-former (MF) to prepare long-acting injectable rivastigmine (RV) in situ-forming microparticles (ISM). RV-ISM were prepared by the emulsification of an internal phase, containing the drug and the matrix former(s), into an external oily phase containing a stabilizer. The statistical design, Central Composite Design (CCD), was adopted as a quality by design (QbD) approach to optimize the formulation of RV-ISM systems. The fabricated RV-ISM systems was designed to minimize the initial burst drug release and maximize the sustainment of RV release from the ISM and ease of injection. The influence of critical formulation variables such as the matrix-former to drug (MF/D) ratio and SAIB to PLGA (S/P) ratio in the internal phase with respect to critical quality attributes (CQAs), such as the percentage drug release within the first day (Q1), the time required for 50% drug release (T50%) and the rate of injection, were studied using the CCD. The optimal RV-ISM system with the highest desirability value (0.74) was predicted to have an MF/D ratio of 11.7:1 (w/w) and an S/P ratio of 1.64:1 (w/w). The optimal RV-ISM system was assessed for its release profile, injectability, rheological properties, morphology, effect on cell viability, tolerance to γ-sterilization and in vivo performance in male albino rabbits. In vitro release studies revealed that the optimal RV-ISM system released 100% of its drug content throughout a release period of 30 days with only 15.5% drug release within the first day (Q1) and T50% of 13.09 days. Moreover, the optimal system showed a high injection rate of 1.012 mL/min, pseudoplastic flow, uniform spherical globules with homogenous particle size, minimal cytotoxicity and high tolerability to γ-sterilization. In vivo pharmacokinetic (PK) studies revealed that the rate of absorption of RV from the optimal RV-ISM system was controlled compared to a drug solution following either intramuscular (IM) or subcutaneous (SC) injection. Furthermore, the optimal RV-ISM was found to follow flip-flop PK with poor correlation between in vitro release and in vivo findings. These findings suggest that the optimal RV-ISM is a promising tool to achieve a sustained release therapy for RV; however, further investigation is still required to optimize the in vivo performance of RV-ISM.

2007 ◽  
Vol 25 (6) ◽  
pp. 1347-1354 ◽  
Author(s):  
Heiko Kranz ◽  
Erol Yilmaz ◽  
Gayle A. Brazeau ◽  
Roland Bodmeier

1970 ◽  
Vol 8 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Mohammad Nezab Uddin ◽  
Ishtiaq Ahmed ◽  
Monzurul Amin Roni ◽  
Muhammad Rashedul Islam ◽  
Mohammad Habibur Rahman ◽  
...  

The objective of this study was to design oral sustained release matrix tablets of Ranolazine usinghydroxypropyl methylcellulose (HPMC) as the retardant polymer and to study the effect of formulation factors suchas polymer proportion and polymer viscosity on the release of drug. In vitro release studies were performed usingUSP type II apparatus (paddle method) in 900 mL of 0.1N HCl at 100 rpm for 12 hours. The release kinetics wasanalyzed using the zero-order, first order, Higuchi and Korsmeyer-Peppas equations to explore and explain themechanism of drug release from the matrix tablets. In vitro release studies revealed that the release rate decreasedwith increase in polymer proportion and viscosity grade. Mathematical analysis of the release kinetics indicated thatthe nature of drug release from the matrix tablets was dependent on drug diffusion and polymer relaxation andtherefore followed non-Fickian or anomalous release. The developed controlled release matrix tablets of Ranolazineprepared with high viscosity HPMC extended release up to 12 hours.Key words: Ranolazine; Sustained release; Methocel E50 Premium LV; Methocel K100LV CR; Methocel K4M CR;Methocel K15M CR.DOI: 10.3329/dujps.v8i1.5333Dhaka Univ. J. Pharm. Sci. 8(1): 31-38, 2009 (June)


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Elham Khodaverdi ◽  
Fatemeh Kheirandish ◽  
Farnaz Sadat Mirzazadeh Tekie ◽  
Bibi Zahra Khashyarmanesh ◽  
Farzin Hadizadeh ◽  
...  

In situ forming delivery systems composed of block copolymers are attracting substantial attention due to their ease of use, biocompatibility, and biodegradability. In this study, the thermoresponsive triblock copolymer PLGA-PEG-PLGA was studied as a dexamethasone delivery system. Dexamethasone, a synthetic glucocorticoid, is used clinically to improve inflammation, pain, and the hyperemesis of chemotherapy, and it is applied experimentally as a differentiation factor in tissue engineering. PLGA-PEG-PLGA was synthesised under microwave irradiation for 5 min. The obtained copolymer was characterised to determine its structure and phase transition temperature. An in vitro release study was conducted for various copolymer structures and drug concentrations. The yield of the reaction and HNMR analysis confirmed the appropriateness of the microwave-assisted method for PLGA-PEG-PLGA synthesis. Phase transition temperature was affected by the drug molecule as well as by the copolymer concentration and structure. An in vitro release study demonstrated that release occurs mainly by diffusion and does not depend on the copolymer structure or dexamethasone concentration.


Author(s):  
Chandra Sekhar Kolli ◽  
Ramesh Gannu ◽  
Vamshi Vishnu Yamsani ◽  
Kishan V ◽  
Madhsudan Rao Yamsani

The aim of this investigation was to develop and evaluate mucoadhesive buccal patches of prochlorperazine (PCPZ). Permeation of PCPZ was calculated in vitro using porcine buccal membrane. Buccal formulations were developed by solvent-casting technique using hydroxy propylmethyl cellulose (HPMC) as mucoadhesive polymer. The patches were evaluated for in vitro release, moisture absorption and mechanical properties. The optimized formulation, based on in vitro release and moisture absorption studies, was subjected for bioadhesion studies using porcine buccal membrane. In vitro flux of PCPZ was calculated to be 2.14 ± 0.01 µg. h–1.cm–2 and buccal absorption was also demonstrated in vivo in human volunteers.             In vitro drug release and moisture absorbed was governed by HPMC content. Increasing concentration of HPMC delayed the drug release. All formulations followed Zero order release kinetics whereas the release pattern was non-Fickian. The mechanical properties, tensile strength (10.28 ± 2.27 kg mm–2 for formulation P3) and elongation at break reveal that the formulations were found to be strong but not brittle. The peak detachment force and work of adhesion for formulation P3 were 0.68 ± 0.15 N and 0.14 ± 0.08 mJ, respectively. The results indicate that suitable bioadhesive buccal patches of PCPZ with desired permeability and suitable mechanical properties could be prepared


2021 ◽  
Vol 18 ◽  
Author(s):  
Saeed Bazraee ◽  
Hamid Mobedi ◽  
Arezuo Mashak ◽  
Ahmad Jamshidi

Introduction: Typically, in situ forming implants utilize Poly (lactide-co-glycolide) (PLGA) as a carrier and N-methyl-2-pyrrolidone (NMP) as a solvent. However, it is essential to develop different carriers to release various drugs in a controlled and sustained manner with economic and safety considerations. Objective: The present study aims to evaluate the in-vitro release of Bupivacaine HCl from in situ forming systems as post-operative local anesthesia. Methods: We used Sucrose acetate isobutyrate (SAIB), PLGA 50:50, and a mixture of them as carriers to compare the release behavior. Besides, the effect of PLGA molecular weight (RG 502H, RG 503H, and RG 504H), solvent type, and solvent concentration on the drug release profile was evaluated. The formulations were characterized by investigating their in-vitro drug release, rheological properties, solubility, and DSC, in addition to their morphological properties. Furthermore, the Korsmeyer-Peppas and Weibull models were applied to the experimental data. The results revealed that a mixture of SAIB and PLGA compared to using them solely can extend the Bupivacaine HCl release from 3 days to two weeks. Results: The DSC results demonstrated the compatibility of the mixture by showing a single Tg. The formulation with NMP had a higher burst release and final release in comparison with other solvents by 30% and 96%, respectively. Increasing the solvent concentration from 12% to 32% raised the drug release significantly, which confirmed the larger porosity in the morphology results. From the Korsmeyer-Peppas model, the mechanism of drug release is predicted to be non-Fickian diffusion.


Fig. 12 Scanning electron micrograph of D.L-PLA nanoparticles loaded with CGP 57813. (Ref. 51.) scanning force microscopy (also called atomic force microscopy), enable the visualiza-tion of nanoparticles at atmospheric pressure without gold coating [12,64]. Neverthe-less, the resolution obtained with these new tools is still lower than that with SEM. For size determination, transmission electron microscopy is not as widely used as PCS and SEM, but it is still a powerful method for determining the morphology of particles. With this technique, Fessi et al. [42] estimated the wall thickness of PLA nanocapsules. Krause et al. [18] described the highly porous structure of PLA nano-spheres prepared by the emulsion-evaporation procedure. VIII. IN VITRO RELEASE STUDIES In vitro release studies should in principle be useful for quality control as well as for the prediction of in vivo kinetics. Unfortunately, due to the very small size of the par-ticles, the release rate observed in vivo can differ greatly from the release obtained in a buffer solution. However, in vitro release studies remain very useful for quality control as well as for evaluation of the influence of process parameters on the release rate of active compounds. In vitro drug release from microdispersed systems has been exten-sively reviewed by Washington [65]. Depending on the type of polyester, drug release from nanoparticles can take place through several processes, of which the following appear to be the most important: (1) The drug may diffuse out of the carrier through the solid matrix; to allow complete release from the carriers, (the concentration of drug in the release medium should re-main infinitely low, which condition is known as sink condition); (2) The solvent may penetrate the nanoparticles and dissolve the drug, which then diffuses out into the re-lease medium. Depending on the physico-chemical characteristics of the particles, wa-ter can enter the particles through narrow pores or by hydration. Once the drug is dis-solved, the drug diffuses out of the particles. Here again, since diffusion is driving the

1998 ◽  
pp. 204-216

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1231
Author(s):  
Sandy Van Hemelryck ◽  
Rani Wens ◽  
Hannelore van Poppel ◽  
Milou Luijks ◽  
Koosha Shahidi ◽  
...  

This study evaluated in vitro and in vivo drug release of bedaquiline from in situ forming gels (ISGs) containing 200 mg eq./g bedaquiline fumarate salt prepared with four different grades of poly(d,l-lactide) (PDLLA) or poly(d,l-lactide-co-glycolide) (PLGA) with a lactide/glycolide ratio of 50/50 or 75/25 and acid (A) or ester (E) end-capping in N-methyl-2-pyrrolidone at a polymer/solvent ratio of 20/80% (w/w). Mean in vitro drug release in 0.05 M phosphate buffer pH 7.4 with 1% (w/v) sodium lauryl sulphate was 37.3, 47.1, 53.3, and 62.3% within 28 days for ISGs containing PLGA5050A, PDLLA, PLGA7525A, and PLGA7525E, respectively. The data suggested that drug release was primarily controlled by precipitated drug redissolving, rather than polymer erosion. In vivo pharmacokinetic profiles after subcutaneous injections in rats were comparable for all ISGs (mean half-lives (t1/2) ranged from 1411 to 1695 h) and indicated a sustained drug release when compared to a solution of bedaquiline fumarate salt in polyethylene glycol 400/water 50/50% (v/v) (mean t1/2 of 895 h). In conclusion, PLGA or PDLLA-based ISGs have shown potential for parenteral sustained delivery of bedaquiline, suggesting further preclinical and clinical studies. From a formulation point of view, this case example highlights the importance of the interplay between drug solubility in biological media and dissolution of drug precipitates, which, in addition to the incorporation of diffusion controlling polymers, governs the release of the active drug.


1994 ◽  
Vol 17 (2) ◽  
pp. 291-295 ◽  
Author(s):  
Shigeru AOKI ◽  
Hidenobu ANDO ◽  
Masaaki ISHII ◽  
Katsumi IDA ◽  
Sumio WATANABE ◽  
...  

2018 ◽  
Vol 10 (4) ◽  
pp. 153 ◽  
Author(s):  
Fadia Yassir Al-bazzaz ◽  
Myasar Al-kotaji

Objective: This work aims to formulate and evaluate an ophthalmic in-situ gel of ciprofloxacin hydrochloride (HCl) using poloxamer 407 (P407) as a gelling agent and hydroxypropyl methylcellulose (HPMC) as a viscosity modifier. The objective of this work was to prolong the contact time as the in-situ gel will be converted into a gel upon contact with the cul-de-sac. Methods: Ciprofloxacin HCl ophthalmic in-situ gel was prepared by utilizing (P407) as a temperature-dependent polymer while hydroxypropyl methylcellulose was used as a viscosity modifier. The system was evaluated for physical appearance, pH, drug content, sterility, irritancy and stability. In addition, gelation temperature and a viscosity at different shear rates and different temperatures were studied. The compatibility of the polymer with ciprofloxacin was studied by using fourier transform infrared spectroscopy (FTIR). The in vitro release of the drug was also evaluated and supported by a preliminary in vivo test.Results: The results showed that the prepared formulas were clear, with acceptable pH and the drug contents were within the acceptable limits. FTIR results detected no incompatibility between poloxamer 407 and ciprofloxacin HCl. Notably, the viscosity of the system showed a pseudoplastic behaviour where a reduction in viscosity upon increasing the shear rate was observed. The in vitro release study confirmed the prolongation of the release of the optimized formula (F6) up to 8 h. Upon application of F6 into eyes of rabbits there was no irritancy. In addition, in vivo elimination study showed a prolonged contact for the in-situ gel in comparison with the rapid clearance of eye drop. Stability study indicated the stability of the optimized formula (F6). Conclusion: The prepared optimized formula (F6) represents a successful, safe, stable and prolonged release in-situ gel formula of ciprofloxacin.


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