Review on Microspheres, and its Characterisation of Various Drugs

Swathi Krishna K V; Sainath H; Bhanu Prakash R; Rajeswari K; Pavithra G; Bhuvaneswari G; Jaya Prakash K

doi:ijebr.v1i2.377

Review on Microspheres, and its Characterisation of Various Drugs

¹ , Sainath H ¹ , Bhanu Prakash R ¹ , Rajeswari K ¹ , Pavithra G ¹ , Bhuvaneswari G ¹ , Jaya Prakash K ¹

1 Department of Pharmaceutics, Saastra College of Pharmaceutical Education & Research, Near Varigonda Jwalamuhi Temple, Muthukur Raod, Kakupalli, Nellore-524 311, Andhra Pradesh, India, +91 8309013961

Abstract

Targeted drug delivery is designed in such a way that it concentrate the drug in the targeted tissues and it tends to reduce the concentration of the medication in the other tissues. Hence, surrounding tissues are not affected by the drug. Microspheres are free flowing powders that contain proteins or synthetic polymers that are biodegradable and ideally possess particle size usually less than 200 µm. The best possible means to deliver the drug to the target site with specificity, if modified, and to maintain the desired concentration at the site of interest without untoward effects. These possess importance not only for prolonged release, but also for targeting the anticancer drugs. In future, particularly in diseased cell sorting, gene & genetic materials, diagnostics, safe, targeted and effective invivo delivery as well.

Keywords

Microspheres, Microspheres and its Types, Preparation Methods, Characterisation, Applications

Introduction

Microspheres are usually solid spherical particles with size ranging from 1-1,000 µm. They are free-flowing particles composed of synthetic polymers or proteins that are biodegradable in nature. They contain dispersed drug or drug that is dissolved in a matrix have the potential for specified drug release 1. They consist polymeric, waxy or other protective materials.

Materials Used in the Formulation of Microspheres:

Polymers are used in the preparation of microspheres, they are classified as follows:

Synthetic polymers are divided into two types:

1. Non-biodegradable polymers:

Example: Polymethyl methacrylate (PMMA), Epoxy polymers. Acrolein-glycidyl methacrylate.

2. Biodegradable polymers:

Example: poly alkylcyano acrylates, Lactides, glycolides and their copolymers, polyanhydrides.

Natural Polymers

They are obtained from different sources such as proteins, carbohydrates and chemically modified carbohydrates 2.

Examples: Proteins such as albumin, gelatin and collagen, carbohydrates such as agarose, carrageenan, chitosan, starch, as well as chemically modified carbohydrates such as poly dextran, poly starch are also used 3.

Types of Microspheres

Bio-Adhesive Microspheres

Adhesion will be characterised as adherence to the membrane by the use of the projecting the water soluble chemical compound properties. Bio-adhesive drug delivery system is delivery system uses the bio-adhesion property of a number of the polymers that become adhering on association and can be used for prolonged periods of time to direct drugs to a particular area of the body 4.

Floating Microspheres

Gastroretentive drug delivery ways are floating microspheres on the idea of non-effervescent design. The word used synonymously with floating microspheres is hollow microspheres, microballoons or floating microparticles. These are free flowing cells, varied in scale from 1 to 1000 μm 4.

Magnetic Microspheres

This delivery system is extremely a lot of necessary that initiates the localisation of the drug to the illness site. Carriers receive magnetic responses to a magnetic flux that are incorporated materials and are used for this type are chitosan, dextran etc.

Polymeric Microspheres

Biodegradable chemical compound microspheres Natural chemical compounds such as starch are used with the thought that they are biodegradable 5, biocompatible, and additionally Bioadhesive in nature.

Radioactive Microspheres

The microsphere subgroup that interacts radioactively and is often treated during a comparable manner as non-radioactive microspheres. However, the radioactive microsphere continuously includes one and generally a lot of radio-nuclides are involved in targetting to specified sites 6.

Methods of Preparation

Spray Drying Technique

This was used to epare polymer microsphere mixed charged with drug. This requires dispersing the raw substance into liquefied coating liquid 7, after which spraying the mixture into the air for surface solidification accompanied by fast solvent evaporation. This is speedy however can also additionally lose crystalinity because of fast drying.

Freeze Drying Technique

Freeze drying is used effectively in the manufacture of API protein microspheres. The process is freezing, sublimation, main drying and secondary drying. The freezing step takes into account the eutectic point of the components. Molecules by removing water, creating a glassy matrix, reducing intermolecular interaction by forming hydrogen bonds between molecules or dipole-dipole interactions 8.

Emulsion Solvent Evaporation Technique

In this, the drug is dissolved in a polymerpreviously mixed in chloroform and that solution is mixed with aqueous phase containing 0.2% sodium PVP as an emulsifier 9.

This mixture is stirred at 500 rpm and then the drug and the polymer are converted into fine droplets which solidified into rigid microspheres by evaporation of the solvent and kept at room temperature and then collected by filtration and is washed with water. E.g.: Aceclofenac microspheres.

Emulsion Solvent Diffusion Technique

The drug chemical compound mixture was dissolved during a mixture of ethyl alcohol and dichloromethane (1:1) then the mixture was added dropwise of sodium lauryl sulfate solution.

So, the shaped floating microspheres were washed and dried in a desiccator at area temperature. These microparticles were sieved and collected 10.

Double Emulsification Method

The Doppel-emulsion strategy needs admixture w / o / w (or) o / w / o process the double emulsion. The solution of the product is distributed in a continuous lipophilic organic phase. The continuous step that consists of a chemical compound solution that encapsulates medication observed in the scattered aqueous layer to make primary emulsion.

The microspheres stuffed with the drug prolonged the unharnessed of the medication 24 hours and were ascertained to be diffusion and erosion regulated 11.

Ionic Gelation Method

The alginate/chitosan particle system for releasing diclofenac sodium was made using this technique. 25% (w/v) diclofenac sodium was added to a 1.2% (w/v) aqueous solution of sodium alginate continued and then added slowly to a solution containing Ca2+/Al3+ and a solution of chitosan in acetic acid. Complete release was obtained at pH 6.47.2, but drug was not released at acidic pH 12.

Characteristics of Microspheres

Particle Size and Shape

The most widely used methods for visualize microparticles are light microscopy and scanning electron microscopy. Both can be used to determine the shape and external structure of microparticles 13.

SEM allows studies of the surfaces of the microspheres and after the particles have been sectioned.

Thermal Analysis

Thermal analysis techniques routinely analyse these changes using programmed temperature variations for heating and cooling, and defined sample pressures and atmospheres 13.

Table 1: Drugs with Different Polymers and its Evaluation Parameters

Authors	Drugs	Polymers	Excipients Used	Method of Preparation	Conclusion
K.Kannan et al. 14	Acetazolamide	Acrylate, methacrylate EudragitRL and Eudragit RS	Petroleum ether and light liquid paraffin (40:60)	Solvent evaporation technique	Sustained release of the formulation with Eudragit considering stirring speed and polymer ratio as major criteria. Combination of Eudragit RS & RL shows better release compared to Eudragit RS.
Shikha kesharvani et al. 15	Metformin hydrochloride	HPMC, Eudragit S100	Ethanol, Dichloromethane	Emulsification solvent evaporation method	The SEM results reveals that the particles are spherical in shape and are effective in controlled release mechanism following case 2 transport.
Sunil Datt Belwal et al. 16	Aceclofenac	Chitosan, lectins, polyacrylate, deacetylated gellan gum	Ethyl cellulose, Eudragit, PVA, ethanol, span 80, DCM	Emulsion cross-linking method, Solvent evaporation	Solvent evaporation technique has been successfully employed to produce Aceclofenac loaded ethyl cellulose and Eudragit microspheres with optimal drug encapsulation that sustained the drug release over a period of time
S. Sahu et al. 17	Captopril	Sodium alginate, Sodium CMC &HPMC	Sod. Alginate, Sod CMC, Calcium chloride, phosphate buffer	Ionic gelation technique.	Drug to polymer ratio, stirring speed were major highlights for obtaining spherical particles.
Mulugeta Fentie et al. 18	Furosemide	Ethylcellulose, HPMC, Tween 80.	Ethanol, dichloromethane, hydrochloric acid, sodium hydroxide.	Solvent evaporation method.	Floating microspheres of furosemide were successfully prepared that shows the sustained release of the drug by altering the ratio of Polymers, and drug.
Mahmoud M. A. Elsayed et al. 19	Tolmetin sodium	Methylene chloride, glacial acetic acid, light liquid paraffin.	Sodium alginate, Calcium carbonate, potassium dihydrogen orthophosphate.	Internal gelation technique	Coating the alginate microspheres with chitosan delayed the drug release by forming Alg-Ch complex. The microspheres were spherical in shape with large pores at D: P ratio1:1 while at 1:3 D:P ratio formed microspheres having a smooth surface and small pores. The change in chitosan concentration had a non-significant effect on drug.
L Pachuauet al. 20	Salbutamol sulphate and Theophylline	Ethylcellulose, acetone, Tween 80	water, phosphate buffer pH 7	Emulsion solvent evaporation technique.	Considering polymer-drug ratio alternately improves the efficiency and release rate of the microspheres. This helps in controlling asthmatic attacks and are proved successful.
Vikrant K. Nikam et al., 21	Ketoprofen	Polyvinyl acetate, hydroxypropyl cellulose	Ceresin Wax (gm) Bees Wax (gm)	Melt solidification technique.	The prepared microspheres were spherical and possess smooth surface with excellent micromeritic properties.
Krishna Sailaja A et al. 22	Ibuprofen	Ethylcellulose	Chloroform, 100ml of aqueous mucilage of 0.5% sodium cmc	Solvent evaporation technique	It can be concluded that F3 formulation with 9:7 to polymer ratio was considered as best formulation for the preparation of ibuprofen loaded ethyl cellulose microspheres.

S. Mohapatra et al. 23	Glipizide	Sodium alginate, HPMC K4 M, PEG4000 and Ethyl cellulose	Glipizide, Sodium Alginate, PEG 4000 Ethyl Cellulose HPMC K4M	Ionic gelation method	Improved bioavailability and reducing the frequency of administration thus minimizing the side effects along with patient compliance.

Manikandan Palanivelu. et al. 24	Ranitidine Hydrochloride	Carbopol 934, Chitosan, sodium alginate	Dichloromethane, Calcium carbonate, Tween 80, Glacial acetic acid, Conc Hydrochloric acid, Potassium bromide	Ionotropic Gelation Method, Solvent Evaporation Method.	Among all the formulation optimized (RF3) formulation shown the very good drug release and fulfil all the evaluation parameters effectively.

Satish Balakrishnabhise et al. 25	Rifampicin	Ethanol, Eudragit RLPO, Dichloromethane	RIF, Glyceryl monostearate, Eudragit RLPO, Ethanol AR and Dichloromethane (HPLC grade)	Emulsion solvent diffusion method	The stability of RIF is improved by using this technique and the drug release profile was up to 3 hrs. DSC studies proved that the drug was mostly in amorphous form.

R. N. Saha et al. 26	Diclofenac Sodium	Poly-lactic-co-glycolic acid, Ethylcellulose	Ethylcellulose, cyclohexane,	Phase separation-coacervation method	The mean particle size was found to be in between 49.94mm and 52.72 mm. Invivo pharmacodynamic studies proved the sustained release of the drug. Microsphere depot formulation is convenient technique for preparation of Parenteral formulations.

Sabdat O Ekama et al. 27	Maraviroc and tenofovir	Chitosan, MRS Agar,	Sodium tri polyphosphate, acetic acid,	Ionic gelation technique	The combination of both drugs shows efficient action on HIV-1BaL virus. The anti-retroviral drugs were predominantly released from the carrier polymer and didn't disrupt the growth of Lactic acid bacterial microflora.

A. Mishra et al. 28	Amlodipine Besylate	Ethylcellulose, Hydroxy propyl methyl cellulose, ethanol dichloromethane.	HPMC, Polysaccharides, ethyl cellulose, Dichloromethane.	Solvent evaporation method.	Availability of various dosage forms of AD also provides an option for prescribing depending on patients condition.

Pushpendra Kumar Khangar et al. 29	Sulfasalazine	Chitosan, light liquid paraffin, glutaraldehyde. heavy liquid paraffin, Span 85, isopropyl alcohol	Ethanol, methanol, 0.1N HCL, 0.1N NaOH, chloroform and 7.4 pH buffer, isopropyl alcohol.	Simple emulsification phase-separation technique, cross-linking method.	The microspheres showed favorable release profiles in simulated colonic fluid. Further evaluation of the carriers are needed to improve the treatment options for colonic diseases.

Naoki nagahara et al. 30	Amoxicillin	Carboxyvinyl, methylcellulose,	Hydrogenated castor oil, phosphate buffer.	Spray-chilling method.	The prepared ones are effective in clearing H. pylori than amoxicillin administered as amoxicillin suspension. Use of amoxicillin microspheres reduces toxicity

Pavani S, Mounika K et al. 31	Acyclovir	Chitosan and sodium alginate	Acyclovir, HCL, calcium chloride, glacial acetic acid.	Ionic gelation techniques	UV analysis of ACV and melting point were complied with standards. From the study it is evident that promising sustained release microspheres of ACV may be developed from ionic gelation techniques by using polymers chitosan and sodium alginate.

G. P. Agrawaleet al. 32	Albendazole	Chitosan, or b 2-amino-2-deoxy-d-glucose, liquid paraffin, toluene.	Chitosan hydrochloride, Glutaraldehyde	Emulsion method.	The effect of polymer concentration, stirring rate and concentration of cross-linking agent on the particle size of the microspheres which resulted in larger emulsion droplets and finally greater microsphere size.

Patil P.B. et al. 33	Atenolol and Propranolol	Chitosan, hydroxypropyl cellulose, poly (ethylene glycol), polyethylene glycol macromer, poloxamer, (PVP).	Sorbitan monooleate, PVP, PAA	Solvent diffusion method, Interpolymer complexation method.	It may be feasible to use PAA/PVP mucoadhesive microspheres as a gastro-retentive DDS for antihypertensive effect. The release rate of the Beta-blockers agents is reduced because of Slower dissolution rate of the polymer taken.

Drug Content

The combination need to be held apart to permit the debris to sediment and then wash. 1mL changed into moved into volumetric flask from the filtrate, and the extent changed into balanced with 0.1N NaOH [Table 1]. Drug changed into measured spectrophotometrically after the perfect dilution 34.

CONCLUSION

Microspheres are the drug carriers in novel drug delivery system and are effective in cancer therapy or in any other disease treatment like a pulmonary related, cardiac related, and nervous system.

ACKNOWLEDGEMENT

I would like to thank Dr G. H. Srinivaasa Rao Sir (Founder and Manager), Saastra College of Pharmaceutical Education & Research, Near Varigonda Jwalamuhi Temple, Muthukur Raod, Kakupalli, Nellore-524 311, Andhra Pradesh, India.

Funding Support

The authors declare that they have no funding support for this study.

Conflict of Interest

The authors declare that there is no conflict of interest for this study.

[1] Freitas, S, Merkle, H P & Gander, B . 2005. Microencapsulation by solvent extraction/evaporation: reviewing the state of the art of microsphere preparation process technology. Journal of Controlled Release 102(2):313–332.

[2] Sheikh, Aijaz A, Siddiqui, A R, Gawai, N M, Shaikh, S R & . 2013. Formulation and Pharmaceutical Evaluation of Mucoadhesive Microsphere of Clarithromycin and Omeprazole. Research Journal of Pharmacy and Technology 6(5).

[3] Das, M K, Ahmed, A B & Saha, D . 2019. Microsphere a drug delivery system: A review. Int J Curr Pharma Res 11(4):34–41.

[4] Kadam, N R & Suvarna, V . 2015. Microsphere: a brief review. Asian Journal of Biomedical and Pharmaceutical Sciences 5(47):13–19.

[5] Swapna, N & Jithan, A V . 2010. Préparation, Characterization in vivo Evaluation of Parenteral Sustained Release Microsphere Formulation of Zopiclone. Journal of Young Pharmacists 2(3):223–228.

[6] Jabar, A, Madni, A, Bashir, S, Tahir, N, Usman, F, Rahim, M A, Jan, N, Shah, H, Khan, A & Khan, S . 2021. Statistically optimized pentazocine loaded microsphere for the sustained delivery application: Formulation and characterization. PLOS ONE 16(4).

[7] Caine, M, Carugo, D, Zhang, X, Hill, M, Dreher, M R & Lewis, A L . 2017. Review of the Development of Methods for Characterization of Microspheres for Use in Embolotherapy: Translating Bench to Cathlab. Advanced Healthcare Materials 6(9):1601291.

[8] Sharma, N, Purwar, N & Gupta, P C . 2015. Microspheres as drug carriers for controlled drug delivery: A review. International Journal of pharmaceutical sciences and research 6(11):4579–4587.

[9] Mishra, R . 2021. Development and Optimization of Floating Microspheres in Amethopterin. Bioscience Biotechnology Research Communications 14(4):1538–1543.

[10] Soppimath, K S, Kulkarni, A R & Aminabhavi, T M . 2001. Development of Hollow Microspheres as Floating Controlled-Release Systems for Cardiovascular Drugs: Preparation and Release Characteristics. Drug Development and Industrial Pharmacy 27(6):507–515.

[11] Yang, L, Wang, S, Wang, R, Zheng, Q, Ma, Q, Huang, S, Chen, J & Zhang, Z . 2021. Floating chitosan-alginate microspheres loaded with chlorantraniliprole effectively control Chilo suppressalis (Walker) and Sesamia inferens (Walker) in rice fields. The Science of the Total Environment 783.

[12] Jain, S K, Awasthi, A M, Jain, N K & Agrawal, G P . 2005. Calcium silicate based microspheres of repaglinide for gastroretentive floating drug delivery: Preparation and in vitro characterization. Journal of controlled release 107(2):300–309.

[13] Abbas, A K & Alhamdany, A T . 2020. Floating Microspheres of Enalapril Maleate as a Developed Controlled Release Dosage Form: Investigation of the Effect of an Ionotropic Gelation Technique. Turkish Journal of Pharmaceutical Sciences 17(2):159–171.

[14] Tiwari, T, Jain, V, Jain, S K & Khangar, P K . 2021. Formation development and evaluation of microsphere of sulfasalazine for the treatment inflammatory bowel diseases. Journal of Drug Delivery and Therapeutics 11(5-S):124–127.

[15] Nagahara, N, Akiyama, Y, Nakao, M, Tada, M, Kitano, M & Ogawa, Y . 1998. Mucoadhesive Microspheres Containing Amoxicillin for Clearance of Helicobacter pylori. Antimicrobial Agents and Chemotherapy 42(10):2492–2494.

[16] Naresh, K, Pavani, S & Mounika, K . 2018. Formulation and Evaluation of Acyclovir Microspheres. Iraqi Journal of Pharmaceutical Sciences 27(1):1–7.

[17] Rai, G, Jain, S K, Agrawal, S, Bhadra, S, Pancholi, S S & Agrawal, G P . 2005. Chitosan hydrochloride based microspheres of albendazole for colonic drug delivery. Die Pharmazie 60(2):131–134.

[18] Patil, P B, Gawali, V U, Patil, H N, Hardikar, S R & Bhosale, A V . 2009. Preparation and evaluation of mucoadhesive microspheres of atenolol and propranolol. International Journal of Pharm Tech Research 1(3):639–643.

[19] Kannan, K, Karar, P K & Manavalan, R . 2009. Formulation and evaluation of sustained release microspheres of acetazolamide by solvent evaporation technique. Journal of Pharmaceutical Sciences and Research 1(1):36–39.

[20] Kesharvani, S, Jaiswal, P K, Mukerjee, A & Singh, A K . 2019. Formulation and Evaluation of Metformin Hydrochloride Loaded Floating Microspheres. International Journal of Pharmacy and Pharmaceutical Sciences 12(2):74–82.

[21] Belwal, Sunil Datt, Joshi, Deepika, Rautela, Archana & Kumar, Praveen . 2020. Formulation and evaluation of microsphere of aceclofenac. Journal of Advancement in Pharmacology 1(1):65–70.

[22] Sahu, S, Chourasia, A, Toppo, A & Asati, A . 2012. Formulation and evaluation of captropril microspheres by ionic gelation technique. Int. J. Pharm. Sci 3:1377–1379.

[23] Fentie, M, Belete, A & Gebre-Mariam, T . 2015. Formulation of sustained release floating microspheres of furosemide from ethylcellulose and hydroxypropyl methylcellulose polymer blends. Journal of Nanomedicine and Nanotechnology 6(1):1–5.

[24] Elsayed, M . 2021. Controlled release alginate-chitosan microspheres of tolmetin sodium prepared by internal gelation technique and characterized by response surface modeling. Brazilian Journal of Pharmaceutical Sciences 56.

[25] Pachuau, L, Sarkar, S & Mazumder, B . 2008. Formulation and evaluation of matrix microspheres for simultaneous delivery of salbutamol sulphate and theophylline. Tropical Journal of Pharmaceutical Research 7(2):995–1002.

[26] Nikam, V, Jain, S & Mohanta, G . 2020. Encapsulation of Ketoprofen loaded lipid microspheres: Preparation, characterization and release kinetics. Asian Journal of Pharmacy and Pharmacology 6(1):37–46.

[27] Sailaja, A Krishna & Anusha, K . 2015. Preparation and evaluation of ibuprofen loaded microspheres. International Journal of Basic and Applied Chemical Sciences 5(3):30–38.

[28] Mohapatra, S, Sen, S & Si, S C . 2014. Preparation and Evaluation Of Glipizide Microspheres Using Mucoadhesive Polymers. International Journal of Pharmaceutical Sciences and Research 5(1):189–192.

[29] Palanivelu, M . 2021. Formulation and Evaluation of Ranitidine Hydrochloride Loaded Floating Microspheres for the Treatment of Gastric Ulcer. International Journal of Current Science Research and Review 04(08):833–845.

[30] Bhise, S B . 2010. Formulation and In Vitro Evaluation of Rifampicin Loaded Porous Microspheres. Scientia Pharmaceutica 78(2):291–302.

[31] Sajeev, C, Archna, R, Gupta, V, Sobti, A & Saha, R . 2003. Formulation and Evaluation of Parenteral Sustained Release Microspheres of Diclofenac Sodium. Scientia Pharmaceutica 71(2):101–111.

[32] Ekama, S O, Ilomuanya, M O, Azubuike, C P, Bamidele, T A, Fowora, M A, Aina, O O & Igwilo, C I . 2021. Mucoadhesive Microspheres of Maraviroc and Tenofovir Designed for Pre-Exposure Prophylaxis of HIV-1: An in vitro Assessment of the Effect on Vaginal Lactic Acid Bacteria Microflora. HIV/AIDS 13:399.

[33] Mishra, A, Mazumder, R & Sharma, M . 2014. Formulation and evaluation of floating microsphere of amlodipine besylate by using ethyl cellulose and hpmc. Pharmacophore 5(4):602–609.

[34] Srikar, G . 2018. Floating microspheres: A prevailing trend in the development of gastroretentive drug delivery system. Asian Journal of Pharmaceutics (AJP) 12(04).